Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: red plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (338 mg, 5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 911 μL (6.9 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: Single crystal X-Ray diffraction

Description: A Bruker Molly or Duo instrument with MoKα IμS microfocus source (λ=0.71073 Å) and MX Optics was used. All samples were collected at 293 K. Data was integrated and corrected for absorption with APEX3 software.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: red plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (338 mg, 5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 911 μL (6.9 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: red plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (338 mg, 5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 911 μL (6.9 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: red plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (338 mg, 5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 911 μL (6.9 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: brown plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (450 mg, 6.67 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 383 μL (3.3 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: Single crystal X-Ray diffraction

Description: A Bruker Molly or Duo instrument with MoKα IμS microfocus source (λ=0.71073 Å) and MX Optics was used. All samples were collected at 293 K. Data was integrated and corrected for absorption with APEX3 software.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: brown plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (450 mg, 6.67 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 383 μL (3.3 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: brown plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (450 mg, 6.67 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 383 μL (3.3 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: brown plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (450 mg, 6.67 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 383 μL (3.3 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 232 μL (2 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: Single crystal X-Ray diffraction

Description: A Bruker Molly or Duo instrument with MoKα IμS microfocus source (λ=0.71073 Å) and MX Optics was used. All samples were collected at 293 K. Data was integrated and corrected for absorption with APEX3 software.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 232 μL (2 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 232 μL (2 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 232 μL (2 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (540 mg, 8 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 150 μL (1.3 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: Single crystal X-Ray diffraction

Description: A Bruker Molly or Duo instrument with MoKα IμS microfocus source (λ=0.71073 Å) and MX Optics was used. All samples were collected at 293 K. Data was integrated and corrected for absorption with APEX3 software.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (540 mg, 8 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 150 μL (1.3 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (540 mg, 8 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 150 μL (1.3 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: brown plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (450 mg, 6.67 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 383 μL (3.3 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (540 mg, 8 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 150 μL (1.3 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 232 μL (2 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: red plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (338 mg, 5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 580 μL (4.39 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: Single crystal X-Ray diffraction

Description: A Bruker Molly or Duo instrument with MoKα IμS microfocus source (λ=0.71073 Å) and MX Optics was used. All samples were collected at 293 K. Data was integrated and corrected for absorption with APEX3 software.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 232 μL (2 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After three hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: red plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (338 mg, 5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 580 μL (4.39 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: red plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (338 mg, 5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 580 μL (4.39 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: red plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (338 mg, 5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 580 μL (4.39 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: brown plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (450 mg, 6.67 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 250 μL (1.89 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: Single crystal X-Ray diffraction

Description: A Bruker Molly or Duo instrument with MoKα IμS microfocus source (λ=0.71073 Å) and MX Optics was used. All samples were collected at 293 K. Data was integrated and corrected for absorption with APEX3 software.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: brown plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (450 mg, 6.67 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 250 μL (1.89 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: brown plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (450 mg, 6.67 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 250 μL (1.89 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: brown plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (450 mg, 6.67 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 250 μL (1.89 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 150 μL (1.17 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: Single crystal X-Ray diffraction

Description: A Bruker Molly or Duo instrument with MoKα IμS microfocus source (λ=0.71073 Å) and MX Optics was used. All samples were collected at 293 K. Data was integrated and corrected for absorption with APEX3 software.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask. The solution was heated and stirred constantly. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 232 μL (2 mmol) of pentylamine was added to 50% aqueous H3PO2 (2 mL) and solution reacted slowly. The solution was cooled on a hot plate and eventually cooled to room temperature. After three hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: red plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (338 mg, 5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 580 μL (4.39 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: red plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (338 mg, 5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 580 μL (4.39 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: brown plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (450 mg, 6.67 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 250 μL (1.89 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: brown plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (450 mg, 6.67 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 250 μL (1.89 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 150 μL (1.17 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 150 μL (1.17 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 150 μL (1.17 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 150 μL (1.17 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), methylamine hydrochloride (≥98%), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: black plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. Solid methylamine hydrochloride (507 mg, 7.5 mmol, DRY) was added to the hot yellow solution, and a black powder precipitated. This dissolved under stirring and resulted in a bright yellow solution. 150 μL (1.17 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature. After two hours, crystals were completely formed.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: orange plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. 1159 μL (10 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: orange plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. 1159 μL (10 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: orange plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. 1159 μL (10 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: orange plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. 1159 μL (10 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: orange plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. 1159 μL (10 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), pentylamine 99%, H3PO2 (50 wt. % in H2O)

Product: orange plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. 1159 μL (10 mmol) of pentylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R.

• Rayan C Duke University

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: orange plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. 1000 μL (7.52 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R. Band gap energy was calculated based on the absorption edge and exciton peak of the optical absorption spectra.

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: orange plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. 1000 μL (7.52 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature.

Method: Photoluminescence microscopy

Description: Data was collected with a Horiba LabRam Evolution high-resolution confocal Raman microscope spectrometer (600g/mm diffraction grating, with a diode continuous wave laser (473 nm, 25 mW) and a Synapse charge-coupled device camera. PL energy was calculated by the PL peak position of the optical emission spectra.

Starting materials: Lead(II) oxide (PbO, <10 μm, ReagentPlus®, ≥99.9% trace metals basis ), HI (57 wt. % in H2O), hexylamine 99%, H3PO2 (50 wt. % in H2O)

Product: orange plate-like crystals

Description: PbO powder (2232 mg, 10 mmol) was dissolved in 57% w/w aqueous HI solution (16 mL) in a 50 mL glass flask by heating to boiling under stirring. A bright yellow solution resulted. 1000 μL (7.52 mmol) of hexylamine in 50% aqueous H3PO2 (2 mL) was slowly added. The solution was slowly cooled to room temperature.

Comment: Note that the n=1 C6N1 compound is specifically mentioned as crystallizing in an orthorhombic spacegroup in the reference, with associated PXRD data shown in Figure S10. In contrast, the n>1 C6N1 compounds crystallize in a monoclinic spacegroup.

Method: UV-vis absorption (diffused reflectance)

Description: Optical diffuse-reflectance measurements were conducted at room temperature. A Shimadzu UV-2600 PC double-beam, double-monochromator spectrophotometer was operating from 200 to 2500 nm. BaS4 was used as a non-absorbing reflectance reference. Reflectance v. wavelength data was collected and used to estimate the band gap by converting reflectance to absorbance via the Kubelka-Munk equation: α/S = (1-R)^{2}/2R.

• Volker Blum Duke University