Baomin Xu1 Chun Cheng1 Yanqing Tian1

1, Southern University of Science and Technology, Shenzhen, , China

Perovskite solar cells (PSCs) have been received great interest in recent years due to the rapid increase of their solar power conversion efficiency (PCE). However, in order to commercialize PSCs there are still many challenges need to be solved, including fabricating high efficiency and highly stable PSCs using simple, scalable, affordable and eco-friendly process technologies. In this talk, I will introduce several efforts our team have done towards this objective. First, by simply adding 4-tert-butylpyridine (tBP) into the PbI2 precursor solution to enhance its hydrophobicity, we can fabricate highly stable PSCs in ambient air with PCE > 12.5% using spin coating method. Then I will present our work on improving PSCs performance and stability using inorganic perovskite quantum dots (QDs). All-inorganic cesium lead halide perovskite (CsPbX3, X = Cl, Br, I) nanocrystals (NCs) have been prepared, which exhibit near-unity photoluminescence (PL) quantum yields, narrow emission peak widths and anion-tunable absorption/emission wavelengths. By introducing stable α-CsPbI3 QDs as an interface layer between the perovskite film and the hole transport material (HTM) layer to improve the energy band matching, the PCEs of devices have been increased from 15.17% to 18.56%, with substantial improvement on stability as well. Thirdly, we have developed a heat assisted spin-coating (HASP) process to fabricate PSCs with inverted structure and using PbAc2 as the precursor. This new process allows us to avoid using the toxic anti-solvents such as toluene and chlorobenzene. The PCEs can reach 19.12% on glass substrate and 14.87% on flexible PEN substrate. Over 80% of the initial PCEs can be remained for 20 days in air without encapsulation, and for 60 days under simple encapsulation. Finally, I will introduce our work on developing new hole transporting materials to replace Spiro-OMeTAD in order to fabricate high-efficiency and stable PSCs with much lower cost.