Improvement in the light conversion efficiency of silicon solar cells by pure hydrogen annealing

In this report, the effects of pure hydrogen gas annealing on series resistance (Rs), shunt resistance (Rsh), open circuit voltage (Voc), short circuit current (Isc), fill factor, and efficiency were investigated systematically using standard, commercially available polysilicon solar cells. Improvements on the electrical characteristics, fill factors, and efficiency of the solar cells were observed after annealing by pure hydrogen gas at 350 °C for 15 min. In the best case, the conversion efficiency was raised by nearly 1% point. Judging from our experimental evidences, the improvement on cell performance could be mostly attributed to the reduction of Rs and improvement in Ag grid/emitter contact resistance in the cells during the annealing process.