吸收层及缓冲层厚度对Cu_(3)BiS_(3)太阳能电池的性能影响

Effects of thickness of absorption layer and buffer layer on the performance of Cu_(3)BiS_(3) solar cell

三元硫化物半导体Cu3BiS3的组成元素在地壳中含量丰富、无毒,且具有优异的光电性能,被认为是一种极具潜力的太阳能电池吸收层材料。目前关于Cu3BiS3太阳能电池器件的研究报道还非常少,在器件结构设计与制作工艺方面有一系列亟待解决的关键科学问题。文章分别通过溶液旋涂的层数及化学浴沉积时间来调控Cu3BiS3吸收层与CdS缓冲层薄膜厚度,详细分析了吸收层及缓冲层厚度对太阳能电池器件的影响规律及机制。结果表明,吸收层厚度的增加能够使光的吸收增强,使短路电流密度JSC增大,进而提高光电转换效率;然而吸收层厚度过高,会造成器件效率的下降。缓冲层厚度的增加,有利于提高器件的开路电压VOC;缓冲层过厚,同样造成器件短路电流密度的减小以及效率的下降。实验中器件的较优光电转换效率为0.288%,对应的开路电压、短路电流密度、填充因子分别为0.215 V,2.292 mA/cm2,48.049%。

Ternary chalcogenide semiconductor Cu3BiS3 has been perceived as a potential candidate of solar absorber materials in recent years,due to the low-toxic and earth-abundant component elements,and excellent optoelectronic properties.Nonetheless,sporadic investigations on Cu3BiS3 solar cell devices have been reported.There are lots of key scientific problems in structure design and manufacture process of photovoltaic device urgently need to be solved.In this paper,we adjusted the thickness of absorption layer and buffer layer through the spin-coating cycle and deposition time of chemical bath,respectively.Then,the effects of thickness of absorption and buffer layer on the performance of Cu3BiS3 solar cell were systematically analyzed.The results show that,increasing the thickness of absorption layer will enhance the light absorption and short-circuit current density(JSC),consequently improve the conversion efficiency.However,too thick film will cause the decline of device efficiency.Increasing the thickness of buffer layer is beneficial to the open-circuit voltage(VOC).Similarly,too thick film will bring about the decrease of JSC and device efficiency.The best device efficiency of 0.288%was obtained in our experiments.The corresponding VOC,JSC and fill factor(FF)values are 215 mV,2.292 mA/cm2 and 48.049%,respectively.