scholarly journals Ultralong UV/mechano-excited room temperature phosphorescence from purely organic cluster excitons

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Xuepeng Zhang ◽  
Lili Du ◽  
Weijun Zhao ◽  
Zheng Zhao ◽  
Yu Xiong ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Transient Absorption ◽  
Transient State ◽  
Exciton Model ◽  
Room Temperature Phosphorescence ◽  
Naphthalic Anhydride ◽  
Femtosecond Transient Absorption ◽  
Organic Solid ◽  
Absorption Studies

AbstractPurely organic room temperature phosphorescence (RTP) has attracted wide attention recently due to its various application potentials. However, ultralong RTP (URTP) with high efficiency is still rarely achieved. Herein, by dissolving 1,8-naphthalic anhydride in certain organic solid hosts, URTP with a lifetime of over 600 ms and overall quantum yield of over 20% is realized. Meanwhile, the URTP can also be achieved by mechanical excitation when the host is mechanoluminescent. Femtosecond transient absorption studies reveal that intersystem crossing of the host is accelerated substantially in the presence of a trace amount of 1,8-naphthalic anhydride. Accordingly, we propose that a cluster exciton spanning the host and guest forms as a transient state before the guest acts as an energy trap for the RTP state. The cluster exciton model proposed here is expected to help expand the varieties of purely organic URTP materials based on an advanced understanding of guest/host combinations.

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>

scholarly journals Femtosecond Transient Absorption Studies of Two Novel Energetic Tetrazole Derivatives

2021 ◽  
pp. 100016
Author(s):  
Naga Krishnakanth Katturi ◽  
Chinmoy Biswas ◽  
Nagarjuna Kommu ◽  
Sai Santosh Kumar Raavi ◽  
Venugopal Rao Soma
Keyword(s):  
Transient Absorption ◽  
Femtosecond Transient Absorption ◽  
Absorption Studies ◽  
Tetrazole Derivatives

Covalent decoration onto the outer walls of double walled carbon nanotubes with perylenediimides

2015 ◽  
Vol 3 (19) ◽  
pp. 4960-4969 ◽  
Author(s):  
Myriam Barrejón ◽  
Sara Pla ◽  
Isadora Berlanga ◽  
María J. Gómez-Escalonilla ◽  
Luis Martín-Gomis ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Charge Separation ◽  
Transient Absorption ◽  
Femtosecond Transient Absorption ◽  
Covalently Bonded ◽  
Absorption Studies ◽  
Double Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Three new covalently bonded DWCNT–PDIs have been synthesized and characterized, showing exclusively functionalization of the outer walls leaving the inner walls intact. Femtosecond transient absorption studies were performed to seek evidence of charge separation in these hybrids.

Femtosecond Transient Absorption Studies of Energy Transfer within Chromophore-Labeled Dendrimers

2001 ◽  
Vol 105 (7) ◽  
pp. 1307-1312 ◽  
Author(s):  
Frederik V. R. Neuwahl ◽  
Roberto Righini ◽  
Alex Adronov ◽  
Patrick R. L. Malenfant ◽  
Jean M. J. Fréchet
Keyword(s):  
Energy Transfer ◽  
Transient Absorption ◽  
Femtosecond Transient Absorption ◽  
Absorption Studies

Femtosecond transient absorption studies of electrons in liquid alkanes

1995 ◽  
Vol 99 (19) ◽  
pp. 7436-7438 ◽  
Author(s):  
Frederick H. Long ◽  
Hong Lu ◽  
Kenneth B. Eisenthal
Keyword(s):  
Transient Absorption ◽  
Femtosecond Transient Absorption ◽  
Absorption Studies ◽  
Liquid Alkanes

scholarly journals Critical Role of H-Aggregation for High-Efficiency Photoinduced Charge Generation in Pristine Pentamethine Cyanine Salts

2021 ◽  
Author(s):  
George Cameron Fish ◽  
Juan Manuel Moreno-Naranjo ◽  
Andreas Billion ◽  
Daniel Kratzert ◽  
Erwin Hack ◽  
...  
Keyword(s):  
High Efficiency ◽  
Transient Absorption ◽  
Critical Role ◽  
Optoelectronic Devices ◽  
Transient Absorption Spectroscopy ◽  
Organic Photovoltaic ◽  
Charge Generation ◽  
Femtosecond Transient Absorption ◽  
Photoinduced Charge

The mechanism of photoinduced symmetry-breaking charge separation in solid cyanine salts at the base of organic photovoltaic and optoelectronic devices is still debated. Here, we employ femtosecond transient absorption spectroscopy...

Excited state electron transfer in A2 and A2B2 functionalized zinc porphyrins carrying rigid and flexible β-pyrrole π-extended substituents

2020 ◽  
Vol 24 (05n07) ◽  
pp. 904-919
Author(s):  
Michael B. Thomas ◽  
Siddhartha Kumar ◽  
Timothy Esquivel ◽  
Hong Wang ◽  
Francis D’Souza
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Transient Absorption ◽  
Binding Constants ◽  
Free Energy Calculations ◽  
Stable Complex ◽  
State Electron ◽  
Femtosecond Transient Absorption ◽  
Absorption Studies ◽  
Zinc Porphyrins

Optical absorption and emission, electrochemical, and photochemical properties of peripherally functionalized with flexible and rigid [Formula: see text]-extended substituents on A2 and A2B2 type zinc porphyrins is investigated. The significance of rigid [Formula: see text]-substituents over flexible ones in governing the spectral properties is unraveled. Flexible [Formula: see text]-substituents on the porphyrin ring caused appreciable spectral broadening compared to porphyrin carrying rigid [Formula: see text]-substituents. Further, supramolecular dyads are formed by coordinating phenyl imidazole functionalized fullerene, C[Formula: see text]Im. The calculated binding constants for the 1:1 complexes is in the order of 2–7 × 105 M[Formula: see text] suggesting stable complex formation. Free-energy calculations performed according to the Rehm–Weller approach suggested possibility of excited state electron transfer in these dyads. Femtosecond transient absorption studies of the dyads performed in [Formula: see text]-dichlorobenzene showed evidence of occurrence of electron transfer from the singlet-excited state that was in competition with the intersystem crossing process to populate the triplet-excited state of porphyrins.

A high efficiency pure organic room temperature phosphorescence polymer PPV derivative for OLED

2019 ◽  
Vol 64 ◽  
pp. 247-251 ◽  
Author(s):  
Ying He ◽  
Nianhe Cheng ◽  
Xin Xu ◽  
Jiawei Fu ◽  
Jun-an Wang
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Room Temperature Phosphorescence
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