Crystal system: monoclinic
| a: | 11.80550003 Å |
| b: | 8.450900078 Å |
| c: | 9.026200295 Å |
| α: | 90° |
| β: | 107.072998° |
| γ: | 90° |
Starting materials: 1,6-diaminohexane (98%), hydriodic acid (HI, 57% w/w in water and stabilized with 1.5% hypophosphorous acid), lead iodide (PbI2, 99.999%)
Product: block-like crystals
Description: 1 mol 1,6-diaminohexane was mixed with 2 mol equivalents of HI and was stirred for 2 hours in an ice bath. The resulting salt was recovered by evaporation of the solvent and washing with diethyl ether. PbI2 (2 mol equivalents) was dissolved in 4 mL HI. Diammonium iodide salt (1 mol equivalent) was dissolved in 3 mL HI. The two solutions were mixed and stirred at 90 degrees C for 1 hour and half of the solvent was evaporated. The stirring was stopped and the temperature was gradually decreased (5 degrees C/hour) to −10 °C.
Method: Single crystal X-ray crystallography
Description: Data were collected using a Bruker APEXII diffractometer (MoKα radiation), equipped with a CCD detector.
Starting materials: 1,6-diaminohexane (98%), hydriodic acid (HI, 57% w/w in water and stabilized with 1.5% hypophosphorous acid), lead iodide (PbI2, 99.999%), TiO2
Product: yellow film
Description: 1 mol 1,6-diaminohexane (98%) was mixed with 2 mol equivalents of HI and was stirred for 2 hours in an ice bath. The resulting salt was recovered by evaporation of the solvent and washing with diethyl ether . PbI2 (2 mol equivalents) was dissolved in 4 mL HI. Diammonium iodide salt (1 mol equivalent) was dissolved in 3 mL HI. The two solutions were mixed and stirred at 90 degrees C for 1 hour and half of the solvent was evaporated. The stirring was stopped and the temperature was gradually decreased (5 degrees C/hour) to −10 °C. 1:3.5 ratio of TiO2 Dyesol paste and ethanol (99.5%) produced a ∼250 nm mesoporous film on a microscopic slide. The film was sintered and was used as a substrate. DMF solution of the perovskite crystal was spin-coated and the film was heated at 90 °C for 10 min.
Method: UV-vis absorption
Description: Spectra were recorded using UV-visible Cary 300 spectrophotometer.
Crystal system: unknown
| Band gap (fundamental), eV |
|---|
Starting materials: PbO, HI, H3PO2, hexamethylenediamine
Product: spin-coated thin film, high crystallinity
Description: First step: HDAPbI4 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 (0.05-0.1 molar) pipetted onto substrate and then spun at 4000 rpm for 30 seconds, targeting film thickness of 80-300nm. Film was solvent-annealed, then enclosed with 2mL dH2O.
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, hexamethylenediamine
Product: spin-coated thin film, high crystallinity
Description: First step: HDAPbI4 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 (0.05-0.1 molar) pipetted onto substrate and then spun at 4000 rpm for 30 seconds, targeting film thickness of 80-300nm. Film was solvent-annealed, then enclosed with 2mL dH2O.
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, hexamethylenediamine
Product: spin-coated thin film, high crystallinity
Description: First step: HDAPbI4 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 (0.05-0.1 molar) pipetted onto substrate and then spun at 4000 rpm for 30 seconds, targeting film thickness of 80-300nm. Film was solvent-annealed, then enclosed with 2mL dH2O.
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.