Pseudohalide induced tunable electronic and excitonic properties in two-dimensional single-layer perovskite for photovoltaics and photoelectronic applications  

作　　者：Zhuo Xu Ming Chen Shengzhong(Frank)Liu 

机构地区：[1]Key Laboratory of Applied Surface and Colloid Chemistry, National Ministry of Education, Shaanxi Normal University,Xi'an 710119, Shaanxi, China [2]Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Normal University,Xi'an 710119, Shaanxi, China [3]Shaanxi Engineering Lab for Advanced Energy Technology, Institute for Advanced Energy Materials, Shaanxi Normal University,Xi'an 710119, Shaanxi, China [4]School of Materials Science and Engineering, Shaanxi Normal University,Xi'an 710119, Shaanxi, China [5]iChEM, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China [6]University of the Chinese Academy of Sciences,Beijing 100039, China

出　　处：《Journal of Energy Chemistry》2019年第9期106-113,共8页能源化学（英文版）

基　　金：funded by the National Key Research and Development Program of China (2017YFA0204800/2016YFA0202403);the Fundamental Research Funds for the Central Universities (2018CBLZ006);the National Natural Science Foundation of China (61604091 and 61674098);the 111 Project (B14041);the Changjiang Scholar and Innovative Research Team (IRT_14R33);the Chinese National 1000 Talents Plan program (1110010341);the China Postdoctoral Science foundation (2018M633455);the Fundamental Research Funds for the Central Universities (GK201903055)

摘　　要：Two-dimensional(2D) layered organic-inorganic hybrid perovskites have attracted much more attention for some applications than their three-dimensional(3D) perovskite counterparts due to their promising thermal and moisture stabilities.In particular, the 2D perovskite devices have shown better promise for optoelectronic applications.However, tunability of optoelectronic properties is often demanded to improve the device performance.Herein, we adopt a newly method to tune the electronic properties of 2D perovskite by introducing pseudohalide into the structure.In this work, we designed a pseudohalidesubstituted 2D perovskite by substituting the out-of-plane halide with pseudohalide and studied the electronic and excitonic properties of 2D-BA2MX4 and 2D-BA2MX2Ps2(M=Ge^(2+), Sn^(2+), and Pb^(2+);X=I;Ps=NCO, NCS, OCN, SCN, Se CN).We revealed the dependence of electronic properties including band gaps, composition of band edges, bonding characteristics, work functions, effective masses, and exciton binding energies on different pseudohalides substituted in 2D perovskite.Our results indicate that the substitution of pseudohalide in 2D perovskites is energetically favorable and can significantly affect the bonding characteristics as well as the CBM and VBM that often play major role in determining their performance in optoelectronic devices.It is expected that the pseudohalide substitution will be helpful in developing more advanced optoelectronic device based on 2D perovskite by optimizing band alignment and promoting charge extraction.Two-dimensional（2D） layered organic-inorganic hybrid perovskites have attracted much more attention for some applications than their three-dimensional（3D） perovskite counterparts due to their promising thermal and moisture stabilities.In particular, the 2D perovskite devices have shown better promise for optoelectronic applications.However, tunability of optoelectronic properties is often demanded to improve the device performance.Herein, we adopt a newly method to tune the electronic properties of 2D perovskite by introducing pseudohalide into the structure.In this work, we designed a pseudohalidesubstituted 2D perovskite by substituting the out-of-plane halide with pseudohalide and studied the electronic and excitonic properties of 2D-BA2MX4 and 2D-BA2MX2Ps2(M=Ge2+, Sn2+, and Pb2+; X=I;Ps=NCO, NCS, OCN, SCN, Se CN).We revealed the dependence of electronic properties including band gaps, composition of band edges, bonding characteristics, work functions, effective masses, and exciton binding energies on different pseudohalides substituted in 2D perovskite.Our results indicate that the substitution of pseudohalide in 2D perovskites is energetically favorable and can significantly affect the bonding characteristics as well as the CBM and VBM that often play major role in determining their performance in optoelectronic devices.It is expected that the pseudohalide substitution will be helpful in developing more advanced optoelectronic device based on 2D perovskite by optimizing band alignment and promoting charge extraction.

关 键 词：Two-dimensional perovskites Pseudohalides Density functional theory Electronic and excitonic properties 

分 类 号：O4[理学—物理]