Journal of Physics: Materials ( IF 5.847 ) Pub Date : 2021-05-11 , DOI: 10.1088/2515-7639/abfa7b Andrea Ruiz-Perona 1 , Yudania Snchez 2 , Maxim Guc 2 , Tim Kodalle 3 , Marcel Placidi 2, 4 , Jos Manuel Merino 1 , Ftima Cabello 5 , Marina Garca-Pardo 5 , Mximo Len 1 , Raquel Caballero 1
Semi-transparent solar cells are the next step for photovoltaics into our daily life. Over the last years, kesterite-type material has attracted a special attention to be used as an absorber in thin-film solar cells because of its low toxicity and earth abundant constituents. Here, Cu2ZnGeSe4 (CZGSe) thin films are grown by co-evaporation and subsequent annealing at a maximum temperature of 480 C or 525 C onto Mo/V2O5/FTO/glass stacks. The goal of this work is to investigate the influence of the annealing temperature on the composition, morphology, vibrational properties, and transmittance of CZGSe layers, the formation of secondary phases, and distribution of elements within the absorber layer as well as on the optoelectronic properties of the corresponding solar cell devices. Raising the annealing temperature to 525 C leads to a more uniform distribution of Cu, Zn, Ge and Se throughout the absorber layer, a reduction of the presence of the GeSe2 secondary phase, which is mainly detected at 480 C, a larger grain size and the formation of a thicker MoSe2 layer at the CZGSe/back contact interface. The strategy of increasing the annealing temperature allows for improved J–V characteristics and higher spectral response resulting in an enhanced device performance of 5.3% compared to 4.2% when using 525 C and 480 C, respectively. Both absorber layers present an optical band gap energy of 1.47 eV. Furthermore, higher annealing temperature has beneficial effect to the CZGSe-based devices without losses in total transmitted light because of the higher diffuse transmittance. This work shows first promising semi-transparent CZGSe-based solar cells possibly open up new routes of applications.
中文翻译:
退火温度对透明基板上生长的Cu 2 ZnGeSe 4薄膜和太阳能电池的影响
半透明太阳能电池是光伏进入我们日常生活的下一步。在过去的几年里,黄铜矿型材料因其低毒性和丰富的地球成分而引起了特别关注,用作薄膜太阳能电池中的吸收剂。在这里,Cu 2 ZnGeSe 4 (CZGSe) 薄膜通过共蒸发和随后在 480 摄氏度或 525 摄氏度的最高温度下退火到 Mo/V 2 O 5上生长/FTO/玻璃栈。这项工作的目的是研究退火温度对 CZGSe 层的成分、形态、振动特性和透射率、第二相的形成、吸收层内元素分布以及光电特性的影响相应的太阳能电池器件。将退火温度提高到 525 C 会导致 Cu、Zn、Ge 和 Se 在整个吸收层中的分布更均匀,GeSe 2第二相的存在减少,主要在 480 C 下检测到,更大的晶粒尺寸以及在 CZGSe/背接触界面处形成较厚的 MoSe 2层。提高退火温度的策略可以改善J –V特性和更高的光谱响应使器件性能提高了 5.3%,而在使用 525 C 和 480 C 时分别提高了 4.2%。两个吸收层都具有 1.47 eV 的光学带隙能量。此外,由于较高的漫透射率,较高的退火温度对基于 CZGSe 的器件具有有益影响,而不会损失总透射光。这项工作表明,首个有前景的半透明 CZGSe 基太阳能电池可能开辟新的应用途径。