22.5% efficient silicon heterojunction solar cell with molybdenum oxide hole collector
Jonas Geissbühler, Jérémie Werner, Silvia Martin de Nicolas, Loris Barraud, Aïcha Hessler-Wyser, Matthieu Despeisse, Sylvain Nicolay, Andrea Tomasi, Bjoern Niesen, Stefaan De Wolf, Christophe Ballif
Substituting the doped amorphous silicon films at the front of silicon heterojunction solar cells with wide-bandgap transition metal oxides can mitigate parasitic light absorption losses. This was recently proven by replacing p-type amorphous silicon with molybdenum oxide films. In this article, we evidence that annealing above 130 °C—often needed for the curing of printed metal contacts—detrimentally impacts hole collection of such devices. We circumvent this issue by using electrodeposited copper front metallization and demonstrate a silicon heterojunction solar cell with molybdenum oxide hole collector, featuring a fill factor value higher than 80% and certified energy conversion efficiency of 22.5%.
Appl. Phys. Lett. 107, 081601 (2015)