Improving the photovoltaic performance for PbS QD thin film solar cells through interface engineering.

Interfaces exist between functional layers inside thin film optoelectronic devices, and it is very important to minimize the energy loss when electrons move across the interfaces to improve the photovoltaic performance. For PbS quantum dots (QDs) solar cells with the classical n-i-p device architecture, it is particularly challenging to tune the electron transfer process due to limited material choices for each functional layer. Here, we introduce materials to tune the electron transfer across the three interfaces inside the PbS-QD solar cell: (1) the interface between the ZnO electron transport layer and the n-type iodide capped PbS QD layer (PbS-I QD layer), (2) the interface between the n-type PbS-I layer and the p-type 1,2-ethanedithiol (EDT) treated PbS QD layer (PbS-EDT QD layer), (3) the interface between the PbS-EDT layer and the Au electrode.

Spray deposited polycrystalline MAPbBr thick films for hole-transport-material free solar cells.

A spray deposition procedure for the fabrication of polycrystalline MAPbBr thick films (20-100 μm) is developed and highly efficient (>5.5% under AM1.5 sunlight) hole-transport-material free perovskite solar cells are successfully made with 40 μm thick MAPbBr films.