i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , Suzhou 215123, China.
Department of Materials Science and Engineering, University of Washington , Seattle, Washington 98195, United States.
Nano Lett. 2017 May 10;17(5):3231-3237. doi: 10.1021/acs.nanolett.7b00847. Epub 2017 Apr 6.
Controlled doping for adjustable material polarity and charge carrier concentration is the basis of semiconductor materials and devices, and it is much more difficult to achieve in ionic semiconductors (e.g., ZnO and GaN) than in covalent semiconductors (e.g., Si and Ge), due to the high intrinsic defect density in ionic semiconductors. The organic-inorganic perovskite material, which is frenetically being researched for applications in solar cells and beyond, is also an ionic semiconductor. Here we present the Ag-incorporated organic-inorganic perovskite films and planar heterojunction solar cells. Partial substitution of Pb by Ag leads to improved film morphology, crystallinity, and carrier dynamics as well as shifted Fermi level and reduced electron concentration. Consequently, in planar heterojunction photovoltaic devices with inverted stacking structure, Ag incorporation results in an enhancement of the power conversion efficiency from 16.0% to 18.4% in MAPbI based devices and from 11.2% to 15.4% in MAPbICl based devices. Our work implies that Ag incorporation is a feasible route to adjust carrier concentrations in solution-processed perovskite materials in spite of the high concentration of intrinsic defects.
可控掺杂可调材料极性和载流子浓度是半导体材料和器件的基础，在离子半导体（如 ZnO 和 GaN）中比在共价半导体（如 Si 和 Ge）中更难实现，这是由于离子半导体中的固有缺陷密度较高。有机-无机钙钛矿材料在太阳能电池等领域的应用研究也非常活跃，它也是一种离子半导体。在这里，我们介绍了掺入 Ag 的有机-无机钙钛矿薄膜和平面异质结太阳能电池。部分 Pb 被 Ag 取代可以改善薄膜形貌、结晶度和载流子动力学，以及费米能级的移动和电子浓度的降低。因此，在具有倒置堆叠结构的平面异质结光伏器件中，Ag 的掺入可以将基于 MAPbI 的器件的功率转换效率从 16.0%提高到 18.4%，将基于 MAPbICl 的器件的功率转换效率从 11.2%提高到 15.4%。我们的工作表明，尽管存在高浓度的固有缺陷，但 Ag 掺入是一种可行的方法，可以调整溶液处理钙钛矿材料中的载流子浓度。
