Shin Dongguen, Kang Donghee, Jeong Junkyeong, Park Soohyung, Kim Minju, Lee Hyunbok, Yi Yeonjin
Institute of Physics and Applied Physics, Yonsei University , 50 Yonsei-ro, Seodaemun-Gu, Seoul 03722, Republic of Korea.
Department of Physics, Kangwon National University , 1 Gangwondaehak-gil, Chuncheon-si, Gangwon-do 24341, Republic of Korea.
J Phys Chem Lett. 2017 Nov 2;8(21):5423-5429. doi: 10.1021/acs.jpclett.7b02562. Epub 2017 Oct 24.
In organolead halide perovskite solar cells (PSCs), interfacial properties between the perovskite and charge transport layers are the critical factors governing charge extraction efficiency. In this study, the effect of interfacial energetics between two-step spin-coated methylammonium lead iodide (MAPbI) with different methylammonium iodide (MAI) concentrations and C on the charge extraction efficiency is investigated. The electronic structures of perovskite films are significantly varied by the MAI concentrations due to the changes in the residual precursor and MA defect content. As compared to the optimum PSCs with 25 mg mL MAI, PSCs with other MAI concentrations show significantly lower power conversion efficiencies and severe hysteresis. The energy level alignment at the C/MAPbI interface determined by ultraviolet and inverse photoelectron spectroscopy measurements reveals the origin of distinct differences in device performances. The conduction band offset at the C/MAPbI interface plays a crucial role in efficient charge extraction in PSCs.
在有机铅卤化物钙钛矿太阳能电池（PSC）中，钙钛矿与电荷传输层之间的界面性质是决定电荷提取效率的关键因素。在本研究中，研究了不同碘化甲铵（MAI）浓度的两步旋涂碘化甲铵铅（MAPbI）与碳之间的界面能量对电荷提取效率的影响。由于残余前驱体和MA缺陷含量的变化，钙钛矿薄膜的电子结构因MAI浓度而显著不同。与含25 mg/mL MAI的最佳PSC相比，其他MAI浓度的PSC显示出显著更低的功率转换效率和严重的滞后现象。通过紫外和逆光电子能谱测量确定的C/MAPbI界面处的能级排列揭示了器件性能明显差异的根源。C/MAPbI界面处的导带偏移在PSC的有效电荷提取中起着关键作用。
