Enhancing bio-photovoltaic cell efficiency: A study in transport property

Recently, bio-solar cells have garnered significant attention owing to their relatively high efficiency and cost-effectiveness, positioning them as alternative devices for solar energy harvesting. This study delves into the optical and electrical transport characteristics of a novel bilayer bio-solar cell using the total system transfer matrix method, theoretically. These bilayer bio-solar cells consist of two distinct layers of Chlorophyll-a and Chlorophyll-b, forming a heterojunction in the bio-solar cell architecture. Within these solar cells, photon absorption by the active layers of chlorophyll generates excitons and quasi-particles (bound electron and hole pairs), which subsequently diffuse through the collecting layer, resulting in significant recombination losses. The influence of the thickness of chlorophyll adsorbent active layers on the short circuit current density and quantum efficiency is examined through numerical calculations. Furthermore, we develop models for the solar cell parameters of thin film heterojunction photovoltaic devices based on Chlorophyll-a/Chlorophyll-b. The results indicate efficient short circuit current and quantum efficiency values (or power conversion efficiency) of 72 A/m2 and 3.30%, respectively. It is demonstrated that optimizing the thickness of bio-solar cells based on these findings may enhance electron transport, leading to higher photocurrents and improved overall efficiency. These simulation outcomes pave the way for optimizing the thickness of bio-solar cells and advancing towards higher efficiencies.