Li Yujiao, Li Chen, Yu Huanqin, Yuan Beilei, Xu Fan, Wei Haoming, Cao Bingqiang
School of Physics and Physical Engineering, Qufu Normal University, Qufu, China.
School of Materials Science and Engineering, University of Jinan, Jinan, China.
Front Chem. 2020 Oct 7;8:754. doi: 10.3389/fchem.2020.00754. eCollection 2020.
To regulate the optical and electrical properties of the crystals and films of the intrinsic methylammonium lead iodide (CHNHPbI), we dope them with sodium (Na) by selecting sodium iodide (NaI) as a dopant source. The highly conductive p-type sodium-doped CHNHPbI (MAPbI: Na) perovskite single crystals and thin films are successfully grown using the inverse temperature crystallization (ITC) method and antisolvent spin-coating (ASC) method, respectively. With the increase of Na doping concentration, the grain size of the film increases, the surface becomes smoother, and the crystallinity improves. Hall effect results demonstrate that both the MAPbI: Na thin films and single crystals change their quasi-insulating intrinsic conductivity to a highly conductive p-type conductivity. The room-temperature photoluminescence (PL) peaks of doped MAPbI films slightly blue shift, while the photocarriers' lifetime becomes longer. The optical fingerprints of the doped levels in MAPbI: Na perovskites can be identified by temperature-dependent PL. Obvious fingerprints of Na-related acceptor (AX) levels in the doped MAPbI: Na were observed at 10 K. These results suggest that sodium doping is an effective way to grow highly conductive p-type MAPbI perovskites.
为了调控本征甲基碘化铵铅（CH₃NH₃PbI₃）晶体和薄膜的光学与电学性质，我们通过选择碘化钠（NaI）作为掺杂源，用钠（Na）对其进行掺杂。分别采用逆温结晶（ITC）法和反溶剂旋涂（ASC）法成功生长出了高导电p型钠掺杂CH₃NH₃PbI₃（MAPbI₃:Na）钙钛矿单晶和薄膜。随着Na掺杂浓度的增加，薄膜的晶粒尺寸增大，表面变得更光滑，结晶度提高。霍尔效应结果表明，MAPbI₃:Na薄膜和单晶均将其准绝缘本征电导率转变为高导电p型电导率。掺杂MAPbI₃薄膜的室温光致发光（PL）峰略有蓝移，而光载流子寿命变长。MAPbI₃:Na钙钛矿中掺杂能级的光学特征可通过变温PL来识别。在10 K时观察到掺杂MAPbI₃:Na中明显的与Na相关的受主（AX）能级特征。这些结果表明，钠掺杂是生长高导电p型MAPbI₃钙钛矿的有效方法。
