TRITON Controlling Wavefunction Overlap for Triplet Energy Transfer in Organic/Nanocrystal Quantum Dots Hybrids

Summary

The generation, control and transfer of triplet excitons in molecular and hybrid systems is of great interest for optoelectronic applications such as light emission, singlet fission, up/down-conversion and photovoltaics. While coupling triplet excitons from inorganic QDs to organic molecules has been well demonstrated, the reverse process, the transfer of triplets from organic semiconductors to QDs is much more challenging and the underlying reasons are still unclear to the field. Recently, the host group has demonstrated that it is possible to transfer triplet excitons from molecular acenes to emissive nanocrystal quantum dots (QDs). This allows the direct conversion of dark triplet excitons to photons in the hybrids. As triplets generation yield through singlet fission in acene molecules can be up to 200%, this discovery opens a new avenue for highly efficient down-conversion. However, the exact factors that govern the transfer, especially the role of interfaces between the two components, remains unknown. The project will build on the host group’s discovery to develop the fundamental science of this new hybrids platform for optoelectronics. Specifically, we will develop a series of highly controlled solution/solid phase systems, where the interfacial conditions of the hybrid will be intentionally modified. The surface ligands, passivation, energy states of the QDs and the distance to the molecules will be precisely controlled. The molecules will also be covalently attached to the QD surface by a range of functional groups. These systems will be studied with steady-state and time-resolved spectroscopies with the aim of elucidating the underlying mechanism controlling the wavefunction overlap and triplet exciton transfer in the hybrids. We will also conduct proof of concept experiments to demonstrate the use of the optimised hybrid materials for down-convertor. These fundamental investigations will open up new possibilities for down-conversion and optoelectronics.

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Web resources:	https://cordis.europa.eu/project/id/842271
Start date:	01-04-2019
End date:	31-03-2021
Total budget - Public funding:	224 933,76 Euro - 224 933,00 Euro