On the nonradiative and radiative decay rates and a modified exponential energy gap law for 4f–4f transitions in rare‐earth ions

1983 ◽  
Vol 78 (9) ◽  
pp. 5317-5323 ◽  
Author(s):  
J. M. F. van Dijk ◽  
M. F. H. Schuurmans
Keyword(s):  
Rare Earth ◽  
Radiative Decay ◽  
Energy Gap ◽  
Decay Rates ◽  
Rare Earth Ions ◽  
Energy Gap Law

scholarly journals Multiple Resonance Deep-red Emitters with Hybridized π-bonding/ non-bonding Orbitals to Surpass the Energy Gap Law

2021 ◽  
Author(s):  
Yuewei Zhang ◽  
Dongdong Zhang ◽  
Tianyu Huang ◽  
Alexander Gillett ◽  
Yang Liu ◽  
...  
Keyword(s):  
Radiative Decay ◽  
Near Infrared ◽  
Energy Gap ◽  
Light Emitting Diode ◽  
Resonance Effect ◽  
Infrared Region ◽  
Decay Rates ◽  
Quantum Yields ◽  
Multiple Resonance ◽  
Energy Gap Law

Abstract Efficient organic emitters in the deep-red to near infrared region are rare due to the ‘energy gap law’. Here, multiple boron (B)- and nitrogen (N)-atoms embedded polycyclic heteroaromatics featuring hybridized π-bonding/ non-bonding molecular orbitals are constructed, providing a way to overcome the above luminescent boundary. The introduction of B-phenyl-B and N-phenyl-N structures enhances the electronic coupling of those para-positioned atoms, forming restricted π-bonds on the phenyl-core for delocalized excited states and thus a narrow energy gap. The mutually ortho-positioned B- and N-atoms also induce a multiple resonance effect on the peripheral skeleton for the non-bonding orbitals, creating shallow potential energy surfaces to eliminate the high-frequency vibrational quenching. The corresponding deep-red emitters with peaks at 662 nm and 692 nm exhibit narrow full-width at half-maximums of 38 nm, high radiative decay rates of ~108 s-1, ~100% photo-luminance quantum yields and record-high maximum external quantum efficiencies of >28% in a normal planar organic light-emitting diode structure, simultaneously.

scholarly journals Overcome the Energy Gap Law in Near-Infrared Emissive Aggregates via Nonadiabatic Coupling Suppression

2021 ◽  
Author(s):  
Jie Xue ◽  
Jingyi Xu ◽  
Jiajun Ren ◽  
Qingxin Liang ◽  
Qi Ou ◽  
...  
Keyword(s):  
Radiative Decay ◽  
Near Infrared ◽  
High Efficiency ◽  
Organic Materials ◽  
Energy Gap ◽  
Delayed Fluorescence ◽  
Decay Rates ◽  
Nonadiabatic Coupling ◽  
Innovative Strategy ◽  
Energy Gap Law

<p>The pursuing of purely organic materials with high-efficiency near-infrared (NIR) emissions is fundamentally limited by the large non-radiative decay rates (<i>k</i><sub>nr</sub>) governed by the energy gap law. Here, we demonstrated a feasible and innovative strategy by employing intermolecular charge-transfer (CT) aggregates (CTA) to realize high-efficiency NIR emissions via nonadiabatic coupling suppression. The formation of CTA engenders intermolecular CT in the excited states; thereby, not only reducing the electronic nonadiabatic coupling and contributing to small <i>k</i><sub>nr</sub> for high-efficiency NIR photoluminescence, but also stabilizing excited-state energies and achieving thermally activated delayed fluorescence for high-efficiency NIR electroluminescence. This work provides new insights into aggregates and opens a new avenue for organic materials to overcome the energy gap law and achieve high-efficiency NIR emissions.<br></p>

scholarly journals Overcome the Energy Gap Law in Near-Infrared Emissive Aggregates via Nonadiabatic Coupling Suppression

2021 ◽  
Author(s):  
Jie Xue ◽  
Jingyi Xu ◽  
Jiajun Ren ◽  
Qingxin Liang ◽  
Qi Ou ◽  
...  
Keyword(s):  
Radiative Decay ◽  
Near Infrared ◽  
High Efficiency ◽  
Organic Materials ◽  
Energy Gap ◽  
Delayed Fluorescence ◽  
Decay Rates ◽  
Nonadiabatic Coupling ◽  
Innovative Strategy ◽  
Energy Gap Law

<p>The pursuing of purely organic materials with high-efficiency near-infrared (NIR) emissions is fundamentally limited by the large non-radiative decay rates (<i>k</i><sub>nr</sub>) governed by the energy gap law. Here, we demonstrated a feasible and innovative strategy by employing intermolecular charge-transfer (CT) aggregates (CTA) to realize high-efficiency NIR emissions via nonadiabatic coupling suppression. The formation of CTA engenders intermolecular CT in the excited states; thereby, not only reducing the electronic nonadiabatic coupling and contributing to small <i>k</i><sub>nr</sub> for high-efficiency NIR photoluminescence, but also stabilizing excited-state energies and achieving thermally activated delayed fluorescence for high-efficiency NIR electroluminescence. This work provides new insights into aggregates and opens a new avenue for organic materials to overcome the energy gap law and achieve high-efficiency NIR emissions.<br></p>

scholarly journals Inverted energy gap law for the nonradiative decay in fluorescent floppy molecules: larger fluorescence quantum yields for smaller energy gaps

2019 ◽  
Vol 6 (12) ◽  
pp. 1948-1954 ◽  
Author(s):  
Junqing Shi ◽  
Maria A. Izquierdo ◽  
Sangyoon Oh ◽  
Soo Young Park ◽  
Begoña Milián-Medina ◽  
...  
Keyword(s):  
Radiative Decay ◽  
Energy Gap ◽  
Quantum Yields ◽  
Nonradiative Decay ◽  
Fluorescence Quantum Yields ◽  
Energy Gaps ◽  
Energy Gap Law ◽  
Solution Increase ◽  
Floppy Molecules ◽  
Franck Condon

The non-radiative decay of substituted dicyano-distyrylbenzenes in solution increase with the Franck–Condon energy, being opposite to the conventional energy gap law.

Theoretical study of the substituent effect controlling the radiative and non-radiative decay processes of platinum(ii) complexes

2017 ◽  
Vol 19 (34) ◽  
pp. 23532-23540 ◽  
Author(s):  
Wei Shen ◽  
Wenting Zhang ◽  
Chaoyuan Zhu
Keyword(s):  
Substituent Effect ◽  
Radiative Decay ◽  
Theoretical Study ◽  
Energy Gap ◽  
Organometallic Complexes ◽  
Relaxation Dynamics ◽  
Energy Gap Law ◽  
Triplet Triplet Annihilation

By taking into account the energy gap law, relaxation dynamics and triplet–triplet annihilation (TTA), six organometallic complexes are systematically investigated for possible non-radiative decay processes.

The energy gap law for non-radiative decay in large molecules

1970 ◽  
Vol 1-2 ◽  
pp. 134-142 ◽  
Author(s):  
Robert Englman ◽  
Joshua Jortner
Keyword(s):  
Radiative Decay ◽  
Energy Gap ◽  
Large Molecules ◽  
Energy Gap Law
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