As single junction photovoltaic (PV) technologies both Si heterojunction (HIT) and perovskite based solar cells promise high efficiencies at low cost. Intuitively a traditional tandem cell design with these cells connected in series is expected to improve the efficiency further. Using a self-consistent numerical modeling of optical and transport characteristics however we find that a traditional series connected tandem design suffers from low JSC due to band-gap mismatch and current matching constraints. Specifically a traditional tandem cell with state-of-the-art HIT ( η=24% ) and perovskite ( η=20% ) sub-cells provides only a modest tandem efficiency of ηT~ 25%. Instead we demonstrate that a bifacial HIT/perovskite tandem design decouples the optoelectronic constraints and provides an innovative path for extraordinary efficiencies. In the bifacial configuration the same state-of-the-art sub-cells achieve a normalized output of η∗T = 33% exceeding the bifacial HIT performance at practical albedo reflections. Unlike the traditional design this bifacial design is relatively insensitive to perovskite thickness variations which may translate to simpler manufacture and higher yield.
Solar Cell, Tandem, Perovskite, Silicon Heterojunction
Date of this Version
Bifacial Si heterojunction-perovskite organic-inorganic tandem to produce highly efficient (ηT* ∼ 33%) solar cell Asadpour, Reza and Chavali, Raghu V. K. and Ryyan Khan, M. and Alam, Muhammad A., Applied Physics Letters, 106, 243902 (2015), DOI:http://dx.doi.org/10.1063/1.4922375