Performance Improvement of All-Inorganic, Hole-Transport-Layer-Free Perovskite Solar Cells Through Dipoles-Adjustion by Polyethyleneimine Incorporating

In the increasingly rapid development of perovskite solar cells (PSCs), all-inorganic PSCs, especially Br rich all-inorganic PSCs, not only inherit the advantages of an adjustable bandgap, and excellent light absorption, but also has superior stability. To find a simple-process and low-cost way to increase perovskite performance, we try to adjust the conduction band of CsPbIBr2 with the help of dipoles induced by PEI incorporating. Furthermore, we use carbon as the negative electrode to abandon the noble metal and hole transport layer (HTL). Finally, the solar cells with the structure of fluorine-doped tin oxide (FTO)/TiO2/CsPbIBr2/Carbon are prepared. The V-oc and FF of the carbon-based, HTL-free and all-inorganic PSCs with polyethyleneimine (PEI) incorporating have an obvious improvement, and the champion device can get an efficiency of 7.5% with peak V-oc of 1.2 V and maximum FF of 65%, which is far beyond the one without PEI incorporating. Our work hopes to give an effective method to produce a simple, cost-effective design for PSCs.

Automated summary

Researcher adjusted the conduction band with PEI doping, used carbon as the negative electrode, and successfully prepared all-inorganic perovskite solar cells with improved efficiency. This study provides an effective method for simple, cost-effective design of PSCs.