Alternative n-type buffer layer such as In 2 S 3 has been proposed as a Cd-free alternative in kesterite Cu 2 ZnSn ( S , Se ) 4 (CZTSSe) solar cells. In this study, optical and electronic characterization techniques together with device analysis and simulation were used to assess nanoparticle-based CZTSSe absorbers and solar cells with CdS and In 2 S 3 buffers. Photoluminescence spectroscopy indicated that CZTSSe absorbers with In 2 S 3 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 In 2 S 3 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 In 2 S 3 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.

中文翻译：

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使用 In2S3 缓冲层的 Cu2ZnSn(S,Se)4 太阳能电池的缺陷限制

替代的 n 型缓冲层如 In 2 S 3 已被提议作为黄铜矿 Cu 2 ZnSn ( S , Se ) 4 (CZTSSe) 太阳能电池中的无镉替代物。在这项研究中，光学和电子表征技术以及器件分析和模拟被用于评估基于纳米颗粒的 CZTSSe 吸收剂和具有 CdS 和 In 2 S 3 缓冲液的太阳能电池。光致发光光谱表明，与具有 CdS 缓冲液的吸收剂相比，具有 In 2 S 3 缓冲液的 CZTSSe 吸收剂具有较低密度的有害非辐射缺陷和较高浓度的铜空位 V Cu +，这在 CZTSSe 中负责 p 型导电性. 电容-电压 (C-V) 测量表明，与具有 CdS 层的器件相比，基于 In 2 S 3 缓冲器的 CZTSSe 器件的表观掺杂密度高出三倍，因此空间电荷区更窄。这导致近红外区域光生载流子的收集较差，尽管 X 射线光电子和逆光电子能谱确定了更有利的能带排列。与具有 CdS 的参考器件相比，由 C-V 和偏置量子效率测量确定的 In 2 S 3 器件中界面缺陷状态的存在也是造成开路电压损失的原因。这导致近红外区域光生载流子的收集较差，尽管 X 射线光电子和逆光电子能谱确定了更有利的能带排列。与具有 CdS 的参考器件相比，由 C-V 和偏置量子效率测量确定的 In 2 S 3 器件中界面缺陷状态的存在也是造成开路电压损失的原因。这导致近红外区域光生载流子的收集较差，尽管 X 射线光电子和逆光电子能谱确定了更有利的能带排列。与具有 CdS 的参考器件相比，由 C-V 和偏置量子效率测量确定的 In 2 S 3 器件中界面缺陷状态的存在也是造成开路电压损失的原因。