Bulk Restructure of Perovskite Films via Surface Passivation for High- Performance Solar Cells

摘要

Defects in perovskite films and the suboptimal interface contact largely limitthe performance and stability of inverted perovskite solar cells (PSCs). Asimple surface post-treatment with N-benzyloxycarbonyl-d-valine (NBDV) isdeveloped to overcome these problems. The device performance followingNBDV treatment is systemically investigated. It is showed that NBDV surfacepost-treatment results in the bulk restructure of the entire perovskite film andimproves the film-forming property of [6,6]-phenyl-C_(61)-butyric acid methylester. The grain sizes, crystallinity, trap states, cathode interfaces, as wellas the built-in field are also improved, which result in PSC performance andstability enhancement. A relatively higher power conversion efficiency (PCE)of 21.80% is reached, which is comparable to the PCE record based on singlecrystalMAPbI3. Meanwhile, the PCE of the NBDV devices can retain ≈77%and 84% of the initial value after storage for 768 h (32 days) in air and 8376 h(349 days) in N_2, respectively, while the control devices only maintain ≈53%and 38% of their initial PCE values under the same exposure conditions.This work provides means to promote bulk, surface, and interface regulationtoward high performance and stable inverted PSCs.