High Performance p- and n-Type Light-Emitting Field-Effect Transistors Employing Thermally Activated Delayed Fluorescence

Jan Sobus, Fatima Bencheikh, Masashi Mamada, Robert Wawrzinek, Jean Charles Ribierre, Chihaya Adachi, Shih Chun Lo, Ebinazar B. Namdas

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Light-emitting field-effect transistors (LEFETs) are an emerging type of devices that combine light-emitting properties with logical switching function. One of the factors limiting their efficiency stems from the spin statistics of electrically generated excitons. Only 25% of them, short lived singlet states, are capable of light emission, with the other 75% being long lived triplet states that are wasted as heat due to spin-forbidden processes. Traditionally, the way to overcome this limitation is to use phosphorescent materials as additional emission channel harnessing the triplet excitons. Here, an alternative strategy for triplet usage in LEFETs in the form of thermally activated delayed fluorescence (TADF) is presented. Devices employing a TADF capable material, 4CzIPN (2,4,5,6-tetra[9H-carbazol-9-yl]isophthalonitrile), in both n-type and p-type configurations are shown. They manifest excellent electrical characteristics, consistent brightness in the range of 100–1,000 cd m-2 and external quantum efficiency (EQE) of up to 0.1%, which is comparable to the equivalent organic light-emitting diode (OLED) based on the same materials. Simulation identifies the poor light out-coupling as the main reason for lower than expected EQEs. Transmission measurements show it can be partially alleviated using a more transparent top contact, however more structural optimization is needed to tap the full potential of the device.

Original languageEnglish
Article number1800340
JournalAdvanced Functional Materials
Volume28
Issue number28
DOIs
Publication statusPublished - Jul 11 2018

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Field effect transistors
field effect transistors
Fluorescence
fluorescence
Excitons
excitons
Switching functions
Structural optimization
Light emission
taps
Organic light emitting diodes (OLED)
Quantum efficiency
stems
atomic energy levels
light emission
quantum efficiency
Luminance
emerging
brightness
light emitting diodes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Condensed Matter Physics
  • Electrochemistry

Cite this

High Performance p- and n-Type Light-Emitting Field-Effect Transistors Employing Thermally Activated Delayed Fluorescence. / Sobus, Jan; Bencheikh, Fatima; Mamada, Masashi; Wawrzinek, Robert; Ribierre, Jean Charles; Adachi, Chihaya; Lo, Shih Chun; Namdas, Ebinazar B.

In: Advanced Functional Materials, Vol. 28, No. 28, 1800340, 11.07.2018.

Research output: Contribution to journalArticle

Sobus, Jan ; Bencheikh, Fatima ; Mamada, Masashi ; Wawrzinek, Robert ; Ribierre, Jean Charles ; Adachi, Chihaya ; Lo, Shih Chun ; Namdas, Ebinazar B. / High Performance p- and n-Type Light-Emitting Field-Effect Transistors Employing Thermally Activated Delayed Fluorescence. In: Advanced Functional Materials. 2018 ; Vol. 28, No. 28.
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