The Biosolar Project: a Living Technology approach to photovoltaic cells Sunlight energy conversion first appeared on Earth 3,5 Bya to support Life’s energy demand by means of the photosynthesis process. Photosynthesis is the natural conversion of sunlight energy into chemical power occurring in a broad range of organisms such as plants, algae and bacteria. Photosynthesis occurs in two stages:
- In the first stage, light-dependent reactions capture the energy of light and use it to make the energy-storage molecules ATP and NADPH.
- During the second stage, the light-independent reactions use these products to capture and reduce carbon dioxide.
The light-dependent reactions cycle is our source of inspiration for the development of novel organic photovoltaics. In the light-dependent reactions, one molecule of the pigment chlorophyll absorbs one photon and loses one electron. This electron is passed to a modified form of chlorophyll called pheophytin, which passes the electron to a quinone molecule, allowing the start of a flow of electrons down an electron transport chain that leads to the ultimate reduction of NADP to NADPH. In addition, this creates a proton gradient across the chloroplast membrane; its dissipation is used by ATP synthase for the concomitant synthesis of ATP. Not all wavelengths of light can support photosynthesis. The photosynthetic action spectrum depends on the type of accessory pigments present. For example, in green plants, the action spectrum resembles the absorption spectrum for chlorophylls and carotenoids with peaks for violet-blue and red light. In red algae, the action spectrum overlaps with the absorption spectrum of phycobilins for blue- green light, which allows these algae to grow in deeper waters that filter out the longer wavelengths used by green plants. Most organisms that utilize photosynthesis to produce oxygen use visible light to do so, although at least three use infrared radiation (3). The rationale is to refactoring the photosynthesis process in order to exploit the unmatched light absorbing capability of natural pigments to increase conversion efficiency by means of broaden spectrum absorption Our approach at exploiting multiple chromofores to broaden energy absorption based on a combination of natural dyes embedded onto hydrophobic matrix to enhance charge separation. This challenging task requires a complex blend of interdisciplinary approaches ranging from organic chemistry and biochemistry to nanoscience supported by mathematical modeling and statistics to cope with the inherent complexity of the system.
EDISON - ECLT joint research project
Last update: 15/10/2019