The superoxide anion radical scavenger as interface layer for efficient Cs2AgBiBr6 solar cells

Superoxide anion radicals (O 2 •- ) are easily produced during the operation of perovskite solar cells. Removing O 2 •- can effectively improve the stability and enhance the photovoltaic performance of perovskite solar cells. Here, we introduce a superoxide anion radical scavenger, 2,2,6,6-tetramethyl-4-[3-(trimethylammonio)propoxy]-1-piperidinyloxy chloride (TMAP-TEMPO) as an interface layer in Cs 2 AgBiBr 6 solar cells. TMAP-TEMPO can effectively eliminate O 2 •- and enhance the photostability of Cs 2 AgBiBr 6 films. Furthermore, the incorporation of TMAP-TEMPO not only reduces the defects in the Cs 2 AgBiBr 6 film but also promotes the hole transport. It also optimizes the energy level arrangement of the Cs 2 AgBiBr 6 solar cells. Finally, the power conversion efficiency (PCE) of the TMAP-TEMPO-modified Cs 2 AgBiBr 6 solar cells increased from 2.57% to 3.10%, achieving a higher open-circuit voltage ( V OC ) of 1.22 V, which represents one of the highest V OC reported for Cs 2 AgBiBr 6 solar cells. Additionally, the unencapsulated target solar cells retained 82% of their initial PCE after 40 days of storage at 20–30 °C and 55–65% relative humidity, or 85% after 300 h of storage at 60 °C in a nitrogen glovebox, respectively. This work offers a promising strategy for enhancing the photovoltaic performance of Cs 2 AgBiBr 6 solar cells.