The reduction of bulk trap defects in bromine-rich wide-bandgap (WBG) perovskites is crucial to enhancing open-circuit voltage (Voc) and fill factor (FF) towards high-performance indoor photovoltaics (IPVs). Here, we report one-step processed composite-based WBG perovskite adducts by adding oleylammonium iodide solution in trichloromethane as dual additives to the WBG perovskite precursors. The incorporation of a trace amount of dual additives enables a high-quality and less defective WBG perovskite film with mitigated halide segregation, leading to the suppression of bulk trap-induced non-radiative recombination losses. The NiOx-based inverted champion cell under one-sun illumination generates a record power conversion efficiency (PCE) of 21.97%, an impressive FF of 83.4%, a Jsc of 21.56 mA cm−2, and a Voc of 1.25 V for 1.71-electon-volt WBG perovskites. Such devices also show high operational stability over 800 hours during T95 lifetime measurements. Our cells under U30 light with 1000 Lux (338.2 μW cm−2) can obtain a certified record PCE of 44.72% with a high Voc of 1.069 V and an FF of 82.3%. This is, to our knowledge, the best reported certified performance for perovskite-based IPVs.
