White Light Luminescence from a Homo‐conjugated Molecule with Thermally Activated Delayed Fluorescence

Author(s):  
Qifan YAN ◽  
Ying Zhou ◽  
Yao Li ◽  
Rong Zhang ◽  
Dahui Zhao
2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Dipjyoti Das ◽  
Peddaboodi Gopikrishna ◽  
Debasish Barman ◽  
Ramesh Babu Yathirajula ◽  
Parameswar Krishnan Iyer

Abstract White organic/polymer light emitting diode (WOLED/WPLED) processed from solution has attracted significant research interest in recent years due to their low device production cost, device flexibility, easy fabrication over large area including roll to roll and ability to print in various designs and shapes providing enormous design possibilities. Although WOLEDs fabricated using solution process lack their thermally evaporated counterparts in terms of device efficiency, remarkable progress has been made in this regard in recent years by utilizing new materials and device structures. In the present review, we have summarized and extrapolated an excellent association of old and modern concept of cost-effective materials and device structure for realization of white light. In particular, this article demonstrated and focused on design, and development of novel synthesis strategy, mechanistic insights and device engineering for solution process low cost WOLEDs device. Herein, an overview of the prevailing routes towards white light emitting devices (WLEDs) and corresponding materials used, including polymer based WLED, small molecules emitters based thermally activated delayed fluorescence (TADF), perovskite light-emitting diodes (PeLEDs) and hybrid materials based LEDs, color down-converting coatings with corresponding best efficiencies ever realized. We presume that this exhaustive review on WLEDs will offer a broad overview of the latest developments on white SSL and stonework the approach en route for innovations in the immediate future.


2019 ◽  
Vol 7 (11) ◽  
pp. 3146-3149 ◽  
Author(s):  
Yuki Kato ◽  
Hisahiro Sasabe ◽  
Yuya Hayasaka ◽  
Yuichiro Watanabe ◽  
Hiroki Arai ◽  
...  

A pyradine-containing sky blue fluorescent emitter can achieve efficient white light emission through in situ metal complex formation.


2016 ◽  
Vol 7 (3) ◽  
pp. 2201-2206 ◽  
Author(s):  
Bingjia Xu ◽  
Yingxiao Mu ◽  
Zhu Mao ◽  
Zongliang Xie ◽  
Haozhong Wu ◽  
...  

An asymmetric molecule created by molecular heredity exhibits remarkable mechanochromism and white-light emission.


2021 ◽  
Vol 12 (7) ◽  
pp. 1030-1039
Author(s):  
Praetip Khammultri ◽  
Wipaporn Kitisriworaphan ◽  
Pongsakorn Chasing ◽  
Supawadee Namuangruk ◽  
Taweesak Sudyoadsuk ◽  
...  

Conjugated TADF copolymers comprised of two TADF molecules linked with carbazole exhibited stable pure white emission from non-doped OLEDs with CIE coordinates (0.32, 0.35), a maximum luminance efficiency of 9.13 cd A−1, and a maximum EQE of 4.17%.


Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1500
Author(s):  
Gang Cheng ◽  
Dongling Zhou ◽  
Uwe Monkowius ◽  
Hartmut Yersin

Luminescent copper(I) complexes showing thermally activated delayed fluorescence (TADF) have developed to attractive emitter materials for organic light emitting diodes (OLEDs). Here, we study the brightly luminescent dimer Cu2Cl2(P∩N)2 (P∩N = diphenylphosphanyl-6-methyl-pyridine), which shows both TADF and phosphorescence at ambient temperature. A solution-processed OLED with a device structure ITO/PEDOT:PSS/PYD2: Cu2Cl2(P∩N)2/DPEPO (10 nm)/TPBi (40 nm)/LiF (1.2 nm)/Al (100 nm) shows warm white emission with moderate external quantum efficiency (EQE). Methods for EQE increase strategies are discussed.


2018 ◽  
Vol 6 (12) ◽  
pp. 2951-2956 ◽  
Author(s):  
Yongzhen Chen ◽  
Shengyong Li ◽  
Taiping Hu ◽  
Xiaofang Wei ◽  
Zhiyi Li ◽  
...  

A white LED with a bi-component light emitting layer is reported providing white light emission with a CIE of (0.38, 0.40), a CRI of 71, and a maximum EQE of 12.5%. These are among the best for bi-component based devices.


2020 ◽  
Author(s):  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
Hajime Nakanotani ◽  
Chihaya Adachi ◽  
Ken Onda

We have investigated the solvent-dependence of structural changes along with intersystem crossing of a thermally activated delayed fluorescence (TADF) molecule, 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (o-3CzBN), in toluene, tetrahydrofuran, and acetonitrile solutions using time-resolved infrared (TR-IR) spectroscopy and DFT calculations. We found that the geometries of the S1 and T1 states are very similar in all solvents though the photophysical properties mostly depend on the solvent. In addition, the time-dependent DFT calculations based on these geometries suggested that the thermally activated delayed fluorescence process of o-3CzBN is governed more by the higher-lying excited states than by the structural changes in the excited states.<br>


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