Crystal system: unknown
| Band gap (fundamental), eV |
|---|
Starting materials: PbO, HI, H3PO2, 2-thiopheneethylamine
Product: spin-coated thin film
Description: First step: TEA2PbI4 single crystal flakes synthesized as follows: Slow-cooling in HI method: 2.232g (10 mmol) of PbO dissolved in glass vial containing 10 mL of HI and 1.7 mL of H3PO2. Brought to near-boiling temperature. 10 mmol of the organic amine mixed with 5 mL HI, cooled in an ice bath. Solutions were mixed and heated, then cooled to room temperature, upon which single crystal flakes form. Crystals were then washed thrice with diethyl ether and dried under a vacuum. Second step (thin film formation): Flakes were dissolved in 4:1 DMF:DMSO solvent mixture, stirred for 30 minutes. Substrate: quartz substrate with 120 nm gold layer of interdigitated fingers. Precursor solution (0.1-0.3 molar) pipetted onto substrate and then spun at 4000 rpm for 30 seconds, targeting film thickness of 80-300nm.
Method: Electroabsorption
Description: Films were spin-coated onto interdigitated Au electrode array - 45 micron distance between opposing fingers. Samples mounted in cryostat with Cu wires soldered to opposing electrode stripes. Xe lamp light spectrally filtered, focused on sample and subsequently on UV-enhanced Si photodiode detector. Sample transmission, substrate transmission, and sample electrotransmission were collected in independent scans.Absorbance and electroabsorbance were then calculated from the respective transmissions. The fundamental gap is determined by the crossover point of absorption curves measured under different electric fields in the fundamental band gap region.
Comment: Significantly more detail in paper.
Crystal system: unknown
| Exciton binding energy, eV |
|---|
Starting materials: PbO, HI, H3PO2, 2-thiopheneethylamine
Product: spin-coated thin film
Description: First step: TEA2PbI4 single crystal flakes synthesized as follows: Slow-cooling in HI method: 2.232g (10 mmol) of PbO dissolved in glass vial containing 10 mL of HI and 1.7 mL of H3PO2. Brought to near-boiling temperature. 10 mmol of the organic amine mixed with 5 mL HI, cooled in an ice bath. Solutions were mixed and heated, then cooled to room temperature, upon which single crystal flakes form. Crystals were then washed thrice with diethyl ether and dried under a vacuum. Second step (thin film formation): Flakes were dissolved in 4:1 DMF:DMSO solvent mixture, stirred for 30 minutes. Substrate: quartz substrate with 120 nm gold layer of interdigitated fingers. Precursor solution (0.1-0.3 molar) pipetted onto substrate and then spun at 4000 rpm for 30 seconds, targeting film thickness of 80-300nm.
Method: Electroabsorption
Description: Films were spin-coated onto interdigitated Au electrode array - 45 micron distance between opposing fingers. Samples mounted in cryostat with Cu wires soldered to opposing electrode stripes. Xe lamp light spectrally filtered, focused on sample and subsequently on UV-enhanced Si photodiode detector. Sample transmission, substrate transmission, and sample electrotransmission were collected in independent scans.Absorbance and electroabsorbance were then calculated from the respective transmissions. The exciton binding energy arises as the difference of the 1s exciton peak energy observed in conventional absorption and the fundamental gap as determined by the crossover point of absorption curves measured under different electric fields in the fundamental band gap region.
Comment: Significantly more detail in paper.
Crystal system: unknown
| Exciton energy, eV |
|---|
Starting materials: PbO, HI, H3PO2, 2-thiopheneethylamine
Product: spin-coated thin film
Description: First step: TEA2PbI4 single crystal flakes synthesized as follows: Slow-cooling in HI method: 2.232g (10 mmol) of PbO dissolved in glass vial containing 10 mL of HI and 1.7 mL of H3PO2. Brought to near-boiling temperature. 10 mmol of the organic amine mixed with 5 mL HI, cooled in an ice bath. Solutions were mixed and heated, then cooled to room temperature, upon which single crystal flakes form. Crystals were then washed thrice with diethyl ether and dried under a vacuum. Second step (thin film formation): Flakes were dissolved in 4:1 DMF:DMSO solvent mixture, stirred for 30 minutes. Substrate: quartz substrate with 120 nm gold layer of interdigitated fingers. Precursor solution (0.1-0.3 molar) pipetted onto substrate and then spun at 4000 rpm for 30 seconds, targeting film thickness of 80-300nm.
Method: Electroabsorption
Description: Films were spin-coated onto interdigitated Au electrode array - 45 micron distance between opposing fingers. Samples mounted in cryostat with Cu wires soldered to opposing electrode stripes. Xe lamp light spectrally filtered, focused on sample and subsequently on UV-enhanced Si photodiode detector. Sample transmission, substrate transmission, and sample electrotransmission were collected in independent scans. Absorbance and electroabsorbance were then calculated from the respective transmissions.
Comment: Significantly more detail in paper.
Starting materials: HI (1.1eq), 1.0 mol/L solution of 2-thiopheneethylamine; PbI2
Product: Thin film of n=1 2D perovskite, characterized in paper but no unambiguous statement of thickness
Description: Synthesis of thiophene cations: HI (aq, 1.1eq) added dropwise to ethanol solution with thiophenealkylamine (1.0 eq) at 0 deg C. Solution gradually reached room temperature and poured into excess diethyl ether, forming precipitates that were then washed with Et2O. Salts were recrystallized from EtOH-Et2O mixtures. Synthesis of 2D perovskite films: Substrate indicated in original reference is FTO-coated glass was etched using zinc powder and HCl, then cleaned with Hellmanex, water, acetone, and 2-propanol. Perovskite precursor solution: dissolved thiophene alkylammonium and PbI2 (molar ratio 2:1) in DMF and DMSO (0.78:0.22 v/v mixed solvent). Further deposition details of the n=1 film remain unclear in the original reference.
Method: Photoluminescence spectroscopy
Description: Excitation wavelength: 450 nm. Measurement used a Fluorolog3-22 spectrofluorometer.
Crystal system: unknown
| Photoluminescence peak position, abs. units |
|---|
Starting materials: HI (1.1eq), 1.0 mol/L solution of 2-thiopheneethylamine; PbI2
Product: Thin film of n=1 2D perovskite, characterized in paper but no unambiguous statement of thickness
Description: Synthesis of thiophene cations: HI (aq, 1.1eq) added dropwise to ethanol solution with thiophenealkylamine (1.0 eq) at 0 deg C. Solution gradually reached room temperature and poured into excess diethyl ether, forming precipitates that were then washed with Et2O. Salts were recrystallized from EtOH-Et2O mixtures. Synthesis of 2D perovskite films: Substrate indicated in original reference is FTO-coated glass was etched using zinc powder and HCl, then cleaned with Hellmanex, water, acetone, and 2-propanol. Perovskite precursor solution: dissolved thiophene alkylammonium and PbI2 (molar ratio 2:1) in DMF and DMSO (0.78:0.22 v/v mixed solvent). Further deposition details of the n=1 film remain unclear in the original reference.
Method: Photoluminescence spectroscopy
Description: Excitation wavelength: 450 nm. Measurement used a Fluorolog3-22 spectrofluorometer.
Starting materials: HI (1.1eq), 1.0 mol/L solution of 2-thiopheneethylamine; PbI2
Product: Thin film of n=1 2D perovskite, characterized in paper but no unambiguous statement of thickness
Description: Synthesis of thiophene cations: HI (aq, 1.1eq) added dropwise to ethanol solution with thiophenealkylamine (1.0 eq) at 0 deg C. Solution gradually reached room temperature and poured into excess diethyl ether, forming precipitates that were then washed with Et2O. Salts were recrystallized from EtOH-Et2O mixtures. Synthesis of 2D perovskite films: Substrate indicated in original reference is FTO-coated glass was etched using zinc powder and HCl, then cleaned with Hellmanex, water, acetone, and 2-propanol. Perovskite precursor solution: dissolved thiophene alkylammonium and PbI2 (molar ratio 2:1) in DMF and DMSO (0.78:0.22 v/v mixed solvent). Further deposition details of the n=1 film remain unclear in the original reference.
Method: Thin Film X-Ray Diffraction
Description: XRD measured with Bruker D8 Advance diffractometer and non-monochromated Cu radiation. Patterns obtained using grazing incident diffraction geometry from Bruker D8 Discover diffractometer and non-monochromated Cu radiation at incident angle 2 deg.