On the influence of partial shading and the use of bypass diodes on perovskite-based single-junction photovoltaic mini-modules

Partial shading poses a significant challenge to the stability of metal halide perovskite solar modules. In solar modules based on serial connection of solar cells, partial shading of the solar module can force shaded solar cells to operate under reverse bias voltages, which might lead to a degradation of the shaded solar cells and therefore also of the whole solar module. Metal halide perovskite solar cells are very sensitive to reverse bias voltages, making partial shading a critical issue for the related solar modules. Bypass diodes connected to each solar cell offer a potential solution to mitigate this problem. We investigated the impact of partial shading on mini-modules comprising two serially connected triple-cation metal halide perovskite single-junction solar cells. The performance of the mini-modules and their individual solar cells was compared before and after partial shading to quantify its influence. Experiments were conducted with and without a bypass diode connected to each individual solar cell. Results revealed power conversion efficiency ( PCE ) degradation of both shaded and non-shaded solar cells, at which the degradation of the shaded solar cell is significantly more pronounced, especially in the absence of a bypass diode, where an average PCE drop of 96 % was observed for the shaded solar cells. The use of bypass diodes, which limited in our case the reverse bias voltage across the shaded solar cells to about −0.2 V, reduced the average PCE drop of the shaded solar cell from 96 % to 34 %, which is still a significant degradation.