BiBr3 as an additive in CsPbBr3 for carbon-based all-inorganic perovskite solar cell

The stable CsPbBr3 perovskite solar cell (PSC) has recently attracted wide attention, but its low photoelectric conversion efficiency is still the main concern at present. The quality of the perovskite absorber layer and the energy level matching between perovskite and hole transport layer (HTM) are important factors affecting the efficiency and stability of the PSCs. In this work, CsPbBr3 film is prepared by multi-step solution spin coating method. In preparation process, a layer of BiBr3 was modified on PbBr2 film before the CsBr coating to form CsPbBr3. This method can not only improve the crystal quality of perovskite, but also adjust the energy level to improve the carrier extraction. As the result, the photoelectric conversion efficiency (PCE) of carbon-based CsPbBr3 PSCs has been effectively improved to 8.73%. This work demonstrates an effective approach to the preparation of high-quality perovskite films.