Halogen-induced internal heavy-atom effect shortening the emissive lifetime and improving the fluorescence efficiency of thermally activated delayed fluorescence emitters

2017 ◽  
Vol 5 (46) ◽  
pp. 12204-12210 ◽  
Author(s):  
Yepeng Xiang ◽  
Yongbiao Zhao ◽  
Nan Xu ◽  
Shaolong Gong ◽  
Fan Ni ◽  
...  
Keyword(s):  
Electron Acceptor ◽  
Heavy Atom ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Heavy Atom Effect ◽  
Thermally Activated ◽  
Fluorescence Efficiency ◽  
Atom Effect

A halogenating electron acceptor is demonstrated as a feasible strategy for shortening emissive lifetimes while improving the fluorescence efficiency of TADF emitters.

scholarly journals Heavy-Atom Effect Promotes Multi-Resonance Thermally Activated Delayed Fluorescence

2021 ◽  
Author(s):  
Tao Hua ◽  
Lisi Zhan ◽  
Nengquan Li ◽  
Zhongyan Huang ◽  
Xiaosong Cao ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Heavy Atom ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Heavy Atom Effect ◽  
Thermally Activated ◽  
Organic Light ◽  
Atom Effect

As one type of latest emitters with simultaneous high efficiency and color-purity, the development of multi-resonance thermally activated delayed fluorescence (MR-TADF) materials represents an important advancement for organic light-emitting diodes (OLEDs). We herein present a new strategy to improve the performance of MR-TADF emitters by fusing sulfur element into the B-N based framework, aiming to utilize the non-metal heavy-atom effect in accelerating the reverse intersystem crossing (RISC) process of the emitter. Two compounds, namely 2PTZBN and 2PXZBN, were developed in this work through rigidifying the DABNA-1 skeleton by sulfur or oxygen atoms. The theoretical calculations and photoluminescence studies revealed that the sulfur-incorporated 2PTZBN enabled considerable rate constant of RISC (<i>k</i><sub>RISC</sub>) up to 2.8 × 10<sup>5</sup> s<sup>-1</sup> in toluene due to larger spin-orbital coupling (SOC) values and smaller singlet-triplet energy splitting (Δ<i>E</i><sub>ST</sub>) compared with 2PXZBN. Consequently, organic light-emitting diodes based on 2PTZBN exhibited highly efficient green emission with maximum external quantum efficiency (EQE) of 25.5%.

Heavy-Atom Effect Promotes Multi-Resonance Thermally Activated Delayed Fluorescence

2021 ◽  
pp. 131169
Author(s):  
Tao Hua ◽  
Lisi Zhan ◽  
Nengquan Li ◽  
Zhongyan Huang ◽  
Xiaosong Cao ◽  
...  
Keyword(s):  
Heavy Atom ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Heavy Atom Effect ◽  
Thermally Activated ◽  
Atom Effect

scholarly journals Heavy-Atom Effect Promotes Multi-Resonance Thermally Activated Delayed Fluorescence

2021 ◽  
Author(s):  
Tao Hua ◽  
Lisi Zhan ◽  
Nengquan Li ◽  
Zhongyan Huang ◽  
Xiaosong Cao ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Heavy Atom ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Heavy Atom Effect ◽  
Thermally Activated ◽  
Organic Light ◽  
Atom Effect

As one type of latest emitters with simultaneous high efficiency and color-purity, the development of multi-resonance thermally activated delayed fluorescence (MR-TADF) materials represents an important advancement for organic light-emitting diodes (OLEDs). We herein present a new strategy to improve the performance of MR-TADF emitters by fusing sulfur element into the B-N based framework, aiming to utilize the non-metal heavy-atom effect in accelerating the reverse intersystem crossing (RISC) process of the emitter. Two compounds, namely 2PTZBN and 2PXZBN, were developed in this work through rigidifying the DABNA-1 skeleton by sulfur or oxygen atoms. The theoretical calculations and photoluminescence studies revealed that the sulfur-incorporated 2PTZBN enabled considerable rate constant of RISC (<i>k</i><sub>RISC</sub>) up to 2.8 × 10<sup>5</sup> s<sup>-1</sup> in toluene due to larger spin-orbital coupling (SOC) values and smaller singlet-triplet energy splitting (Δ<i>E</i><sub>ST</sub>) compared with 2PXZBN. Consequently, organic light-emitting diodes based on 2PTZBN exhibited highly efficient green emission with maximum external quantum efficiency (EQE) of 25.5%.

scholarly journals Revealing Internal Heavy Chalcogen Atom Effect on the Photophysics of Dibenzo[a,j]phenazine-Cored Donor–Acceptor–Donor Triad

2021 ◽  
Author(s):  
Shimpei Goto ◽  
Yuya Nitta ◽  
Nicolas Decarli ◽  
Leonardo Evaristo de Sousa ◽  
Patrycja Stachelek ◽  
...  
Keyword(s):  
Room Temperature ◽  
Photophysical Properties ◽  
Heavy Atom ◽  
Delayed Fluorescence ◽  
Room Temperature Phosphorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor Acceptor ◽  
Mechanochromic Luminescence ◽  
Atom Effect

<div><div><div><p>A new twisted donor–acceptor–donor (D–A–D) multi-photofunctional organic molecule comprising of phenoselenazine as the electron-donors (Ds) and dibenzo[a,j]phenazine (DBPHZ) as the electron-acceptor (A) has been developed. The developed selenium-incorporated D–A–D compound is featured with multi-color polymorphism, distinct mechanochromic luminescence, chemically-stimulated luminochromism, thermally-activated delayed fluorescence, and room- temperature phosphorescence. The internal heavy atom effect on the photophysical properties of the D–A–D system has been investigated through the comparison with the physicochemical properties of a previously developed sulfur analogue and a tellurium analogue.</p></div></div></div>

scholarly journals Revealing Internal Heavy Chalcogen Atom Effect on the Photophysics of Dibenzo[a,j]phenazine-Cored Donor–Acceptor–Donor Triad

2021 ◽  
Author(s):  
Shimpei Goto ◽  
Yuya Nitta ◽  
Nicolas Decarli ◽  
Leonardo Evaristo de Sousa ◽  
Patrycja Stachelek ◽  
...  
Keyword(s):  
Room Temperature ◽  
Photophysical Properties ◽  
Heavy Atom ◽  
Delayed Fluorescence ◽  
Room Temperature Phosphorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor Acceptor ◽  
Mechanochromic Luminescence ◽  
Atom Effect

<div><div><div><p>A new twisted donor–acceptor–donor (D–A–D) multi-photofunctional organic molecule comprising of phenoselenazine as the electron-donors (Ds) and dibenzo[a,j]phenazine (DBPHZ) as the electron-acceptor (A) has been developed. The developed selenium-incorporated D–A–D compound is featured with multi-color polymorphism, distinct mechanochromic luminescence, chemically-stimulated luminochromism, thermally-activated delayed fluorescence, and room- temperature phosphorescence. The internal heavy atom effect on the photophysical properties of the D–A–D system has been investigated through the comparison with the physicochemical properties of a previously developed sulfur analogue and a tellurium analogue.</p></div></div></div>

Reducing lifetime in Cu(i) complexes with thermally activated delayed fluorescence and phosphorescence promoted by chalcogenolate–diimine ligands

2020 ◽  
Vol 8 (41) ◽  
pp. 14595-14604
Author(s):  
Giliandro Farias ◽  
Cristian A. M. Salla ◽  
Renata S. Heying ◽  
Adailton J. Bortoluzzi ◽  
Sergio F. Curcio ◽  
...  
Keyword(s):  
Heavy Atom ◽  
Delayed Fluorescence ◽  
Spin Orbit Coupling ◽  
Matrix Elements ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Diimine Ligands ◽  
Photoluminescence Lifetime ◽  
Atom Effect ◽  
Fluorescence And Phosphorescence

Cu(i) complexes without the expected heavy atom effect to enhance the spin–orbit coupling matrix elements, but with reduced photoluminescence lifetime.

Achieving high singlet-oxygen generation by applying the heavy-atom effect to thermally activated delayed fluorescent materials

2021 ◽  
Author(s):  
Ya-Fang Xiao ◽  
Jia-Xiong Chen ◽  
Wen-Cheng Chen ◽  
Xiuli Zheng ◽  
Chen Cao ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Heavy Atom ◽  
Synergetic Effect ◽  
Heavy Atom Effect ◽  
Oxygen Generation ◽  
Thermally Activated ◽  
Singlet Oxygen Generation ◽  
Fluorescent Materials ◽  
Atom Effect

Applying the heavy-atom effect to TADF photosensitizers achieves ultra-high 1O2 generation (ФΔ = 0.91) by the synergetic effect of small ΔEST and considerable SOC.

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