Research Progress on Triarylmethyl Radical-Based High-Efficiency OLED

Abstract

Perchlorotrityl radical (PTM), tris (2,4,6-trichlorophenyl) methyl radical (TTM), (3,5-dichloro-4-pyridyl) bis (2,4,6 trichlorophenyl) methyl radical (PyBTM), (N-carbazolyl) bis (2,4,6-trichlorophenyl) methyl radical (CzBTM), and their derivatives are stable organic radicals that exhibit light emissions at room temperature. Since these triarylmethyl radicals have an unpaired electron, their electron spins at the lowest excited state and ground state are both doublets, and the transition from the lowest excited state to the ground state does not pose the problem of a spin-forbidden reaction. When used as OLED layers, these triarylmethyl radicals exhibit unique light-emitting properties, which can increase the theoretical upper limit of the OLED’s internal quantum efficiency (IQE) to 100%. In recent years, research on the luminescent properties of triarylmethyl radicals has attracted increasing attention. In this review, recent developments in these triarylmethyl radicals and their derivatives in OLED devices are introduced.

Near-infrared organic light-emitting materials, devices and applications

“…By exploiting all excitons, the IQE of materials can reach a maximum of 100%. [49][50][51] Therefore, phosphorescent materials have emerged as the research focus of NIR luminescent materials.…”

Stable Spiro‐Fused Diarylaminyl Radicals: A New Type of a Neutral Mixed‐Valence System

“…[2] These issues are important in complex biophysical processes such as photosynthesis as well as in artificial electronic devices based on organic conjugated materials. Organic MV compounds are efficient hole-transporting materials in organic light-emitting diodes (OLEDs), [3] solar cells, [4] photochromic windows, [5] they can be used for the design of quantum-dot cellular automata, [6] etc.…”

Rationalization and tuning of doublet emission in organic radicals

“…8 The practical demonstration of radical-based OLEDs with doublet emission paved the way for the development of novel luminescent neutral radicals and OLED device architecture optimization. [9][10][11] So far, the chemical space has been principally limited to the TTM, 12 perchlorotriphenylmethyl (PTM) 13 and bis(2,4,6-trichlorophenyl)methyl (BTM) [14][15][16] radical families. Recently, Li and co-workers reported what is to date the most efficient radical-based OLED (TTM-3NCz), reaching an impressive external quantum efficiency (EQE) of 27%.…”