Wang Youwei, Zhang Yubo, Zhu Haiming, Liu Jianjun, Lian Tianquan, Zhang Wenqing
State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China.
Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
Nanoscale. 2016 Apr 7;8(13):7318-25. doi: 10.1039/c5nr08934d.
We proposed a geometry strategy to engineer the radiative recombination possibility and thus the lifetime of excitons in nanowires of some photovoltaic semiconductors by using theoretical analysis and first-principles calculations. We demonstrated that the shape can engineer the symmetry of the wave-functions of band-edge states and influence the radiative recombination possibility. The nanowires need to satisfy the following requirements to forbid the radiative recombination possibility of band-edge excitons: (i) wurtzite structure; (ii) pxy-characterized wave-function of VBM state and (iii) C3v-symmetry shape. The geometrical symmetry results in the pxy-characterized C3v-symmetry wave-function of VBM state and leads to forbidden radiative recombination of band-edge excitons. The geometry strategy offers a flexible proposal to prolong the exciton lifetime, leaving optical absorption impregnable.
我们通过理论分析和第一性原理计算，提出了一种几何策略，用于设计某些光伏半导体纳米线中的辐射复合可能性，进而设计激子寿命。我们证明，形状可以设计带边态波函数的对称性，并影响辐射复合可能性。纳米线需要满足以下要求，以抑制带边激子的辐射复合可能性：（i）纤锌矿结构；（ii）价带顶（VBM）态的pxy特征波函数；（iii）C3v对称形状。几何对称性导致了价带顶态具有pxy特征的C3v对称波函数，并导致带边激子的辐射复合被抑制。这种几何策略为延长激子寿命提供了一种灵活的方案，同时保持光吸收不受影响。
