Crystal system: unknown
| Exciton binding energy, eV |
|---|
Starting materials: PEAI salt, SnI2 salt, stoichiometric ratio 2:1
Product: spin-coated thin film
Description: Starting materials dissolved in 4:1 DMF:DMSO solvent mixture, stirred for 30 min at room temperature. Substrate: Quartz substrate with 120 nm gold layer with interdigitated fingers. Precursor solution (0.1-0.3 molar) pipetted onto substrate and spin-coated, 4000 rpm / 30 seconds, targeting film thicknesses 80-300 nm.
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 binding energy, meV |
|---|
Starting materials: PEAI, SnI2, HI, H3PO2
Product: Single crystals of 2D tin halide perovskites. Thin flakes were then exfoliated from the single crystals.
Description: Single crystals synthesized by slow cooling method. Growth solution prepared with 0.16mmol PEAI, 0.40mmol SnI2, 2mL HI, and 0.2mL H3PO3 in a sealed glass vial and placed in a muffle furnace and heated until completely dissolved. Solution cooled to room temperature at a rate of 2°C/hour. Crystals were then dried and stored in a nitrogen glove box.
Method: Arrhenius formula fitting
Description: Temperature dependent PL measurements were conducted by combining a Linkam THMS600 stage with the Witec system. Air was purged from stage chamber with dry nitrogen to remove water and oxygen. Cooling rate set to 20 degrees Celsius/min. 50x objective lens used for signal collecting. Exciton binding energies extracted from Arrhenius formula fitting from the integrated PL intensity.