Perovskite solar cells (PSCs) have been attracted much attention due to their high-energy conversion effi-ciency and low production cost. However, the issues of stability and toxicity are still remained. Our group focuses on the fundamental studies of PSCs devices, including development of a series of materials for compact layer, active layer, hole transfer layer, as well as back electrode of PSCs.
In this lecture, we will introduce current progress of several types of Pb-free perovskites solar cells and remaining issues, as well as present the recent results of our group in development of Pb-free perovskites and application for solar cells.
Several Pb-free perovskites have been designed and synthesized in our gourp. The electronic and optical properties of the lead-free halide double perovskites Cs2NaBX6 (B = Sb and Bi; X = Cl, Br and I) were investigated by first-principles calculation to ascertain the potential application of solar energy conversion. The designed double perovskites also were synthesized and carried out the characterization. Another work is preparation of composite active layer of bismuth triiodide (BiI3) and a layered perovskite (CH3NH3)3Bi2I9 (MBI) by a simple solution method. The nano/macrostructures of composite active layer were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). We found that the nanostructures and morphology of Pb-free perovskites affect significantly the performance of the solar cells fabricated.
1. H.Zhou, Y.Shi, K.Wang, Q. Dong, and T. Ma., J.Physical Chemistry C. 2015, 31, 285
2. Q. Dong, Y. Shi, and T. Ma. J. Phys. Chem. C, 2015, 119 (19), 1021
3. K.Wang, Q. Dong, and T. Ma.,,Adv. Mater. 2016, DOI: 10.1002/adma.201505241
4. T. Xu, T. Ma, Phys. Chem. Chem. Phys., 2016,18, 27026-27050
5. S.Zhao, L. Gao, S. Hayase, T. Ma, RSC Advances, 2016, 6, 31968-31975
In recent years, lead-based perovskites have become the most promising photovoltaic material showing excellent photovoltaic performances. However, the lead-based perovskite encounters instability and toxicity issues caused by the generation of Pb2+, which is highly not beneficial to environment. In this study, we firstly reported the synthesis and characterization of a novel lead-free mixed chalcogen-halogen perovskite material, MABiI2S (MBIS), and determined its physical and optical properties by various testing methods. The MBIS possesses a low bandgap of 1.52 eV and exhibits good absorptions across the visible light spectrum. It is also worth noting that the MBIS displayed absorption up to over 1000 nm.