Local temperature reduction induced crystallization of MASnI3 and achieving a direct wafer production

Despite the rapid advancement of perovskite solar cells, the fundamental drawback of toxicity in lead based materials has largely limited their large-scale development and application. Hence, we developed a local temperature reduction induced crystallization (LTRIC) method to directly obtain a lead-free perovskite wafer (CH3NH3SnI3), which is 110 mu m-thick, in an oil bath. The XRD diffraction peaks of the MASnI(3) wafer are indexed to ( 001) and its parallel crystal planes, demonstrating its high orientation. The UV-vis-NIR discloses that the absorption onset of the MASnI3 wafer is red-shifted to 1015 nm, corresponding to a narrow bandgap of 1.21 eV.