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Exploiting Singlet Fission in Organic Light‐Emitting Diodes
Author(s) -
Nagata Ryo,
Nakanotani Hajime,
Potscavage William J.,
Adachi Chihaya
Publication year - 2018
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201801484
Subject(s) - electroluminescence , rubrene , materials science , singlet fission , oled , optoelectronics , exciton , singlet state , quantum efficiency , light emitting diode , atomic physics , physics , excited state , nanotechnology , condensed matter physics , layer (electronics)
Harvesting of both triplets and singlets yields electroluminescence quantum efficiencies of nearly 100% in organic light‐emitting diodes (OLEDs), but the production efficiency of excitons that can undergo radiative decay is theoretically limited to 100% of the electron–hole pairs. Here, breaking of this limit by exploiting singlet fission in an OLED is reported. Based on the dependence of electroluminescence intensity on an applied magnetic field, it is confirmed that triplets produced by singlet fission in a rubrene host matrix are emitted as near‐infrared (NIR) electroluminescence by erbium(III) tris(8‐hydroxyquinoline) (ErQ 3 ) after excitonic energy transfer from the “dark” triplet state of rubrene to an “emissive” state of ErQ 3 , leading to NIR electroluminescence with an overall exciton production efficiency of 100.8%. This demonstration clearly indicates that the harvesting of triplets produced by singlet fission as electroluminescence is possible even under electrical excitation, leading to an enhancement of the quantum efficiency of the OLEDs. Electroluminescence employing singlet fission provides a route toward developing high‐intensity NIR light sources, which are of particular interest for sensing, optical communications, and medical applications.