Consideration on open-circuit voltage of Si heterojunction solar cells under low concentration condition

We conducted a one-dimensional device simulation of Si heterojunction low-concentrator solar cells using AFORSHET focusing on the influence of Auger recombination on the open-circuit voltage. It was found that the influence of Auger recombination becomes apparent at approximately 10-30 suns. We measured the properties under concentration of prototype heterojunction solar cells and compared the theoretical and experimental results. The open-circuit voltage at 1 sun was 0.72 V, but increased to 0.77 V at 12 suns. In addition to the characterization with solar simulators, the relation between incident light intensity and Voc was measured using a Suns-Voc apparatus. As a result, a Voc of 0.81-0.82 V was obtained at around 30 suns.