p型多晶硅PERC太阳电池LeTID特性和机理的研究

热辅助光诱导衰减（LeTID）作为一种不可忽视的太阳电池效率衰减现象,其衰减机制和相关缺陷形态的演变过程亟需澄清。针对p型多晶硅钝化发射极局域接触（PERC）太阳电池,研究在不同光照强度下的衰减规律,光照促进了衰减-再生反应的进行,衰减程度随光照强度减小而增大。对衰减起主导作用的是由LeTID过程中产生的体内深能级缺陷导致的SRH复合,该缺陷中心的电子与空穴俘获截面之比k值在33~37范围内,而对衰减影响较小的浅能级缺陷可能是k值在0.1~1.0之间的Fe—B复合物。

STUDY ON KINETICS AND MECHANISM OF LeTID IN P-TYPE POLYSILICON PERC SOLAR CELL

Light and elevated temperature degradation （LeTID） is a non-negligible phenomenon of efficiency degradation in silicon solar cell. However, the exact mechanism of the degradation and the evolution process of related defect still need to be clarified. In this paper, we analyzed the evolution of degradation and regeneration under different light intensity in p-type multi-crystalline silicon passivated emitter and rear contact （PERC） solar cell. It shows that illumination accelerates the degradation and the regeneration reaction, but the decrease in light intensity improves the degradation degree. The result shows that there are two main defects inducing SRH （Shockley-Read-Hall） recombination in the bulk of silicon during the degradation-regeneration cycle. The deep level defect dominants SRH recombination in the bulk with ratio of electron to hole capture cross-sections k in the range of 33<k<37, and the shallow level defect with less influence during the whole cycle may be Fe—B complex with k value between 0.1 and 1.