scholarly journals Research on Long-Lived Room-Temperature Phosphorescence of Carbazole-Naphthalimide Polylactides

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 790
Author(s):  
Zhiwei Li ◽  
Xingyuan Zhang
Keyword(s):  
Charge Transfer ◽  
Electrochemical Method ◽  
Room Temperature ◽  
Potential Candidate ◽  
Room Temperature Phosphorescence ◽  
Phosphorescence Lifetime ◽  
Donor Acceptor ◽  
Phosphorescence Emission ◽  
Carbazole Group

Two types of naphthalimide derivatives were synthesized by introducing a carbazole group and an n-butyl, respectively, into the naphthalimide system. The electron-donating ability of two kinds of derivatives was investigated by the electrochemical method. These two types of derivatives were used as initiators for the polymerization of d and l-lactide polymerization. Here, the emission and UV-vis absorption serve as the main focus. Compared with solely donor-initiated polylactide (PLA), the PLA with a donor-acceptor structure has a more efficient phosphorescence emission, of which the longest phosphorescence lifetime is up to 407 ms. The experimental results reveal the existence of charge-transfer states in the donor-acceptor-ended polymer. Due to the role of charge-transfer states, a red phosphorescent polymer was developed. Theoretically, these desirable advantages render synthesized PLAs a potential candidate for bioimaging and anti-counterfeiting.

scholarly journals Charge–Transfer Fluorescence and Room-Temperature Phosphorescence from a Bisamide-Based Derivative

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1370
Author(s):  
Chengjian Li ◽  
Chaozheng Zhuo ◽  
Jingwei Sun ◽  
Mi Ouyang
Keyword(s):  
Charge Transfer ◽  
Room Temperature ◽  
Luminescent Properties ◽  
Luminescent Materials ◽  
Room Temperature Phosphorescence ◽  
Single Crystal Structures ◽  
Singlet States ◽  
Donor And Acceptor ◽  
Donor Acceptor ◽  
The Relationship

The development of organic luminescent materials with bimodal emissions of both fluorescence and room-temperature phosphorescent (RTP) remains a challenge. The investigation of the relationship between fluorescence and RTP performance is especially rare. In this work, we obtained an organic luminescent molecule, 1,4-phenylenebis((9H-carbazol-9-yl)methanone) (PBCM), which exhibits bimodal emissions of cyan fluorescence and yellow RTP in its crystalline state through adopting an electron donor–acceptor–donor (D–A–D) structure. The charge–transfer (CT) effects in the bimodal luminescent properties of PBCM, as well as the single-crystal structures and thermal properties, were investigated. It was found that the CT effect in the singlet states effectively reduces the ∆Est and promotes the ISC processes, resulting in an efficient phosphorescence of PBCM at room temperature. In addition, many strong intermolecular interactions are formed between the donor and acceptor parts of adjacent molecules, leading to the rigid configurations and compact packing of molecules in crystals, which was also confirmed to facilitate the efficient bimodal emissions of PBCM.

Clustering-Triggered Efficient Room Temperature Phosphorescence from Nonconventional Luminophores

2019 ◽  
Author(s):  
Shuyuan Zheng ◽  
Taiping Hu ◽  
Xin Bin ◽  
Yunzhong Wang ◽  
Yuanping Yi ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Spin Orbit Coupling ◽  
Design Rationale ◽  
Emission Mechanism ◽  
Room Temperature Phosphorescence ◽  
Electronic Interactions ◽  
Energy Gaps ◽  
Theoretical Results

Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br>

Pure room temperature phosphorescence emission of organic host-guest doped system with quantum efficiency of 64%

2021 ◽  
Author(s):  
Xiaoqing Liu ◽  
Wenbo Dai ◽  
Qian Junjie ◽  
Yunxiang Lei ◽  
Miaochang Liu ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Room Temperature ◽  
Room Temperature Phosphorescence ◽  
Halogen Atoms ◽  
System P ◽  
Phosphorescence Emission

A new doped system with pure phosphorescent emission is constructed using four 1-(4-(diphenylamino)phenyl)-2-phenylethan-1-one derivatives containing halogen atoms as the guests and benzophenone as the host. That is, the doped system...

scholarly journals Regioisomeric Effect on the Excited-State Fate Leading to Room-Temperature Phosphorescence or Thermally Activated Delayed Fluorescence in a Dibenzophenazine-Cored Donor–Acceptor–Donor System

2021 ◽  
Author(s):  
Takumi Hosono ◽  
Nicolas Oliveira Decarli ◽  
Paola Zimmermann Crocomo ◽  
Tsuyoshi Goya ◽  
Leonardo Evaristo de Sousa ◽  
...  
Keyword(s):  
Excited State ◽  
Room Temperature ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Room Temperature Phosphorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Donor Acceptor ◽  
Emission Behavior

Exploring design principle for switching thermally activated dealyed fluorescecne (TADF) and room temperature phosphorescence (RTP) is a fundamentally imporant research in developing triplet-mediated photofunctional organic materials. Herein systematic studies on the regioisomeric and substituents effects in a twisted donor–acceptor–donor (D–A–D) scaffold (A = dibenzo[a,j]phenazine; D = dihydrophenazasiline) on the fate of the excited state have been performed. The study revealed that the regiosiomerism clearly affects the emission behavior of the D–A–D compounds. Distinct difference in TADF, dual TADF & RTP, and dual RTP were observed, depending on the host used. Furthermore, OLED organic light-emitting diodes (OLEDs) fabricated with the developed emitters achieved high external quantum yields for RTP-based OLEDS up to 7.4%.

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