Double layer distribution exists in Cu2SnZnSe4 (CZTSe) thin films prepared by selenizing the metallic precursors, which will degrade the back contact of Mo substrate to absorber layer and thus suppressing the performance of solar cell. In this work, the double-layer distribution of CZTSe film is eliminated entirely and the formation of MoSe2 interfacial layer is inhibited successfully. CZTSe film is prepared by selenizing the precursor deposited by electrodeposition method under Se and SnSe x mixed atmosphere. It is found that the insufficient reaction between ZnSe and Cu-Sn-Se phases in the bottom of the film is the reason why the double layer distribution of CZTSe film is formed. By increasing Sn content in the metallic precursor, thus making up the loss of Sn because of the decomposition of CZTSe and facilitate the diffusion of liquid Cu2Se, the double layer distribution is eliminated entirely. The crystallization of the formed thin film is dense and the grains go through the entire film without voids. And there is no obvious MoSe2 layer formed between CZTSe and Mo. As a consequence, the series resistance of the solar cell reduces significantly to 0.14 Ω cm2 and a CZTSe solar cell with efficiency of 7.2% is fabricated.

中文翻译：

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CZTSe薄膜太阳能电池的修改后触点界面：消除吸收层中的双层分布。

通过使金属前体硒化而制备的Cu2SnZnSe4（CZTSe）薄膜中存在双层分布，这会降低Mo衬底与吸收层的背接触，从而抑制太阳能电池的性能。在这项工作中，完全消除了CZTSe膜的双层分布，并成功地抑制了MoSe2界面层的形成。CZTSe膜是通过在Se和SnSe x混合气氛下使通过电沉积方法沉积的前体硒化而制备的。发现膜底部的ZnSe和Cu-Sn-Se相之间的反应不足是形成CZTSe膜的双层分布的原因。通过增加金属前体中的Sn含量，从而弥补由于CZTSe分解而造成的Sn损失，并促进液态Cu2Se的扩散，双层分布被完全消除。所形成的薄膜的结晶是致密的，并且晶粒穿过整个薄膜而没有空隙。而且，在CZTSe和Mo之间没有形成明显的MoSe2层。结果，太阳能电池的串联电阻显着降低至0.14Ωcm2，从而制造了效率为7.2％的CZTSe太阳能电池。