Defect limitations in Cu2ZnSn(S, Se)4 solar cells utilizing an In2S3 buffer layer
Defect limitations in Cu2ZnSn(S, Se)4 solar cells utilizing an In2S3 buffer layer
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DOI：
10.1063/5.0002372
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发表时间：
2020-05-29
影响因子：
3.2
通讯作者：
Zoppi, Guillaume
中科院分区：
文献类型：
--
作者：
Campbell, Stephen;Qu, Yongtao;Zoppi, Guillaume
另一种n型缓冲层，如In2S3，已被提出作为一种无Cd替代物用于方锌矿Cu2ZnSn(S，Se)(4)(CZTSSe)太阳电池。在这项研究中，利用光学和电学表征技术，结合器件分析和模拟，评估了基于纳米颗粒的CZTSSe吸收材料和带有CdS和In2S3缓冲层的太阳能电池。光致发光光谱表明，含In2S3缓冲层的CZTSSe吸收体中有害的非辐射缺陷密度较低，而导致CZTSSe中p型电导的铜空位V-Cu(+)浓度较高。电容-电压(C-V)测量表明，基于In2S3缓冲层的CZTSSe器件具有比具有CDS层的器件高三倍的表观掺杂密度和更窄的空间电荷区。这导致了在近红外区对光生载流子的收集较差，尽管X射线光电子能谱和逆光电子能谱确定了更有利的能带排列。由C-V和偏置量子效率测量确定的In2S3器件中界面缺陷态的存在也是导致开路电压损失的原因。
Alternative n-type buffer layer such as In2S3 has been proposed as a Cd-free alternative in kesterite Cu2ZnSn(S, Se)(4) (CZTSSe) solar cells. In this study, optical and electronic characterization techniques together with device analysis and simulation were used to assess nanoparticlebased CZTSSe absorbers and solar cells with CdS and In2S3 buffers. Photoluminescence spectroscopy indicated that CZTSSe absorbers with In2S3 buffer had a lower density of detrimental non-radiative defects and a higher concentration of copper vacancies V-Cu(+), responsible for p-type conductivity in CZTSSe, in comparison to the absorber with CdS buffer. Capacitance-voltage (C-V) measurements revealed that the In2S3 buffer-based CZTSSe devices had a three times higher apparent doping density and a consequently narrower space charge region than devices with a CdS layer. This resulted in poorer collection of photo-generated charge carriers in the near-IR region despite a more favorable band alignment as determined by x-ray photoelectron and inverse photoelectron spectroscopy. The presence of interfacial defect states in In2S3 devices as determined by C-V and biased quantum efficiency measurements is also responsible for the loss in open-circuit voltage compared with reference devices with CdS.