Seminar with prof. Prof. Dr. Andy Monkman – 27/April/2016 – 14 horas
THE PHYSICS GRADUATE PROGRAM invites everyone to the seminar:
Reaching 100% efficient OLEDs. Converting triplet excitons into singlet states without spin orbit coupling
Prof. Dr. Andy Monkman
Organic Electroactive Materials Research Group
Department of Physics, Durham University, England
Abstract:
Organic light emitting diodes are now a common place technology, but increasing their internal efficiency to near 100% is difficult. The main reason for this is that on charge recombination, 75% of excited states formed have triplet character and are non emissive. At present iridium containing phosphors are used to harvest these states to produced light, but a new type of emitter has been developed that can also convert triplet to singlet states but without the need for a heavy metal or spin orbit coupling, Thermally Activated Delay Fluorescence; ‘TADF’. In my talk I will describe the mechanisms that drive TADF and show how molecular design and careful energy level tuning give rise to 22% external quantum efficiency deep blue OLEDs. Throughout, new time resolved photophysical measurements will be explained and used to elucidate the physics behind TADF.
Date: 27/April/2016 – (wednesday) – Place: Sala 212 – Auditório do Departamento de Física – Time: 14 horas
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