Cu(InGa)Se2 (CIGS) solar cells become one of the most important thin film photovoltaic devices thus far. The doping of Sb has improved the grain size of CIGS thin film and therefore led to the enhancement of solar cell efficiency. Various approaches have been used for the Sb doping. Not many reports of electrodeposition of In, Ga and Sb alloy have been reported. In this work, the Sb thin film was coated over Cu film surface prior to the In and Ga deposition in order to form a Cu/Sb/In/Ga metal precursor. After selenization, the Sb doped CIGS film was prepared. The structure and morphology of Sb doped CIGS films were investigated compared with the undoped CIGS reference samples. A modified selenization method was proposed, which improved the grain size. Finally, the conversion efficiency of Sb doped CIGS based solar cells has been improved by 1.02%.

Based on the density functional theory with hybrid functional approach, we calculated the structural, electronic, and the optical properties of Cu₂MgSn(S_1-xSe_x)₄ (CMTSSe)，an potential photovoltaic material for thin film solar cells. The calculation reveals a phase transition from kesterite to stannite structure when Zn atoms are substituted by Mg atoms. In particular, the S-to-Se ratio can determine the energy splitting between the electronic states at the top of the valence band. The band gaps of CMTSSe can be tuned in the ranges of 1.01—1.58 eV. Calculated optical properties and tunable band gaps make them beneficial for achieving band-gap-graded solar cells.

采用共蒸发法在不同衬底温度下沉积Cu2ZnSnSe4（简称CZTSe)薄膜, 分析了衬底温度对CZTSe材料性质及电池性能的影响。研究表明: 当衬底温度较低时（380 ℃), CZTSe薄膜中含有SnSex使电池失效; 随着衬底温度的升高, CZTSe薄膜的结晶质量明显提升, 电池开路电压增加。但当衬底温度达到460 ℃时, 电池的转换效率反而下降; 结合CZTSe的生长机理及器件模型分析了电池效率下降可能的原因。最终在衬底温度420 ℃的条件下制备出效率为3.12%（有效面积0.34 cm2)的CZTSe太阳电池。

Cu2ZnSnSe4 (CZTSe) absorbers were deposited on borosilicate glass substrate using the low-temperature process, and different Na incorporation methods were applied to investigate the effects of Na on the CZTSe growth. Na was dif-fused into some of the absorbers after growth, which led to strongly improved device performance compared with Na-free cells. With the post-deposition treatment, the effect of Na on CZTSe growth was excluded, and most of Na was expected to reside at grain boundaries. The conversion efficiency of the completed device was improved due to the enhancement of open circuit voltage and fill factor. The efficiency of 2.85% was achieved at substrate temperature as low as 420 ℃.

This paper provides the fabrication of Cd-free Cu(In,Ga)Se₂(CIGS) solar cells on soda-lime glass substrates. A high quality ZnS buffer layer is grown by chemical bath deposition (CBD) process with ZnSO₄-NH₃-SC (NH₂)₂aqueous solution system. The X-ray diffraction (XRD) result shows that the as-deposited ZnS film has cubic (111) and (220) diffraction peaks. Scanning electron microscope (SEM) images indicate that the ZnS film has a dense and compact surface with good crystalline quality. Transmission measurement shows that the optical transmittance is about 90% when the wavelength is beyond 500 nm. The bandgap (Eg) value of the as-deposited ZnS film is estimated to be 3.54 eV. Finally, a competitive efficiency of 11.06% is demonstrated for the Cd-free CIGS solar cells with ZnS buffer layer after light soaking.