当前位置: X-MOL 学术J. Phys. Chem. C › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Effects of Perovskite Monovalent Cation Composition on the High and Low Frequency Impedance Response of Efficient Solar Cells
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2018-01-18 00:00:00 , DOI: 10.1021/acs.jpcc.7b11010
Pengjiu Wang 1 , Maria Ulfa 1 , Thierry Pauporté 1
Affiliation  

The partial replacement of methylammonium by formamidinium and cesium in organolead trihalide materials is of great importance to improve the performance and stability of photovoltaic solar cells. However, the effect of multiple cations on the cell functioning and their electrical characteristics remains to be clarified. By using the impedance spectroscopy technique, we have investigated the electrical response to a small ac perturbation applied to solar cells implementing hybrid perovskites with various compositions, polarized over a large potential range. The solar cell preparation protocols have been optimized to reach power conversion efficiencies higher than 17%. The impedance response has been investigated both under light and in the dark to discriminate the light sensitive parameters. The spectra have been carefully analyzed using an ad hoc equivalent circuit, and the data have been discussed in the light of the existing literature. The spectra showed no intermediate frequency inductive loop due to the absence of multistep charge transfer involving surface states. A large inductive loop is found to be the signature of poorly functioning solar cells. Except for the high frequency capacitance, which is the bulk response of perovskite, the other parameters are influenced by interface and contact phenomena, ionic conductivity and charge accumulations. The scaling of the low frequency capacitance with the hysteresis amplitude is clearly stated by our comprehensive study. Moreover, no diffusion impedance due to the diffusion of ionic species is observed. However, ion mobility results in a strong effect on recombinations and has a strong influence on the low frequency impedance response of the system.

中文翻译:

钙钛矿单价阳离子组成对高效太阳能电池高频和低频阻抗响应的影响

在三卤化有机铅材料中用甲酰胺和铯部分取代甲基铵对于提高光伏太阳能电池的性能和稳定性非常重要。但是,多种阳离子对细胞功能及其电学特性的影响尚待阐明。通过使用阻抗光谱技术,我们研究了对小交流电扰动的电响应,该交流电应用于实施具有各种成分,在大电位范围内极化的混合钙钛矿的太阳能电池。太阳能电池制备方案已经过优化,可实现高于17%的功率转换效率。已经在明暗情况下研究了阻抗响应,以区分光敏参数。光谱已使用特别指定等效电路,并且已经根据现有文献讨论了数据。由于不存在涉及表面状态的多步电荷转移,光谱显示没有中频感应环路。发现大的感应环路是功能差的太阳能电池的标志。除了高频电容(钙钛矿的整体响应)外,其他参数还受界面和接触现象,离子电导率和电荷积累的影响。我们的综合研究清楚地表明了低频电容随磁滞幅度的变化。此外,未观察到由于离子种类的扩散而引起的扩散阻抗。然而,
更新日期:2018-01-18
down
wechat
bug