A novel bioinspired quantum photocell based on GaN quantum dots

Abstract

The efficiency of classical photocells is restricted by Shockley–Queisser limit and radiative recombination is one of the key contributors in efficiency degradation. Recent experiments on photosynthetic apparatus of plants and bacteria have suggested that these systems can overcome this limitation by exploiting excitonic quantum coherence. In photosynthetic apparatus, solar photons create excitons in the pigment protein molecules. These excitons are then transferred to the reaction centre where charge separation takes place. These processes – excitonic generation and subsequent charge separation – are extremely efficient with almost unity efficiency and avoid efficiency degradation due to radiative recombination. Taking a cue from this biophysical process, we propose a GaN quantum dot-based quantum photocell that emulates the photosynthetic reaction centre. The proposed photocell uses delocalised excitons to exhibit efficiency larger than its classical counterpart. This further suggests that highly efficient quantum biological processes can give important pointers for developing energy harvesting quantum technologies.