scholarly journals Theoretical investigation of the effects of various substituents on the large energy gap between triplet excited-states of anthracene

RSC Advances ◽  
2018 ◽  
Vol 8 (49) ◽  
pp. 27979-27987 ◽  
Author(s):  
Yu Dawei ◽  
Zhang Xiaojuan ◽  
Wang Zhiming ◽  
Yang Bing ◽  
Ma Yuguang ◽  
...  
Keyword(s):  
Excited States ◽  
Theoretical Investigation ◽  
Energy Gap ◽  
Large Energy ◽  
Organic Electroluminescent ◽  
Triplet Excited States

The utilization of excitons is key to the effectiveness of organic electroluminescent materials.

scholarly journals Computational investigation on the large energy gap between the triplet excited-states in acenes

RSC Advances ◽  
2017 ◽  
Vol 7 (43) ◽  
pp. 26697-26703 ◽  
Author(s):  
Y. Y. Pan ◽  
J. Huang ◽  
Z. M. Wang ◽  
D. W. Yu ◽  
B. Yang ◽  
...  
Keyword(s):  
Excited State ◽  
Excited States ◽  
Organic Materials ◽  
Energy Gap ◽  
Great Influence ◽  
Accurate Description ◽  
Large Energy ◽  
Computational Investigation ◽  
State Behavior ◽  
Triplet Excited States

Accurate description triplet excited states is a challenge of organic materials. In this work, we investigate excited state behavior of acenes. The results show that the symmetry of the transition orbital have a great influence on the energy gap.

scholarly journals Delayed Fluorescence from Inverted Singlet and Triplet Excited States for Efficient Organic Light-Emitting Diodes

2021 ◽  
Author(s):  
Daigo Miyajima ◽  
Naoya Aizawa ◽  
Yong-Jin Pu ◽  
Atsuko Nihonyanagi ◽  
Ryotaro Ibuka ◽  
...  
Keyword(s):  
Excited States ◽  
Light Emitting Diodes ◽  
Energy Gap ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Positive Energy ◽  
Light Emitting ◽  
Organic Light ◽  
Spin Singlet ◽  
Triplet Excited States

Abstract Hund’s multiplicity rule states that for a given electronic configuration, a higher spin state has a lower energy. Rephrasing this rule for molecular excited states predicts a positive energy gap between spin-singlet and spin-triplet excited states, which has been consistent with numerous experimental observations over almost a century. Here, we report a fluorescent molecule that disobeys Hund’s rule, possessing a negative singlet–triplet energy gap of –11 meV. The energy inversion of the singlet and triplet excited states results in delayed fluorescence with short time constants of 0.2 μs, which anomalously decrease with decreasing temperature due to the emissive singlet character of the lowest-energy excited state. Organic light-emitting diodes using this molecule exhibited a fast transient electroluminescence decay with a peak external quantum efficiency of 17%, demonstrating potential implications for optoelectronic devices, including displays, lighting, and lasers.

scholarly journals Tuning the singlet-triplet energy gap: a unique approach to efficient photosensitizers with aggregation-induced emission (AIE) characteristics

2015 ◽  
Vol 6 (10) ◽  
pp. 5824-5830 ◽  
Author(s):  
Shidang Xu ◽  
Youyong Yuan ◽  
Xiaolei Cai ◽  
Chong-Jing Zhang ◽  
Fang Hu ◽  
...  
Keyword(s):  
Excited State ◽  
Excited States ◽  
Energy Gap ◽  
Intersystem Crossing ◽  
Triplet Excited State ◽  
Triplet Energy ◽  
Aggregation Induced Emission ◽  
Unique Approach ◽  
Triplet Excited States

The efficiency of the intersystem crossing process can be improved by reducing the energy gap between the singlet and triplet excited states (ΔEST), which offers the opportunity to improve the yield of the triplet excited state.

Unconventional singlet fission materials

2021 ◽  
Author(s):  
Tobias Ullrich ◽  
Dominik Munz ◽  
Dirk M. Guldi
Keyword(s):  
Excited States ◽  
Singlet Fission ◽  
Triplet Excited States

Singlet fission (SF) is a photophysical downconversion pathway, in which a singlet excitation transforms into two triplet excited states.

Zur Berechnung der chemischen Verschiebung unter besonderer Berücksichtigung des paramagnetischen Terms / Attempts to the Calculation of the Chemical Shift with Especial Consideration of the Paramagnetic Term

1977 ◽  
Vol 32 (12) ◽  
pp. 1541-1543
Author(s):  
H. Sterk ◽  
J. J. Suschnigg
Keyword(s):  
Chemical Shift ◽  
Excited States ◽  
Ground State ◽  
Energy Gap

Abstract Attempts to the Calculation of the Chemical Shift with Especial Consideration of the Paramagnetic Term The calculation of the paramagnetic term according to the Pople formalism of the chemical shift is expanded. The hitherto constant value of the energy gap between the ground state and the excited states is replaced by the value of the lowest lying excitation. This leads to a remarkably better differentiation of the paramagnetic terms of different compounds. The influence is shown on ethane, ethene and ethine.

Different Quenching Effect of Intramolecular Rotation on the Singlet and Triplet Excited States of Bodipy

2017 ◽  
Vol 122 (1) ◽  
pp. 185-193 ◽  
Author(s):  
Zhangrong Lou ◽  
Yuqi Hou ◽  
Kepeng Chen ◽  
Jianzhang Zhao ◽  
Shaomin Ji ◽  
...  
Keyword(s):  
Excited States ◽  
Quenching Effect ◽  
Triplet Excited States ◽  
Intramolecular Rotation
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