A5074709732- Organic Light-Emitting Diodes Research
- Organic Electronics and Photovoltaics
- Luminescence and Fluorescent Materials
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Molecular Junctions and Nanostructures
- Conducting polymers and applications
- Perovskite Materials and Applications
- Carbon and Quantum Dots Applications
- Thin-Film Transistor Technologies
- Photonic Crystals and Applications
Seoul National University
2017-2023
Government of the Republic of Korea
2020
University of Seoul
2020
We report three highly efficient multiresonance thermally activated delayed fluorescence blue-emitter host materials that include 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene (DOBNA) and tetraphenylsilyl groups. The doped with the conventional N7,N7,N13,N13,5,9,11,15-octaphenyl-5,9,11,15-tetrahydro-5,9,11,15-tetraaza-19b,20b-diboradinaphtho[3,2,1-de:1',2',3'-jk]pentacene-7,13-diamine (ν-DABNA) blue emitter exhibit a high photoluminescence quantum yield greater than 0.82, horizontal...
A series of indolo[3,2-b]indole (IDID) derivatives are designed as a novel structural platform for thermally activated delayed fluorescence (TADF) emitters. Intramolecular charge transfer (ICT)-type molecules consisting IDID donor (D) and various acceptor (A) moieties synthesized characterized in the protocol systematical structure-property correlation. exhibit high efficiency, prompt well TADF with emission ranges tuned by chemical structure units. Interestingly, almost all show an...
With the rise of all-organic light-emitting diode (OLED) technology, understanding complex phenomenon known as “heavy-atom effect” (HAE) is becoming increasingly important. The ability abundant heavy atoms (HAs)...
Abstract A molecular structural approach is applied by introducing substituent groups (X) to explore the structure–property correlation of thermally activated delayed fluorescence (TADF) mechanism and develop blue TADF materials. D–A–X emitters show emissions from 446 487 nm exhibit high rate constants reverse intersystem crossing ( k rISC ) 0.76 × 10 6 2.13 s −1 . Organic light emitting diodes (OLEDs) based on efficient external quantum efficiency 17.2% 23.9%. Furthermore, theoretical...
Abstract Four crucifix‐shaped molecules, named TPA‐BPSB, DMAc‐BPSB, MTPA‐BPSB and MDMAc‐BPSB, bearing the same acceptor fragment of bis(phenylsulfonyl)benzene (BPSB) different donor segments (TPA MTPA are diphenylamine derivatives while DMAc MDMAc 9,9‐dimethylacridine derivatives) synthesized characterized by NMR, mass spectra, single crystal X‐ray crystallography. The molecular structure–property relationship these molecules is systematically explored. All compounds display thermally...
Abstract A pure red‐emitting organic light‐emitting transistor (OLET) is successfully fabricated using a π‐extended dicyanodistyrylbenzene‐type semiconductor material (Hex‐4‐TFPTA), which shows outstanding charge transport and solid‐state luminescence at the same time. Based on structural (X‐ray) photophysical analyses, it found that appropriate molecular stacking highly allowed S 1 →S 0 transition of Hex‐4‐TFPTA created ambidextrous balance between electrical mobility ( µ e, FET ≈ cm 2 V −1...
A series of twisted triaryl-<italic>s</italic>-triazine derivatives are used as acceptor fragments in design deep-blue TADF emitters for OLED. Comprehensive photophysical investigations indicate high impact structural relaxation on the color and efficiency.
Charge-transfer (CT) crystals show unique transport and emission properties which are substantially different from those of individual electron donor (D) acceptor (A) molecules constituting them. While the CT well established as to enable interpretation prediction their electrical properties, photophysical processes—particularly emission–structure relationship in crystals—are much less explored; this is because often weak photoluminescence (PL), attributed small oscillator strength (f)...
Three dicyanostyrylbenzene (DCS)-based small-molecule nonfullerene acceptors (SM-NFAs), NIDCS-MO, NIDCS-PrO, and NIDCS-PeO, bearing alkoxy chains with different lengths from methoxy to pentyloxy are synthesized investigate the alkyl chain length effect on performance of all-small-molecule organic solar cells (SM-OSCs). The optical properties frontier molecular orbital (FMO) energy levels three SM-NFAs virtually identical in both solution neat films. In contrast, their photovoltaic SM-OSCs a...
In the search of organic materials with high energies lowest excited states for application in highly demanded blue OLEDs, we discovered a tunability triplet state localized on phenyl-s-triazines (3LE) by substitution at s-triazine. A widely used three-state model thermally activated delayed fluorescence (TADF) suggests key role energetic closeness 3LE and charge-transfer (1CT 3CT) achieving fast reverse intersystem crossing (rISC) external quantum efficiency (EQE) OLEDs. Following this...
During the last few years, phenomenon of thermally activated delayed fluorescence (TADF) finds more and applications in numerous fields technology, especially organic light emitting diodes (OLED) giving rise to variously shaped flexible optoelectronic devices displays. Further development products using OLED technology requires emitters exhibiting deep-blue TADF with relatively short emission lifetimes high chemical stability. The state-of-the-art pure comprise donor acceptor fragments...
It is strongly believed that further progress in organic light emitting technologies depends on if we can develop heavy-metal-free materials with fast reverse intersystem crossing (rISC) and fluorescence rates subnanosecond domain. Nowadays, the most promising uprising all-organic OLED including those using thermally activated delayed (TADF) phenomenon TADF combined Förster resonance energy transfer (FRET), a so-called "hyperfluorescence", rely donor-acceptor fastest rISC. However,...