Recent progress of minimal voltage losses for high-performance perovskite photovoltaics

Perovskite solar cells (PSCs) have been rapidly crowded into the emerging photovoltaic technology, exhibiting continuously boosted power conversion efficiencies (PCEs) over 25%. Despite the high PCE, the voltage loss (Vloss) of PSCs still need to be further reduced to achieve higher open-circuit voltage (Voc) and thus approaching its Shockley–Queisser limit. Great effort on minimizing the Vloss has been made by mainly suppressing non-radiative recombination in perovskite and/or relevant interface, maximizing initial radiative efficiency, and modifying energy level alignment in PSCs. However, a timely overview of the lowest Vloss values achieved and the strategies of suppressing Vloss for the PSCs based on the most prevalent perovskite compositions is still lacking. In this review, the definition and determining factors of Vloss are elucidated, and the state-of-the-art low Vloss values of PSCs based on various types of prevailing perovskites with variable bandgaps are comprehensively discussed. The strategies for suppressing Vloss of PSCs are highlighted, aiming to boost the fundamental understanding of related Vloss mechanisms. Finally, an insightful perspective on further suppressing the Vloss in PSCs is provided, targeting on achieving new record PCEs in PSCs.