Design and Characterization of Inverted Singlet and Triplet Excited States with Organic Radicals (DECOR)

The exchange of energy between p-conjugated molecules and light underpins current and future technologies for displays from light-emitting diodes, electricity generation in solar cells, bioimaging and photochemical production. These applications require molecules to transition between different excited energy states within a manifold of levels. The ‘normal’ ordering of molecules set the first excited states to have weak light absorption and emission properties, forming (triplet) states that are detrimental for these applications by lowering their efficiency.
In this proposal we explore ‘inverted’ molecules – working against ‘normal’ expectations from quantum mechanics (Hund's rules) to solve this problem – where now the first excited states (singlet) exhibit strong light absorption and emission. By coupling these molecules to stable radicals with unpaired electron states we enable magnetic characterization of ‘normal’ vs ‘inverted’ order of levels. We will explore new opportunities in upconversion that converts lower energy states to higher energy: demonstrating the potential to get more energy and work done from less in future applications. This project will push the boundaries of spin and optical properties of advanced molecular materials for energy management with potential future applications in more efficient and sustainable energy generation and consumption (UN SDG 7: Affordable and Clean Energy; UN SDG 11: Sustainable Cities and Communities), as well as photocatalysis in production of fine chemicals and pharmaceuticals (UN SDG 12: Responsible Consumption and Production).
The programme is enabled by two leading early-career researchers from the UK (Evans) and Japan (Aizawa) with complementary expertise in molecular materials design, characterization and exploitation.