Ab initio MO calculations of electronic coupling matrix elements on model systems for intramolecular electron transfer, hole transfer, and triplet energy transfer: distance dependence and pathway in electron transfer and relationship of triplet energy transfer with electron and hole transfer

1993 ◽  
Vol 97 (50) ◽  
pp. 13117-13125 ◽  
Author(s):  
Nobuaki Koga ◽  
Keiichiro Sameshima ◽  
Keiji Morokuma
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Model Systems ◽  
Electronic Coupling ◽  
Intramolecular Electron Transfer ◽  
Triplet Energy ◽  
Hole Transfer ◽  
Distance Dependence ◽  
Relationship Of ◽  
Triplet Energy Transfer

scholarly journals Shallow distance-dependent triplet energy migration mediated by endothermic charge-transfer

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Runchen Lai ◽  
Yangyi Liu ◽  
Xiao Luo ◽  
Lan Chen ◽  
Yaoyao Han ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
Semiconductor Nanocrystals ◽  
Electronic Coupling ◽  
Alternative Mechanism ◽  
Acceptor Pair ◽  
Triplet Energy ◽  
Distance Dependence ◽  
Donor Acceptor ◽  
Triplet Energy Transfer

AbstractConventional wisdom posits that spin-triplet energy transfer (TET) is only operative over short distances because Dexter-type electronic coupling for TET rapidly decreases with increasing donor acceptor separation. While coherent mechanisms such as super-exchange can enhance the magnitude of electronic coupling, they are equally attenuated with distance. Here, we report endothermic charge-transfer-mediated TET as an alternative mechanism featuring shallow distance-dependence and experimentally demonstrated it using a linked nanocrystal-polyacene donor acceptor pair. Donor-acceptor electronic coupling is quantitatively controlled through wavefunction leakage out of the core/shell semiconductor nanocrystals, while the charge/energy transfer driving force is conserved. Attenuation of the TET rate as a function of shell thickness clearly follows the trend of hole probability density on nanocrystal surfaces rather than the product of electron and hole densities, consistent with endothermic hole-transfer-mediated TET. The shallow distance-dependence afforded by this mechanism enables efficient TET across distances well beyond the nominal range of Dexter or super-exchange paradigms.

scholarly journals Mechanisms of triplet energy transfer across the inorganic nanocrystal/organic molecule interface

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiao Luo ◽  
Yaoyao Han ◽  
Zongwei Chen ◽  
Yulu Li ◽  
Guijie Liang ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
Organic Molecule ◽  
Transient Absorption ◽  
High Energy ◽  
Model Systems ◽  
Trap States ◽  
Triplet Energy ◽  
Surface Trap ◽  
Triplet Energy Transfer

AbstractThe mechanisms of triplet energy transfer across the inorganic nanocrystal/organic molecule interface remain poorly understood. Many seemingly contradictory results have been reported, mainly because of the complicated trap states characteristic of inorganic semiconductors and the ill-defined relative energetics between semiconductors and molecules used in these studies. Here we clarify the transfer mechanisms by performing combined transient absorption and photoluminescence measurements, both with sub-picosecond time resolution, on model systems comprising lead halide perovskite nanocrystals with very low surface trap densities as the triplet donor and polyacenes which either favour or prohibit charge transfer as the triplet acceptors. Hole transfer from nanocrystals to tetracene is energetically favoured, and hence triplet transfer proceeds via a charge separated state. In contrast, charge transfer to naphthalene is energetically unfavourable and spectroscopy shows direct triplet transfer from nanocrystals to naphthalene; nonetheless, this “direct” process could also be mediated by a high-energy, virtual charge-transfer state.

scholarly journals Sensitization of ultra-long-range excited-state electron transfer by energy transfer in a polymerized film

2012 ◽  
Vol 109 (38) ◽  
pp. 15132-15135 ◽  
Author(s):  
Akitaka Ito ◽  
David J. Stewart ◽  
Zhen Fang ◽  
M. Kyle Brennaman ◽  
Thomas J. Meyer
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Excited State ◽  
Charge Transfer ◽  
Long Range ◽  
Methyl Viologen ◽  
Polymer Network ◽  
Triplet Energy ◽  
Ligand Charge Transfer ◽  
Triplet Energy Transfer

Distance-dependent energy transfer occurs from the Metal-to-Ligand Charge Transfer (MLCT) excited state to an anthracene-acrylate derivative (Acr-An) incorporated into the polymer network of a semirigid poly(ethyleneglycol)dimethacrylate monolith. Following excitation, to Acr-An triplet energy transfer occurs followed by long-range, Acr-3An—Acr-An → Acr-An—Acr-3An, energy migration. With methyl viologen dication (MV2+) added as a trap, Acr-3An + MV2+ → Acr-An+ + MV+ electron transfer results in sensitized electron transfer quenching over a distance of approximately 90 Å.

An Unusually Shallow Distance-Dependence for Triplet-Energy Transfer

2000 ◽  
Vol 39 (23) ◽  
pp. 4287-4290 ◽  
Author(s):  
Anthony Harriman ◽  
Abderrahim Khatyr ◽  
Raymond Ziessel ◽  
Andrew C. Benniston
Keyword(s):  
Energy Transfer ◽  
Triplet Energy ◽  
Distance Dependence ◽  
Triplet Energy Transfer
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