在N型PERT太阳电池制备过程中,蒸镀铝可作为太阳电池背面的金属电极,但是由于背面激光开膜所引起的氧化层会影响太阳电池的串联电阻(R_s),所以必须在蒸镀铝工序完成后对太阳电池进行退火处理以减少Rs。文章重点研究了以蒸镀铝为背电极的N型PERT太阳电池在不同退火工艺下的性能差异,研究结果表明,退火温度不变,随着退火时间的增加,Rs逐渐降低,填充因子(FF)和短路电流密度(J_(sc))迅速升高,开路电压(V_(oc))则缓慢升高,如果退火时间恰当,R_s会降得很低,V_(oc)也会处于峰值,此时电池效率(E_(ta))最大,最终在退火温度为380℃,且退火时间为40 s时,太阳电池的E_(ta)可达到20.77%。通过研究发现:太阳电池的退火过程可用阿伦尼乌斯公式来表达,通过此方程得出了铝和氧化硅退火反应的表观活化能为91.89 k J/mol。
In the preparation process of N-type PERT solar cells, evaporated aluminum can serve as the metallization at the back of the cell. However, the oxide layer at the backside caused by laser ablation of the passivation layer could significantly impact the series resistance of solar cells through an annealing process after aluminum evaporation to reduce the series resistance of the solar cells.This paper focuses on the performance variations of PERT solar cells with back evaporated aluminum under different annealing process conditions. The experimental results show that when annealing at a particular temperature, the following occur with the increase of annealing time: the series resistance of the solar cells is reduced, the fill factor and short circuit current increase rapidly, and the open-circuit voltage increases slowly. At a certain annealing time, the series resistance decreases to an extremely low level, while the open-circuit voltage remains at a peak point, and at that time the efficiency of the solar cell is the highest. As a result, a 20.77% efficiency solar cell could be obtained when the annealing temperature was 380 ℃ and the annealing time was40 s. Herein, we report that the annealing process follows an Arrhenius Equation and that an activation energy of 91.89 k J/mol for the annealing reaction was obtained using the equation.