The hole transport layer(HTL)-free carbon-based perovskite solar cells(C-PSCs)are promising for commercialization owing to their excellent operational stability and simple fabrication process.However,the power convers...The hole transport layer(HTL)-free carbon-based perovskite solar cells(C-PSCs)are promising for commercialization owing to their excellent operational stability and simple fabrication process.However,the power conversion efficiencies(PCE)of C-PSCs are inferior to the metal electrode-based devices due to their open-circuit voltage(V_(oc))loss.Herein,time-resolved confocal photoluminescence microscopy reveals that grain boundary defects at the perovskite/carbon interface are very likely to function as nonradiative recombination centers in HTL-free C-PSCs.A versatile additive Li_(2)CO_(3)is used to modify the conformal tin oxide electron transport layer for HTL-free C-PSCs.Li_(2)CO_(3)modification can result in enhanced charge extraction and optimized energy alignment at electron transport layer/perovskite interface,as well as suppressed defects at perovskite top surface due to Li_(2)CO_(3)-induced formation of PbI_(2)crystallites.Such dual interfacial passivation ultimately leads to significantly improved Voc up to 1.142 V,which is comparable to the metal electrode-based devices with HTL.Moreover,a record-high PCE of 33.2%is achieved for Li_(2)CO_(3)-modified C-PSCs under weak light illumination conditions,demonstrating excellent indoor photovoltaic performance.This work provides a practical approach to fabricate low-cost,highly efficient carbon-based perovskite solar cells.展开更多
基金supported by the National Natural Science Foundation of China(62104059,12104126,61935016,52173153)Nature Science Foundation of Hebei Province(F2021202044)the Science Research Project of Hebei Education Department(ZD2021031)。
文摘The hole transport layer(HTL)-free carbon-based perovskite solar cells(C-PSCs)are promising for commercialization owing to their excellent operational stability and simple fabrication process.However,the power conversion efficiencies(PCE)of C-PSCs are inferior to the metal electrode-based devices due to their open-circuit voltage(V_(oc))loss.Herein,time-resolved confocal photoluminescence microscopy reveals that grain boundary defects at the perovskite/carbon interface are very likely to function as nonradiative recombination centers in HTL-free C-PSCs.A versatile additive Li_(2)CO_(3)is used to modify the conformal tin oxide electron transport layer for HTL-free C-PSCs.Li_(2)CO_(3)modification can result in enhanced charge extraction and optimized energy alignment at electron transport layer/perovskite interface,as well as suppressed defects at perovskite top surface due to Li_(2)CO_(3)-induced formation of PbI_(2)crystallites.Such dual interfacial passivation ultimately leads to significantly improved Voc up to 1.142 V,which is comparable to the metal electrode-based devices with HTL.Moreover,a record-high PCE of 33.2%is achieved for Li_(2)CO_(3)-modified C-PSCs under weak light illumination conditions,demonstrating excellent indoor photovoltaic performance.This work provides a practical approach to fabricate low-cost,highly efficient carbon-based perovskite solar cells.
