Proceedings of International Conference on Perovskite and Organic Photovoltaics and Optoelectronics (IPEROP19)
Publication date: 23rd October 2018
Organic-inorganic perovskite materials have established themselves as the outstanding candidate for photovoltaic application due to its long exciton diffusion length, low exciton binding energy and high charge mobility. Intensive researches conducted on perovskite solar cells pertaining to the several optimizations on interface, perovskite crystal nucleation and growth lead to an enhanced trap passivation and reduced hysteresis behavior. For interface engineering, many complicated organic compounds were employed to realize rapid charge transfer at the interface and suppressed hysteresis.
However, potential defects in the interconnection among organic molecules will limit the effectiveness of interfacial trap passivation. This article describes inorganic sulfur functionalization at the interface to anchor SnO2 and perovskite simultaneously. Inorganic sulfur atoms functionalization was realized through xanthate decomposition on SnO2 substrate, which is expected to anchor SnO2 and perovskite simultaneously. Inorganic sulfur atoms can coordinate with Pb2+ in MAPbI3 perovskite near the interface, leading to larger perovskite grains, facilitating electron transport and reducing hysteresis behavior. Electron trap density at shallow trap state decreased significantly after interfacial sulfur functionalization as revealed by thermally stimulate current (TSC).The efficiency of MAPbI3 perovskite solar cells was increased significantly with enhanced long-term stability upon interfacial sulfur functionalization compared to that of without sulfur functionalization, furthermore, the device was fabricated under more than 60% humidity in an ambient air condition whose device performance is comparable to that fabricated in inert atmosphere. Additionally, increased electrostatic interaction between sulfur and perovskite resulted in considerable retardation of solar cell degradation after 70d air-storage. This method paves a potential way using inorganic atoms interfacial functionalization for higher efficiency with enhanced stability.