scholarly journals Quantum dynamics of ultrafast photoinduced processes in organic semiconductors: exciton dissociation at polymer heterojunctions

PAMM ◽  
2007 ◽  
Vol 7 (1) ◽  
pp. 1130601-1130602 ◽  
Author(s):  
Irene Burghardt ◽  
Eric R. Bittner ◽  
Hiroyuki Tamura
Keyword(s):  
Organic Semiconductors ◽  
Quantum Dynamics ◽  
Exciton Dissociation ◽  
Photoinduced Processes

scholarly journals Spontaneous exciton dissociation enables spin state interconversion in delayed fluorescence organic semiconductors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alexander J. Gillett ◽  
Claire Tonnelé ◽  
Giacomo Londi ◽  
Gaetano Ricci ◽  
Manon Catherin ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Energy Gap ◽  
Hyperfine Interactions ◽  
Delayed Fluorescence ◽  
Exciton Dissociation ◽  
Triplet Energy ◽  
Electron Hole ◽  
Singlet Exciton ◽  
Average Electron ◽  
Spin Orbit Interactions

AbstractEngineering a low singlet-triplet energy gap (ΔEST) is necessary for efficient reverse intersystem crossing (rISC) in delayed fluorescence (DF) organic semiconductors but results in a small radiative rate that limits performance in LEDs. Here, we study a model DF material, BF2, that exhibits a strong optical absorption (absorption coefficient = 3.8 × 105 cm−1) and a relatively large ΔEST of 0.2 eV. In isolated BF2 molecules, intramolecular rISC is slow (delayed lifetime = 260 μs), but in aggregated films, BF2 generates intermolecular charge transfer (inter-CT) states on picosecond timescales. In contrast to the microsecond intramolecular rISC that is promoted by spin-orbit interactions in most isolated DF molecules, photoluminescence-detected magnetic resonance shows that these inter-CT states undergo rISC mediated by hyperfine interactions on a ~24 ns timescale and have an average electron-hole separation of ≥1.5 nm. Transfer back to the emissive singlet exciton then enables efficient DF and LED operation. Thus, access to these inter-CT states, which is possible even at low BF2 doping concentrations of 4 wt%, resolves the conflicting requirements of fast radiative emission and low ΔEST in organic DF emitters.

Exciton dissociation and charge carrier recombination processes in organic semiconductors

2011 ◽  
Vol 135 (22) ◽  
pp. 224901 ◽  
Author(s):  
Luiz A. Ribeiro ◽  
Pedro H. Oliveira Neto ◽  
Wiliam F. da Cunha ◽  
Luiz F. Roncaratti ◽  
Ricardo Gargano ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Organic Semiconductors ◽  
Exciton Dissociation ◽  
Carrier Recombination ◽  
Recombination Processes ◽  
Charge Carrier Recombination

Quantum Dynamics of Ultrafast Photoinduced Processes in Biological Molecules

2007 ◽  
Author(s):  
Fabrizio Santoro ◽  
Vincenzo Barone ◽  
Roberto Improta ◽  
Alessandro Lami ◽  
Massimo Olivucci ◽  
...  
Keyword(s):  
Quantum Dynamics ◽  
Biological Molecules ◽  
Photoinduced Processes

Exciton Dissociation at Thiophene/Fullerene Interfaces: The Electronic Structures and Quantum Dynamics

2011 ◽  
Vol 115 (20) ◽  
pp. 10205-10210 ◽  
Author(s):  
Hiroyuki Tamura ◽  
Irene Burghardt ◽  
Masaru Tsukada
Keyword(s):  
Electronic Structures ◽  
Quantum Dynamics ◽  
Exciton Dissociation

Double-Excitation Dynamics in m-LPPP probed with sub-20 fs Time Resolution

2003 ◽  
Vol 771 ◽  
Author(s):  
C. Gadermaier ◽  
G. Cerullo ◽  
C. Manzoni ◽  
U. Scherf ◽  
E.J.W. List ◽  
...  
Keyword(s):  
Vibrational Relaxation ◽  
Broad Band ◽  
Generation Efficiency ◽  
Exciton Dissociation ◽  
Charge Generation ◽  
Carrier Generation ◽  
Dissociation Probability ◽  
Ultrafast Relaxation ◽  
First Excited State ◽  
Differential Transmission

AbstractIn a novel modification of transient differential transmission spectroscopy, the first excited state S1 is reexcited via a second laser pulse towards a higher lying state Sn. The dynamics of the relaxation of this state Sn as well as the states created from Sn are revealed by a broad-band probe pulse.We find that the charge carrier generation efficiency from Sn is higher compared to S1. The push and probe durations below 20 fs enable the temporal resolution of the ultrafast relaxation of the Sn state and enables us to identify the two main contributions to enhanced charge generation from Sn, energy migration towards sites of high dissociation probability, and exciton dissociation during vibrational relaxation.

THE NOTHING THAT REALLY IS!

2016 ◽  
Vol 12 (1) ◽  
pp. 4172-4177
Author(s):  
Abdul Malek
Keyword(s):  
Quantum Dynamics ◽  
Theoretical Physics ◽  
Historical Evolution ◽  
Proper Understanding ◽  
Physical Universe ◽  
Wave Particle Duality ◽  
Negative Effect ◽  
Materialist Interpretation

The denial of the existence of contradiction is at the root of all idealism in epistemology and the cause for alienations.  This alienation has become a hindrance for the understanding of the nature and the historical evolution mathematics itself and its role as an instrument in the enquiry of the physical universe (1). A dialectical materialist approach incorporating  the role of the contradiction of the unity of the opposites, chance and necessity etc., can provide a proper understanding of the historical evolution of mathematics and  may ameliorate  the negative effect of the alienation in modern theoretical physics and cosmology. The dialectical view also offers a more plausible materialist interpretation of the bewildering wave-particle duality in quantum dynamics (2).

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