细致平衡理论计算CdS/CdTe异质结太阳电池的极限转换效率

DETAIL BALANCE LIMIT OF EFFICIENCY OF CdS /CdTe HETEROJUNCTION SOLAR CELLS

在细致平衡理论基础上,针对异质结电池在结处由于能带不连续而形成载流子运动势垒可能对光生载流子的运输存在阻碍作用,建立异质结太阳电池的光电转换模型,解决了细致平衡理论无法计算异质结太阳电池极限效率的问题,推导出CdS/CdTe异质结太阳电池光照下的I-V特性表达式以及最大光电转换效率的求法。指出电池的I-V特性以及最大转换效率与电池的内建势垒密切相关,并求出在理想情况AM1.5的光照下CdS/CdTe异质结太阳电池最大转换效率可达29%;考虑到CdS和CdTe的典型参数后,计算出其最大转换效率可达25%。分析了现实中电池效率不高的原因,并指出实现电池转换效率提高的可行性。

Based on detailed balance theory and considered the barriers at interface of heterojunction, which result from the band offset and block photon-generated carriers transport, a photoelectric conversion model for heterojunc- tion solar cells was established. The problem of the limit efficiency of heterojunction solar ceils was solved using the detailed balance theory. A method to realize the I-V characteristics of the CdS/CdTe heterojunction solar cells under the illumination and the limit conversion efficiency of CdS/CdTe solar cells was proposed in this article. Under the illumination, the I-V characteristics and maximum conversion efficiency are closely related to the built-in barrier of the CdS/CdTe solar cells. It is shown that a theoretical efficiency limit of 29% can be achieved for CdS/CdTe heterojunction solar cells under AM1.5 illumination. Considering the typical parameters of CdS and CdTe, the maximum conversion efficiency of 25% can be achieved. Analysis of the reality of the efficiency is not high and the feasibility of improving conversion efficiency of the CdS/CdTe heterojunction solar ceils.