羟基功能化分子工程消除二维相壁垒实现高效宽带隙及全钙钛矿叠层太阳能电池OA

All-perovskite tandem solar cells(TSCs)demonstrate exceptional potential to overcome the single-junction efficiency limit through enhanced photon harvesting across the solar spectrum and suppressed thermalization effects,achieving theoretical power conversion efficiencies surpassing 44%.Wide-bandgap perovskites solar cells(WBG PSCs)are crucial for tandem photovoltaics,and have witnessed exponential progress during the last decade.However,these devices suffer from severe open-circuit voltage(VOC)deficits,primarily due to interfacial recombination and carrier transport losses.A major contributor to these losses is the uncontrolled formation of insulating two-dimensional(2D)perovskite phases during surface passivation.Here,we introduce 4-hydroxyphenylethyl ammonium iodide(p-OHPEAI)as a multifunctional molecular additive to address this critical trade-off.Unlike conventional phenethyl ammonium iodide(PEAI),which forms the insulating 2D phase and the invert electric field by vertical molecular orientation that impedes charge extraction,the hydroxyl group(-OH)in p-OHPEAI enables parallel molecular adsorption on perovskite surfaces via synergistic interactions between amino(-NH3)and-OH groups.This configuration effectively eliminates the formation of insulating 2D perovskite phase,passivates undercoordinated halide and lead vacancies,reducing non-radiative recombination.Additionally,the polarity of p-OHPEAI generates a dipole moment at the perovskite/electron transport layer(ETL)interface,optimizing energy-level alignment and facilitating electron extraction.By incorporating p-OHPEAI into 1.77 eV WBG PSCs,we achieved a remarkable VOC of 1.344 V,corresponding to a minimal voltage deficit of 0.426 V,which is among the lowest reported VOC-deficit values for the inverted WBG PSCs with bandgaps ranging from 1.75 to 1.80 eV.The optimized device delivered a power conversion efficiency(PCE)of 19.24%,demonstrating superior performance compared to conventional PEAI-passivated cells.When integrated into all-perovskite TSCs,this strategy enabled a champion PCE of 28.50%(with a certified efficiency of 28.19%).Furthermore,the devices exhibited excellent operational stability,maintaining over 90%of their initial efficiency after 350 h of continuous illumination,highlighting the robustness of the hydroxyl-driven passivation approach.The introduction of hydroxyl groups in passivation molecules provides a versatile strategy to balance defect suppression and charge transport,bridging the gap between high voltage and efficient carrier extraction.