Sun Yali, Qiu Pengfei, Yu Wei, Li Jianjun, Guo Hongling, Wu Li, Luo Hao, Meng Rutao, Zhang Yi, Liu Shengzhong Frank
Institute of Photoelectronic Thin Film Devices and Technology of Nankai University, Tianjin Key Laboratory of Thin Film Devices and Technology, Engineering Research Center of Thin Film Photoelectronic Technology, Tianjin, 300350, China.
College of Physics Science and Technology, Hebei University, Baoding, 071002, China.
Adv Mater. 2021 Dec;33(49):e2104330. doi: 10.1002/adma.202104330. Epub 2021 Oct 8.
As a low-cost substitute that uses no expensive rare-earth elements for the high-efficiency Cu(In,Ga)(S,Se) solar cell, the Cu ZnSn(S,Se) (CZTSSe) solar cell has borrowed optimization strategies used for its predecessor to improve its device performance, including a profiled band gap and surface inversion. Indeed, there have been few reports of constructing CZTSSe absorber layers with surface inversion to improve efficiency. Here, a strategy that designs the CZTSSe absorber to attain surface modification by using n-type Ag ZnSnS is demonstrated. It has been discovered that Ag plays two major roles in the kesterite thin film devices: surface inversion and front gradient distribution. It has not only an excellent carrier transport effect and reduced probability of electron-hole recombination but also results in increased carrier separation by increasing the width of the depletion region, leading to much improved V and J . Finally, a champion CZTSSe solar cell renders efficiency as high as 12.55%, one of the highest for its type, with the open-circuit voltage deficit reduced to as low as 0.306 V (63.2% Shockley-Queisser limit). The band engineering for surface modification of the absorber and high efficiency achieved here shine a new light on the future of the CZTSSe solar cell.
作为一种用于高效铜铟镓硫硒（Cu(In,Ga)(S,Se)）太阳能电池的低成本替代物，且不使用昂贵的稀土元素，铜锌锡硫硒（Cu ZnSn(S,Se)，CZTSSe）太阳能电池借鉴了其前身所采用的优化策略来提升器件性能，包括能带分布优化和表面反型。实际上，关于构建具有表面反型的CZTSSe吸收层以提高效率的报道很少。在此，展示了一种通过使用n型Ag ZnSnS来设计CZTSSe吸收体以实现表面改性的策略。已发现Ag在硫锡铜矿薄膜器件中起两个主要作用：表面反型和前沿梯度分布。它不仅具有出色的载流子传输效果并降低了电子 - 空穴复合概率，还通过增加耗尽区宽度导致载流子分离增加，从而使开路电压（V）和短路电流密度（J）得到显著改善。最终，一个性能最佳的CZTSSe太阳能电池实现了高达12.55%的效率，这在同类电池中处于最高水平之一，开路电压损失降低至低至0.306 V（达到肖克利 - 奎伊瑟极限的63.2%）。此处实现的吸收体表面改性的能带工程以及高效性能为CZTSSe太阳能电池的未来发展指明了新方向。
