Transparent bifacial a-Si:H solar cells employing silver oxide embedded transparent rear electrodes for improved transparency

Abstract We developed a transparent oxide–metal–oxide (OMO) structure using aluminum-doped zinc oxide and oxidized silver (AgO x ) as a transparent electrode of a hydrogenated amorphous silicon (a-Si:H) thin-film solar cell for use in building-integrated photovoltaic (BIPV) windows. The oxygen (O 2 ) addition (O 2 flow rate) was optimized for a metal-to-dielectric intermediate-phase AgO x OMO to have high transparency and high conductivity, which were confirmed by finite-difference time-domain simulation. Using the AgO x OMO as a rear electrode, transparent a-Si:H solar cells were fabricated for BIPV window application. The performance of the fabricated cells showed highest bifacial efficiency (b- η ) of 7.87% at AgO x OMO of 1 sccm, and highest average transmittance ( T 500–800 , i.e., wavelength range: 500–800 nm) of 21.9% at AgO x OMO of 3 sccm, i.e., improvements from b- η  = 7.42% and T 500–800  = 18.8% at Ag OMO of 0 sccm. The cell with the optimized AgO x OMO (3 sccm) achieved b- η  = 7.69% and the best figure of merit (product of b- η and T 500–800 ) of 169%, i.e., 30% higher than the Ag OMO cell (139%). The developed AgO x OMO electrodes could be used in BIPV windows or in other optical devices requiring both high transparency and high conductivity.