Effect of Li<sup>+</sup> Doping on Photoelectric Properties of Double Perovskite Cs<sub>2</sub>SnI<sub>6</sub>: First Principles Calculation and Experimental Investigation
Jin Zhang,
Chen Yang,
Yulong Liao,
Shijie Li,
Pengfei Yang,
Yingxue Xi,
Weiguo Liu,
Dmitriy A. Golosov,
Sergey M. Zavadski,
Sergei N. Melnikov
Affiliations
Jin Zhang
Shaanxi Province Key Laboratory of Thin Films Technology and Optical Test, School of Optoelectronic Engineering, Xi’an Technological University, Xi’an 710032, China
Chen Yang
Shaanxi Province Key Laboratory of Thin Films Technology and Optical Test, School of Optoelectronic Engineering, Xi’an Technological University, Xi’an 710032, China
Yulong Liao
State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology, Chengdu 610054, China
Shijie Li
Shaanxi Province Key Laboratory of Thin Films Technology and Optical Test, School of Optoelectronic Engineering, Xi’an Technological University, Xi’an 710032, China
Pengfei Yang
Shaanxi Province Key Laboratory of Thin Films Technology and Optical Test, School of Optoelectronic Engineering, Xi’an Technological University, Xi’an 710032, China
Yingxue Xi
Shaanxi Province Key Laboratory of Thin Films Technology and Optical Test, School of Optoelectronic Engineering, Xi’an Technological University, Xi’an 710032, China
Weiguo Liu
Shaanxi Province Key Laboratory of Thin Films Technology and Optical Test, School of Optoelectronic Engineering, Xi’an Technological University, Xi’an 710032, China
Dmitriy A. Golosov
Center 9.1 “Electronic Technologies and Engineering Diagnostics of Process Media and Solid State Structures” R&D Department, Belarusian State University of Informatics and Radioelectronics, 220013 Minsk, Belarus
Sergey M. Zavadski
Center 9.1 “Electronic Technologies and Engineering Diagnostics of Process Media and Solid State Structures” R&D Department, Belarusian State University of Informatics and Radioelectronics, 220013 Minsk, Belarus
Sergei N. Melnikov
Center 9.1 “Electronic Technologies and Engineering Diagnostics of Process Media and Solid State Structures” R&D Department, Belarusian State University of Informatics and Radioelectronics, 220013 Minsk, Belarus
Double perovskite Cs2SnI6 and its doping products (with SnI2, SnF2 or organic lithium salts added) have been utilized as p-type hole transport materials for perovskite and dye-sensitized solar cells in many pieces of research, where the mechanism for producing p-type Cs2SnI6 is rarely reported. In this paper, the mechanism of forming p-type Li+ doped Cs2SnI6 was revealed by first-principles simulation. The simulation results show that Li+ entered the Cs2SnI6 lattice by interstitial doping to form strong interaction between Li+ and I−, resulting in the splitting of the α spin-orbital of I–p at the top of the valence band, with the intermediate energy levels created and the absorption edge redshifted. The experimental results confirmed that Li+ doping neither changed the crystal phase of Cs2SnI6, nor introduced impurities. The Hall effect test results of Li+ doped Cs2SnI6 thin film samples showed that Li+ doping transformed Cs2SnI6 into a p-type semiconductor, and substantially promoted its carrier mobility (356.6 cm2/Vs), making it an ideal hole transport material.
