Simple excited-state modification toward a deep-blue hybridized local and charge-transfer (HLCT) fluorophore and non-doped organic light-emitting diodes

Abstract

Realizing high-performance deep-blue fluorophores and non-doped organic light-emitting diodes (OLEDs) with the Commission international de I'Eclairage (CIE) coordinate of CIEy < 0.046 is important and challenging task for the wide...

A Breakthrough in Color‐Tunable All‐Fluorescent White OLEDs through the Cooperation Between a New Blue HLCT Fluorophore and a Long‐Wavelength TADF Emitter

“…As illustrated in Figure 1b, the optimized ground state geometry of PICZ2F presents a moderately twisted molecular conformation where the torsion angles of 37.34° and 35.53° between p ‐difluorobenzene and adjacent benzene moieties. In comparison to the compound 9,9′‐(2′,5′‐difluoro‐[1,1′:4′,1′’‐terphenyl]−4,4′’‐diyl)bis(9 H ‐carbazole) with symmetric 9‐phenylcarbazole units, [ 16 ] PICZ2F exhibits a lower torsion angle of 25.38° between the phenanthrimidazole moiety and the adjacent benzene group. This could potentially enhance fluorescence efficiency and charge transport.…”

Simple and efficient non-doped deep-blue and white organic light-emitting diode based on hybridized local and charge transfer (HLCT) materials

“…Most HLCT materials for OLEDs do not involve complicated doping technology, which is conducive to simplifying device structure and improving device yield. 19,20…”

A record-high EQE of 7.65%@3300 cd m−2 achieved in non-doped near-ultraviolet OLEDs based on novel D′–D–A type bipolar fluorophores upon molecular configuration engineering

“…11,12 Although some efforts have been made via rational molecular design or device engineering, external quantum efficiencies (EQEs) usually lie below 7% in simple non-doped NUV-OLEDs. 3,13–28 Moreover, most of the NUV-OLEDs suffer from serious efficiency roll-off at a high luminance level and poor color purity (the full width at half maximum (FWHM) value exceeding 50 nm), due to the intermolecular aggregation, strong intramolecular charge transfer (CT) effect, and unbalanced carrier injection, transport, and recombination.…”