Transition metal oxides as hole-selective contacts in silicon heterojunctions solar cells
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This work reports on a comparative study comprising three transition metal oxides, MoO3, WO3 and V2O5, acting as front p-type contacts for n-type crystalline silicon heterojunction solar cells. Owing to their high work functions (>5 eV) and wide energy band gaps, these oxides act as transparent hole-selective contacts with semiconductive properties that are determined by oxygen-vacancy defects (MoO3-x), as confirmed by X-ray photoelectron spectroscopy. In the fabricated hybrid structures, 15 nm thick transition metal oxide layers were deposited by vacuum thermal evaporation. Of all three devices, the V2O5/n-silicon heterojunction performed the best with a conversion efficiency of 15.7% and an open-circuit voltage of 606 mV, followed by MoO3 (13.6%) and WO3 (12.5%). These results bring into view a new silicon heterojunction solar cell concept with advantages such as the absence of toxic dopant gases and a simplified low-temperature fabrication process.
CitationGerling Sarabia, L., Mahato, S., Morales-Vilches, A., Masmitja, G., Ortega, P., Voz, C., Alcubilla, R., Puigdollers, J. Transition metal oxides as hole-selective contacts in silicon heterojunctions solar cells. "Solar energy materials and solar cells", 2 Febrer 2016, vol. 145, núm. 2, p. 109-115.