The Application of Photosynthetic Materials and Architectures to Solar Cells

Abstract

Photosynthetic approaches to redesigning photovoltaics (PV) oer an attractive route towards achieving high-eciency, low-cost solar energy transduction. This thesis explores two routes toward this end: the direct integration of photosynthetic structures into solid-state devices and the architectural redesign of organic solar cells to more closely parallel photosynthesis.The highly ecient photosynthetic reaction center is the site of exciton dissociation in photosynthesis, analogous to the role of the donor-acceptor interface in organic PV. This thesis describes the successful integration of reaction centers with organic semiconductors into solid-state devices. Although functional, we nd that these devices suer the same limitation as the more traditional organic PV: the ability to absorb enough light.Photosynthetic bacteria and plants compartmentalize the processes leading to light energy conversion. This spatial separation of structures augments the evolutionary design space: the processes of photon absorption and exciton dissociation occur in two separate locations, allowing the independent functional optimization of each. Applying a similar approach to PV would similarly remove the need for multifunctional materials, bypassing limiting tradeos and permitting the utilization of new material systems. To this end, I propose a novel architecture and present initial conclusions on theoretical performance eciency. Fabricated devices demonstrate the system is viable and suggests that further improvements in device design will enable highly ecient photovoltaics.

Localized Nano-Environment for Integration and Optimum Functionalization of Chlorophyll-a Molecules

“…In a previous work [35], researchers have reported loss of spectroscopic properties when Chl-a molecules deposited as thin films were exposed directly to oxygen. As such, we have shown that by impregnating Chl-a molecules into CMC matrix forming thin films, an encapsulating effect is achieved which prolongs the optical functionality of the photosynthetic pigment.…”