All-Solution-Processed Cu2ZnSnS4 Solar Cells with Self-Depleted Na2S Back Contact Modification Layer
All-Solution-Processed Cu2ZnSnS4 Solar Cells with Self-Depleted Na2S Back Contact Modification Layer
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DOI：
10.1002/adfm.201703369
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发表时间：
2018-04-05
影响因子：
19
通讯作者：
Lin, Hong
中科院分区：
文献类型：
--
作者：
Gu, Youchen;Shen, Heping;Lin, Hong
薄膜光伏材料Cu 2 ZnSnS 4（CZTS）由于其丰富的地球资源、无毒的元素组成和优异的光伏性能，近年来受到了世界各国的广泛关注。虽然现有技术的功率转换效率是通过基于肼的方法实现的，但是仍然高度期望以高产量、环境友好的方式制造这种器件的努力。本文首次采用球磨CZTS作为光吸收剂，低温溶液处理ZnO电子传输层和银纳米线透明电极，制备了无肼全溶液处理的具有Na 2S自耗尽背接触修饰层的CZTS太阳能电池。Na 2S自耗尽层的插入有效地稳定了CZTS/Mo界面，消除了CZTS与Mo包覆的钠钙玻璃之间的有害相分离反应，从而提高了CZTS光吸收层的结晶度，增强了CZTS/Mo界面的载流子输运，减小了串联电阻。此外，Na 2S改性层的自耗尽特征也避免了器件内的空穴传输势垒。结果表明界面工程对这些CZST器件至关重要，Na 2S界面层可以扩展到其他使用Mo接触的光电器件。
The thin-film photovoltaic material Cu2ZnSnS4 (CZTS) has drawn worldwide attention in recent years due to its earth-abundant, nontoxic element constitution, and remarkable photovoltaic performance. Although state-of-the-art power conversion efficiency is achieved by hydrazine-based methods, effort to fabricate such devices in a high throughput, environmental-friendly way is still highly desired. Here a hydrazine-free all-solution-processed CZTS solar cell with Na2S self-depleted back contact modification layer for the first time is demonstrated, using a ball-milled CZTS as light absorber, low-temperature solution-processed ZnO electron-transport layer as well as silver-nanowire transparent electrode. The inserting of Na2S self-depleted layer is proven to effectively stabilize the CZTS/Mo interface by eliminating a detrimental phase segregation reaction between CZTS and Mo-coated soda lime glass, thus leading to a better crystallinity of CZTS light absorbing layer, enhanced carrier transportation at CZTS/Mo interface as well as a smaller series resistance. Furthermore, the self-depletion feature of the Na2S modification layer also averts hole-transportation barrier within the devices. The results show the vital importance of interfacial engineering for these CZST devices and the Na2S interface layer can be extended to other optoelectronic devices using Mo contact.