Cu-X(X=B, Al, Ga, In)共掺杂对ZnS可见光吸收的影响

ZnS能够用于光解水制氢，但是由于ZnS带隙较宽在一定程度上制约了可见光的吸收。为了减小闪锌矿ZnS的带隙宽度，增加对可见光的吸收，采用密度泛函理论研究了Cu-X(X=B, Al, Ga, In)共掺杂对ZnS电子结构和可见光吸收的影响。计算结果表明Cu-X(X=B, Al, Ga, In)共掺杂ZnS的结合能都是负值，都属于稳定结构；掺杂使得闪锌矿ZnS的带隙宽度由2.9eV分别减小到2.68eV、2.41 eV、2.18 eV、1.82 eV，导致了吸收谱和光导产生红移，有利于可见光的吸收；掺杂后导带底向低能级方向移动，同时在禁带中产生p-d杂化能级，导致了带隙宽度减小，有利于可见光的吸收和阻止光生载流子的复合；最后掺杂ZnS的带边位置满足水解制氢的条件，可用于制造光催化剂。综上所述Cu-X(X=B, Al, Ga, In)共掺杂ZnS有利于可见光的吸收。

Effects of Cu-X (X=B, Al, Ga, In) co-doping on visible light absorption of ZnS

ZnS has been used for splitting water to produce hydrogen, however, the reaction cannot be driven by the visible light because of its wide energy band gap. In order to reduce the band gap of zinc blende ZnS and increase the absorption of visible light, the effect of Cu-X (X=B, Al, Ga, In) co-doping on the electronic structure and visible light absorption of ZnS were studied by density functional theory (DFT). Calculation results reveal that the binding energies of Cu-X (X=B, Al, Ga, In) co-doped ZnS is negative, therefore, these systems are stable. Cu-X (X=B, Al, Ga, In) co-doping reduces the band gap of zinc blende ZnS from 2.9eV to 2.68eV, 2.41 eV, 2.18 eV, and 1.82 eV, respectively, resulting in red shift of absorption spectrum and light guide, which is beneficial to visible light absorption. Co-doping shift the bottom of the conduction band toward the lower energy level, and introduce a p-d hybridization level in the forbidden band, resulting in a decrease of the band gap, which is beneficial to the absorption of visible light and prevention of photo-generated carrier recombination. Moreover, band edge positions of co-doped ZnS are suitable for water splitting to generate hydrogen, and will be candidate materials for water splitting driven by visible light. In general, Cu-X (X=B, Al, Ga, In) co-doped ZnS is beneficial to the absorption of visible light.