Method: UV-vis absorbance
Description: Optical diffuse-reflectance measurements were executed at 298 K with a Shimadzu UV-3101 PC double-beam, double monochromator spectrophotometer between 200 to 2500 nm. One Nicolet 6700 IR spectrometer with a diffuse-reflectance kit was used for 4000-400cm^{-1} region. The reflectance vs. wavelength data was used to convert the data to absorption data via the Kubelka-Munk equation: α/S = (1-R)^2/2R.
Starting materials: PbBr2 (synthesized), HBr (48% aqueous), CsBr, ethanol (EtOH)
Product: Orange powder
Description: PbBr2 (7.31 g, 20 mmol) was dissolved in 30 mL HBr solution, and CsBr (4.26 mg, 20 mmol) was dissolved in 10 ml of H2O. Both of these solutions were mixed at room temperature. The obtained orange powder (CsPbBr3) was filtered, washed with EtOH, and dried under a vacuum.
Method: UV-vis absorbance (diffuse reflectance)
Description: Optical diffuse-reflectance measurements were executed at 298 K with a Shimadzu UV-3101 PC double-beam, double monochromator spectrophotometer between 200 to 2500 nm. One Nicolet 6700 IR spectrometer with a diffuse-reflectance kit was used for 4000-400cm^{-1} region. The reflectance vs. wavelength data was used to convert the data to absorption data via the Kubelka-Munk equation: α/S = (1-R)^2/2R.
Starting materials: Cs2CO3 (99.9%, Aldrich), octadecene (ODE, 90%, Aldrich), oleic acid (OA, 90%, Aldrich), PbCl2 (99.999%, Aldrich), PbBr2 (99.999%, Aldrich), PbI2 (99%, Aldrich), oleylamine (OLA, Aldrich, 70%), hexane
Product: CsPbBr3 and CsPb13
Description: A solution 5 mL of ODE and 0.18 mmol of PbX2 was degassed under vacuum and were then added to a mixture of OLA and OA, which was annealed at 120 degrees celsius. This solution was kept at a temperature of 150 degrees celsius as 0.6 mL of the inorganic-organic Cs-oleate solution was obtained. The reaction was then placed in a ice-water bath to isolate and purificate CsPbI3 and CsPbBr3 nanowires.
Method: Absorption Spectra
Description: A Shimudzu UV-3010 PC UV-VIS-IR Scanning spectrophotometer equipped with a Shimadzu ISR-3100 was used to obtain the wavelength and absorbance of CsPbBr3.