Description du projet
De nouvelles molécules aromatiques génèrent des excitons à longue durée de vie pour des cellules solaires efficaces
La plupart des cellules solaires fonctionnent sur le même principe: un photon génère un exciton, un état lié d’un électron et d’un trou d’électron, qui peut être converti en électricité. Certaines molécules organiques peuvent générer deux excitons à partir d’un seul photon, augmentant ainsi la quantité d’électricité que la cellule solaire peut produire lorsqu’elle est irradiée. Un grand défi associé à ce processus de «fission du singulet» est que les molécules organiques ne sont pas stables. Par conséquent, les excitons ne vivent que très peu de temps, ce qui les rend difficiles à exploiter pour produire de l’électricité. Le projet EXAM, financé par l’UE, tirera profit de l’aromaticité (une propriété de certaines molécules organiques anormalement stables) pour concevoir des matériaux de fission de singulet stables. Cette nouvelle méthode de conception peut contribuer à augmenter l’efficacité des cellules solaires.
Objectif
Singlet exciton fission is a carrier multiplication process in organic semiconductors that generates two electron-hole pairs for one photon absorbed, affording quantum efficiencies up to 200%. Photovoltaic devices based on singlet fission have received large attention recently for their potential in efficiency enhancement and to break the Shockley-Queisser limit on the efficiency of single-junction photovoltaics. Recent advancements in singlet fission have been materials-limited due to the rarity of molecules which meet the essential energetic requirement for the process, that the energy of the lowest triplet excited state be approximately half the energy of the lowest singlet excited state. Also important is to ensure the chemical stability of the candidate compounds that would broaden their application prospect. In this proposal, we exploit the excited-state aromaticity view to manipulate the excited state energy levels and build novel singlet fission candidates. Based on theoretical and experimental study, selective models will be evaluated, synthesized and analysed, aiming at a novel strategy for manipulating the excited state energy and stability of organic semiconductors with the aromaticity view. The main aimis to demonstrate highly stable, tuneable organic materials which undergo singlet fission through exploitation of the aromaticity of both the ground state and excited states and feasible design rules for these materials. The materials are expected to be promising candidates as singlet fission functional layer for solar cells and other multiple exciton generation applications. The result concept represents better understanding and tailoring excited state properties of organic semiconductors, which can be expended to wide range of materials with particular excited state nature for even wider application prospect.
Champ scientifique
- natural sciencesphysical scienceselectromagnetism and electronicssemiconductivity
- natural scienceschemical sciencesorganic chemistryaromatic compounds
- engineering and technologyenvironmental engineeringenergy and fuelsrenewable energysolar energyphotovoltaic
- natural sciencesphysical sciencestheoretical physicsparticle physicsphotons
Programme(s)
Régime de financement
MSCA-IF-EF-ST - Standard EFCoordinateur
CB2 1TN Cambridge
Royaume-Uni