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

Wide‐bandgap (wide‐ E g , ∼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).