Starting materials: PbI2, toluene, butyric acid, butylamine, butylammonium iodide
Product: Powder film on glass substrate
Description: PbI2, butyric acid, toluene, and butylamine were mixed in a capped flask. Separately, butylammonium iodide was dissolved in toluene with butylamine and butyric acid. The two solutions were combined and stirred until an insoluble yellow solid precipitated. The solid was removed by centrifuging at 6000 rpm for 3 minutes. The yellow solid was redispersed in toluene and centrifuged a second time, to produce the final products. The paintlike paste was then deposited on a glass substrate. A Pasteur pipette was used to spread the paste over the surface and was then allowed to dry.
Method: Diffuse reflectance spectra
Description: Diffuse reflectance spectra were measured in a Shimadzu UV 2450 instrument. A Ba2SO4 powder palette was the reference used. The reflectance was converted to absorbance.
Starting materials: PbI2, toluene, butyric acid, butylamine, butylammonium iodide, anhydrous acetonitrile
Product: Thin film on glass substrate
Description: PbI2, butyric acid, toluene, and butylamine were mixed in a capped flask. Separately, butylammonium iodide was dissolved in toluene with butylamine and butyric acid. The two solutions were combined and stirred until an insoluble yellow solid precipitated. The solid was removed by centrifuging at 6000 rpm for 3 minutes. The yellow solid was redispersed in toluene and centrifuged a second time, to produce the final products. The solid material was dissolved in acetonitrile to a desired concentration and then was spin-coated onto a glass substrate at 3000 rpm for 30 seconds.
Method: UV-vis absorption
Description: An Agilent Carry 60 UV-vis instrument was used in transmission mode to measure the absorbance. A blank glass substrate was used as the baseline.
Starting materials: lead oxide (10 mmol), hydriodic acid (10 mL), hypophosphorous acid (1.7 mL ), C4H9NH3I
Product: (BA)2PbI4
Description: Single crystals of (BA)2PbI4 were synthesized in a method called acid precipitation. Through constant stirring and heating, lead oxide (10 mmol) was dissolved in a solution that contained hydriodic acid (10 mL) and hypophosphorous acid (1.7 mL). After, C4H9NH3I was added to the mixture, causing the bright yellow solution to change to an orange color precipitate. Continuous heating of the mixture followed until the precipitate was fully dissolved, forming orange crystals at room temperature. The crystals were obtained via filtration and bathed in diethyl ether.
Method: UV-visible absorption
Description: Optical diffuse-reflectance spectra were collected at room temperature using a Shimadzu UV-3600 plus UV-VIS-NIR spectrophotometer. The reflectance spectra were converted to absorbance by using the Kubelka-Munk transformation; (α/S = (1 − R)^2/2R); α is the absorption coefficient, S is the scattering coefficient, and R is the reflectance.