This study proposes a new optimized preparation method for Cu₂ZnSnS₄ (CZTS) absorbent film. The aim is to overcome the problems faced when the conventional sol–gel method is used, which includes a smaller grain size and a small nanoparticle layer present at the bottom of the film. Our absorbent layer preparation process is divided into two cycles. In the first cycle, a low-thickness precursor film is spin-coated on molybdenum-coated soda-lime glass (SLG) and then sulfurized once. In the second cycle, the sample obtained in the first cycle is used as the substrate for spin coating, so as to obtain a second low-thickness precursor film. This is then followed by the second sulfurization process, which achieves the final absorbent layer film. Surface and cross-sectional images from the scanning electron microscope (SEM) show that the prepared absorbent layer of the film has a dense surface and CZTS large grains penetrate it in its entirety, which effectively reduces the bottom fragmented grains. It is found that under the same experimental conditions, our method increases the PCE from the traditional method’s 1.66% to 3.60%. This thereby demonstrates the feasibility of the present method to improve the quality of the absorbent layer, which in turn has a certain significance for the further improvement of the efficiency of CZTS thin-film solar cells.

本研究提出了一种新的优化制备 Cu ₂ ZnSnS _{4 的方法}(CZTS) 吸收膜。目的是克服使用传统溶胶-凝胶方法时面临的问题，包括较小的晶粒尺寸和存在于薄膜底部的小纳米颗粒层。我们的吸收层制备过程分为两个周期。在第一个循环中，将低厚度前体薄膜旋涂在钼涂层钠钙玻璃 (SLG) 上，然后硫化一次。在第二次循环中，将第一次循环得到的样品作为基材进行旋涂，得到第二层低厚度前驱体薄膜。然后是第二次硫化过程，获得最终的吸收层薄膜。扫描电子显微镜（SEM）的表面和横截面图像表明，制备的薄膜吸收层表面致密，CZTS大颗粒完全穿透，有效减少了底部碎片颗粒。发现在相同的实验条件下，我们的方法将PCE从传统方法的1.66%提高到3.60%。从而证明了本方法提高吸收层质量的可行性，对进一步提高CZTS薄膜太阳能电池的效率具有一定的意义。