Introducing a stoichiometric excess of lead iodide(PbI_(2))in perovskite films has been demonstrated as an effective passivation strategy that can improve the power conversion efficiency(PCE)of perovskite solar cells(...Introducing a stoichiometric excess of lead iodide(PbI_(2))in perovskite films has been demonstrated as an effective passivation strategy that can improve the power conversion efficiency(PCE)of perovskite solar cells(PSCs),However,excess PbI_(2)is also known to accelerate the degradation of the perovskite layer.In this study,we show that this degradation primarily stems from the decomposition of PbI_(2)at the bottom of the perovskite film which is exposed to light We further show that when using a two-step spin coating deposition procedure,the excess PbI_(2)results from the decomposition of the perovskite during the annealing process rather than the presence of non-reacted PbI_(2).Finally,we demonstrate that the spatial distribution of PbI_(2)within the perovskite films can be controlled in a way that mitigates the PbI_(2)induced perovskite decomposition.In this manner,we produced devices exhibiting initial power conversion efficiencies over 25%,maintaining 98.6% after 1000 h of maximum power point tracking under continuous illumination.These findings offer valuable insights into achieving high performance PSCs through judicious process control using a two-step spin-coating procedure.展开更多
基金funding support from the National Key R&D Program of China(2021YFF0501900)the Excellent Young Scholar Fund from the National Natural Science Foundation of China(22122903)+1 种基金the Tianjin Distinguished Young Scholar Fund(20JCJQJC00260)support from the Tianchi Talent Program of Xinjiang Uygur Autonomous Region。
文摘Introducing a stoichiometric excess of lead iodide(PbI_(2))in perovskite films has been demonstrated as an effective passivation strategy that can improve the power conversion efficiency(PCE)of perovskite solar cells(PSCs),However,excess PbI_(2)is also known to accelerate the degradation of the perovskite layer.In this study,we show that this degradation primarily stems from the decomposition of PbI_(2)at the bottom of the perovskite film which is exposed to light We further show that when using a two-step spin coating deposition procedure,the excess PbI_(2)results from the decomposition of the perovskite during the annealing process rather than the presence of non-reacted PbI_(2).Finally,we demonstrate that the spatial distribution of PbI_(2)within the perovskite films can be controlled in a way that mitigates the PbI_(2)induced perovskite decomposition.In this manner,we produced devices exhibiting initial power conversion efficiencies over 25%,maintaining 98.6% after 1000 h of maximum power point tracking under continuous illumination.These findings offer valuable insights into achieving high performance PSCs through judicious process control using a two-step spin-coating procedure.
