Henk Bolink, University of Valencia
Fully Evaporated High Efficiency Perovskite Based Solar Cells
Written by Xiwen Gong
Perovskite thin film solar cells synthesized by solution process have achieved high power conversion efficiency (PCE) of over 22%. There are certain advantages of the solution process, such as the ease to engineer the material composition, fast film formation, and low cost. However, it is also limited by the fact that this process relies on a toxic solvent, such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), for example. The crystallization dynamic is also difficult to control during the solution process.
Henk Bolink from the University of Valencia introduced an alternative synthetic solution utilizing evaporation techniques. The perovskite evaporation takes place under vacuum condition, which is widely used in the industrial deposition process. Vacuum deposition also shows advantages over solution process in producing materials with high purity, in large area, and with arbitrary thickness.
Through the dual-source evaporation method, researchers can fabricate close-packed uniform perovskite films with low roughness. The solar cell made with p-i-n structure through fully evaporated deposition reached a PCE of around 15%. The highest efficiency of 20.3% was achieved with devices structure with n-i-p structure, with optimized doping level in the electron and hole transport layer.