Tin-based perovskite solar cells(PSCs)are the most promising alternatives to toxic lead-based ones.However,the loss in open-circuit voltage(V_(OC))remains an important issue.Improvement of V_(OC)has been achieved by u...Tin-based perovskite solar cells(PSCs)are the most promising alternatives to toxic lead-based ones.However,the loss in open-circuit voltage(V_(OC))remains an important issue.Improvement of V_(OC)has been achieved by using a fullerene derivative,indene-C_(60)bisadduct(ICBA),as the electron transporting layer(ETL).For further V_(OC)improvement,the V_(OC)improvement mechanisms must be clarified.Herein,we show,at a molecular level,V_(OC)improvement mechanisms by an ICBA ETL in tinbased PSCs.Electron spin resonance spectroscopy reveals that electron diffusion from perovskite to ETL occurs at perovskite/ETL interfaces,producing unfavorable upward band-bending of perovskite.Employing ICBA with a shallower LUMO level suppresses the upward band-bending as well as reduces the energy offset with the conduction band minimum of perovskite.Suppressing this unfavorable upward band-bending reduces interface recombination at perovskite/ETL interfaces and contributes to V_(OC)improvement.These insights support efficient optimization of the chargetransporting layer for additional improvement of V_(OC).展开更多
基金supported by Japan Science and Technology Agency,MIRAI(JPMJMI20C5,JPMJMI22C1,and JPMJMI22E2)Japan Science and Technology Agency,SPRING(JPMJSP2124)+3 种基金New Energy and Industrial Technology Development Organization,Green InnovationJapan Society for the Promotion of Science,Grants-in-Aid for Scientific Research(24K01325)University of Tsukuba,Organization for the Promotion of Strategic Research Initiativessupport from Japan Society for the Promotion of Science,KAKENHI(JP20H00387).
文摘Tin-based perovskite solar cells(PSCs)are the most promising alternatives to toxic lead-based ones.However,the loss in open-circuit voltage(V_(OC))remains an important issue.Improvement of V_(OC)has been achieved by using a fullerene derivative,indene-C_(60)bisadduct(ICBA),as the electron transporting layer(ETL).For further V_(OC)improvement,the V_(OC)improvement mechanisms must be clarified.Herein,we show,at a molecular level,V_(OC)improvement mechanisms by an ICBA ETL in tinbased PSCs.Electron spin resonance spectroscopy reveals that electron diffusion from perovskite to ETL occurs at perovskite/ETL interfaces,producing unfavorable upward band-bending of perovskite.Employing ICBA with a shallower LUMO level suppresses the upward band-bending as well as reduces the energy offset with the conduction band minimum of perovskite.Suppressing this unfavorable upward band-bending reduces interface recombination at perovskite/ETL interfaces and contributes to V_(OC)improvement.These insights support efficient optimization of the chargetransporting layer for additional improvement of V_(OC).
