Energy level engineering of charge selective contact and halide perovskite by modulating band offset:Mechanistic insights

• 作者: Yassine Raoui Hamid Ez-Zahraouy Samrana Kazim Shahzada Ahmad
• 来源期刊: 能源化学
• 年，卷（期）: 2021,（3）
• 页码范围: 822-829
• 页数: 8页
• 语种: 英文

摘要

Mixed cation and anion based perovskites solar cells exhibited enhanced stability under outdoor condi-tions,however,it yielded limited power conversion efficiency when Ti02 and Spiro-OMeTAD were employed as electron and hole transport layer(ETL/HTL)respectively.The inevitable interfacial recombi-nation of charge carriers at ETL/perovskite and perovskite/HTL interface diminished the efficiency in pla-nar(n-i-p)perovskite solar cells.By employing computational approach for uni-dimensional device simulator,the effect of band offset on charge recombination at both interfaces was investigated.We noted that it acquired cliff structure when the conduction band minimum of the ETL was lower than that of the perovskite,and thus maximized interfacial recombination.However,if the conduction band min-imum of ETL is higher than perovskite,a spike structure is formed,which improve the performance of solar cell.An optimum value of conduction band offset allows to reach performance of 25.21％,with an open circuit voltage(Voc)of 1231 mV,a current density Jsc of 24.57 mA/cm2 and a fill factor of 83.28％.Additionally,we found that beyond the optimum offset value,large spike structure could decrease the performance.With an optimized energy level of Spiro-OMeTAD and the thickness of mixed-perovskite layer performance of 26.56％can be attained.Our results demonstrate a detailed understanding about the energy level tuning between the charge selective layers and perovskite and how the improvement in PV performance can be achieved by adjusting the energy level offset.