Perturbations of the low-energy doublet excited state of chromium(III). Competing heavy-atom and macrocyclic ligand effects in thermally activated relaxation pathways

1989 ◽  
Vol 28 (13) ◽  
pp. 2574-2583 ◽  
Author(s):  
Ronald B. Lessard ◽  
John F. Endicott ◽  
Marc W. Perkovic ◽  
L. A. Ochrymowycz
Keyword(s):  
Excited State ◽  
Heavy Atom ◽  
Macrocyclic Ligand ◽  
Low Energy ◽  
Thermally Activated ◽  
Ligand Effects

Achieving high singlet-oxygen generation by applying the heavy-atom effect to thermally activated delayed fluorescent materials

2021 ◽  
Author(s):  
Ya-Fang Xiao ◽  
Jia-Xiong Chen ◽  
Wen-Cheng Chen ◽  
Xiuli Zheng ◽  
Chen Cao ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Heavy Atom ◽  
Synergetic Effect ◽  
Heavy Atom Effect ◽  
Oxygen Generation ◽  
Thermally Activated ◽  
Singlet Oxygen Generation ◽  
Fluorescent Materials ◽  
Atom Effect

Applying the heavy-atom effect to TADF photosensitizers achieves ultra-high 1O2 generation (ФΔ = 0.91) by the synergetic effect of small ΔEST and considerable SOC.

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%.

Thermally activated delayed fluorescence materials as organic photosensitizers

2021 ◽  
Vol 57 (82) ◽  
pp. 10675-10688
Author(s):  
Alexander M. Polgar ◽  
Zachary M. Hudson
Keyword(s):  
Excited State ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
State Behaviour

The use of thermally activated delayed fluorescence molecules as photosensitizers is covered with emphasis on strategies employed to control their excited state behaviour to suit a particular application.

Photoinduced ligand dissociation follows reverse energy gap law: nitrile photodissociation from low energy 3MLCT excited states

2020 ◽  
Vol 56 (29) ◽  
pp. 4070-4073
Author(s):  
Lauren M. Loftus ◽  
Jeffrey J. Rack ◽  
Claudia Turro
Keyword(s):  
Excited State ◽  
Excited States ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Energy Gap ◽  
Low Energy ◽  
Transient Absorption Spectroscopy ◽  
Ligand Dissociation ◽  
Energy Gap Law

Transient absorption spectroscopy is used to show that stabilization of the 3MLCT excited state in a series of Ru(ii) complexes leads to decreased population of the 3LF state, but does not reduce the efficiency of photoinduced nitrile dissociation.

scholarly journals Hinged and Wide: A New P^P Ligand for Emissive [Cu(P^P)(N^N)][PF6] Complexes

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3934 ◽  
Author(s):  
Sarah Keller ◽  
Matthias Bantle ◽  
Alessandro Prescimone ◽  
Edwin C. Constable ◽  
Catherine E. Housecroft
Keyword(s):  
Mass Spectrometry ◽  
Excited State ◽  
Quantum Yield ◽  
Delayed Fluorescence ◽  
Ionization Mass ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Single Crystal Structures ◽  
Photoluminescence Quantum Yield ◽  
Deaerated Solution

Heteroleptic [Cu(BIPHEP)(N^N)][PF6] complexes (BIPHEP = 1,1′-biphenyl-2,2′-diylbis(diphenylphosphane)), in which N^N is 2,2′-bipyridine (bpy), 6-methyl-2,2′-bipyridine (6-Mebpy), 6-ethyl-2,2′-bipyridine (6-Etbpy), or 5,5′-dimethyl-2,2′-bipyridine (5,5′-Me2bpy), have been synthesized and characterized using multinuclear NMR spectroscopies and electrospray ionization mass spectrometry. The single crystal structures of [Cu(BIPHEP)(bpy)][PF6]∙CH2Cl2, [Cu(BIPHEP)(5,5′-Me2bpy)][PF6]∙CH2Cl2, [Cu(BIPHEP)(6-Mebpy)][PF6]∙Et2O∙0.5H2O and [Cu(BIPHEP)(6-Etbpy)][PF6] confirm distorted tetrahedral {Cu(P^P)(N^N)} coordination environments. Each compound shows a quasi-reversible Cu+/Cu2+ process. In deaerated solution, the compounds are weak emitters. Powdered samples are yellow emitters (λemmax in the range 558–583 nm) and [Cu(BIPHEP)(5,5′-Me2bpy)][PF6] exhibits the highest photoluminescence quantum yield (PLQY = 14%). On cooling to 77 K (frozen 2-methyloxolane), the emission maxima are red-shifted and the excited state lifetimes increase from τ1/2 < 8 μs, to τ1/2 values of up to 53 μs, consistent with the compounds with N^N = 6-Mebpy, 6-Etbpy and 5,5′-Me2bpy exhibiting thermally activated delayed fluorescence (TADF).

Sign in / Sign up

Export Citation Format

Share Document