步进扫描时间分辨光谱及其在太阳电池光电导上的应用

Step scan time resolved spectroscopy and its application to photoconductivity of Si solar cells

建立傅里叶变换步进扫描时间分辨光电导光谱 ,并研究太阳电池中与转换效率密切相关的少数载流子寿命 .实验选取三种典型的硅太阳电池 (单晶硅样品 1、多晶硅样品 2和多晶硅样品 3) ,发现其瞬态光电导的上升和衰退曲线可以分别用两个简单的指数函数描述 .由于有复合中心的参与 ,复合过程中少数载流子的寿命比产生过程中的寿命短 .为验证实验结果的可靠性 ,采用了提取样品少数载流子的体寿命和计算其有效扩散长度两种方法 .通过与太阳电池暗伏安特性和负载特性研究相结合 ,进一步分析和讨论了少数载流子寿命与短路电流、开路电压和转换效率的关系 .

We report on the establishment of Fourier transform step-scan time-resolved photoconductivity spectroscopy to study the solar cell's minority carrier lifetime,which has close relationship with its conversion efficiency.Three typical Si solar cells are selected in our experiments,including both the monocrystalline and polycrystalline silicon samples.We find that the rise and decay curves of the transient photoconductivity can be well described by two simple exponential functions.Due to the participation of recombination centers,the recombination minority carrier lifetimes are generally smaller than those of generation.In order to prove the reliability of our experimental results,we extract the bulk lifetime and the effective diffusion length of the three samples.Furthermore,we analyze the correlation of the minority lifetime with the short-circuit current,open voltage and conversion efficiency,by the aid of the investigation of solar cells' dark I-V characteristics and load characteristics.In addition,we also discuss in detail other applications of the established step-scan time-resolved spectroscopy.