Photonic-amplified QD@Host perovskite solar cells

Quantum dots-in-host (QD@Host) hetero-semiconductors have a set of properties of conspicuous interest for photovoltaic (PV) applications, such as photogeneration beyond the standard semiconductor bandgap absorption limit — enabling substantially broader exploitation of the solar spectrum. Nevertheless, a key aspect has remained thus far unexploited: coupling these features with advanced light-management techniques can pronouncedly improve the overall behaviour of solar cells by boosting the QDs absorption at the desired spectral range. Hence, this work studied the achievable optical benefits of optimized QD@Host absorber materials (namely PbS@Perovskite) incorporated in solar cells, and of compounding those gains with the addition of light-trapping (LT) from photonic structures. For that, a semi-classical optical method was developed, capable of exploring the addition of quantum-enabled photo-generation from the QDs in thin perovskite-based PV cells. A smart-search design optimization was then performed for both planar and photonic-enhanced solar cells. In the latter case, the objective was to maximize resonant LT to amplify the QD-generated absorption. The optimized structures revealed significant below-bandgap absorption produced via embedded QDs, without detriments to the above-bandgap absorption mainly occurring in the host perovskite, which is shown to lead to photocurrent gains reaching 30 %. Adding the LT structures managed to further increase the absorption by ∼20 % (up to 50 % total enhancement relative to the pristine cells). Remarkably, while the pristine devices photocurrent is below the standard Shockley-Queisser limit for single-bandgap cells, as expected, the LT-enhanced QD@Host solar cells managed to surpass this limit by 46 %, underlining the outstanding potential of this technology.