The Exploration of Carrier Behavior in the Inverted Mixed Perovskite Single-Crystal Solar Cells

Perovskite single crystal (PSC) possesses fewer bulk defects than the polycrystalline film counterpart, which has received extensive attention in a number of optoelectronic device applications. But the management of carrier behavior in an efficient solar cell based on PSC is not reported yet. Here, the carrier behavior within the device based on the ITO/NiO_x/(FAPbI₃)_0.85(MAPbBr₃)_0.15/TiO₂/Ag structure (FA = CH(NH₂)₂ ⁺, MA = CH₃NH₃ ⁺), in which the mixed PSC is successfully implemented into solar cells for the first time, is investigated. The PSC films with lateral dimension from 500 µm to 2 mm and thickness over tens of micrometers, are obtained through the polydimethylsiloxane-assisted solvent evaporation method. The highest power conversion efficiency derived from the present device approaches 12.18%. It is revealed that the surface roughness and thickness of PSC, the operation temperature and thickness of transport layers, and the interfaces of transport layers/PSC largely impact the carrier extraction and device performance of the perovskite single-crystal solar cell (PSCSC). This work indicates that the carrier behavior in the absorber layer and transport layer has large impact on the performance of PSCSCs, while the underlying design rule represents an important step to advance the PSCSCs and other optoelectronic devices.