Bifacial Si Heterojunction-Perovskite Organic-Inorganic Tandem to Produce Highly Efficient Solar Cell

TL;DR

This paper proposes a bifacial HIT/Perovskite tandem solar cell design that overcomes traditional efficiency limitations, achieving higher efficiencies and manufacturing robustness through decoupling optoelectronic constraints.

Contribution

It introduces a bifacial tandem configuration that significantly improves efficiency and simplifies manufacturing compared to traditional series-connected designs.

Findings

Bifacial HIT/Perovskite tandem exceeds 33% efficiency.

Traditional tandem design achieves only ~25% efficiency.

Bifacial design is less sensitive to Perovskite thickness variations.

Abstract

As single junction thin-film technologies, both Si heterojunction (HIT) and Perovskite based solar cells promise high efficiencies at low cost. One expects that a tandem cell design with these cells connected in series will 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. It requires careful thickness optimization of Perovskite to achieve any noticeable efficiency gain. Specifically, a traditional tandem cell with state-of-the-art HIT (24%) and Perovskite (20%) sub-cells provides only a modest tandem efficiency of ~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 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.