Efficient wide-bandgap perovskite solar cells enabled by doping a bromine-rich molecule

Wide-bandgap (wide-E ( g ), similar to 1.7 eV or higher) perovskite solar cells (PSCs) have attracted extensive attention due to the great potential of fabricating high-performance perovskite-based tandem solar cells via combining with low-bandgap absorbers, which is considered promising to exceed the Shockley-Queisser efficiency limit. However, inverted wide-E ( g ) PSCs with a minimized open-circuit voltage (V (oc)) loss, which are more suitable to prepare all-perovskite tandem devices, are still lacking study. Here, we report a strategy of adding 1,3,5-tris (bromomethyl) benzene (TBB) into wide-E ( g ) perovskite absorber to passivate the perovskite film, leading to an enhanced average V (oc). Incorporation of TBB prolongs carrier lifetimes in wide-E ( g ) perovskite due to reduction of defects in perovskites and makes a better energy level matching between perovskite absorber and electron transport layer. As a result, we achieve the power conversion efficiency of 17.12% for our inverted TBB-doped PSC with an enhanced V (oc) of 1.19 V, compared with that (16.14%) for the control one (1.14 V).

Automated summary

Adding TBB into wide-bandgap perovskite absorber can passivate the perovskite film, reduce defects, and improve energy level matching, leading to enhanced power conversion efficiency and open-circuit voltage in inverted perovskite solar cells.