Concept of the time-dependent diffusion coefficient of polarons in organic semiconductors and its determination from time-resolved spectroscopy
Identifikátory výsledku
Kód výsledku v IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389013%3A_____%2F18%3A00494710" target="_blank" >RIV/61389013:_____/18:00494710 - isvavai.cz</a>
Výsledek na webu
<a href="http://dx.doi.org/10.1021/acs.jpcc.8b07395" target="_blank" >http://dx.doi.org/10.1021/acs.jpcc.8b07395</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1021/acs.jpcc.8b07395" target="_blank" >10.1021/acs.jpcc.8b07395</a>
Alternativní jazyky
Jazyk výsledku
angličtina
Název v původním jazyce
Concept of the time-dependent diffusion coefficient of polarons in organic semiconductors and its determination from time-resolved spectroscopy
Popis výsledku v původním jazyce
The population of photogenerated species in organic semiconductors may decay due to their mutual annihilation upon collisions during their diffusive motion. The standard kinetic models for the population decay, n(t), assume a time-invariant diffusion coefficient, i.e., D(t) ≡ constant. This leads to a failure in predicting the experimentally observed temporal evolution of photogenerated species if it asymptotically approaches a power-law decay n(t) ∼ t–x, with x < 0.5. We have used a concept of the time-dependent diffusion coefficient and developed a novel mathematical method of its determination from decay collision rates obtained by transient optical absorption spectroscopy. We tested the applicability of this method on the interpretation of data of the decay of polaron population obtained experimentally by time-resolved transient absorption measurements on thin films of regioregular poly(3-hexylthiophene), where we recently reported a power-law asymptote with x = 0.24. While we do not assume any microscopic origin of the time variance of D(t), we argue that, as the charge-carrier trapping states occupancy drops with decaying charge concentration, the carrier motion slows down. This argument is supported by a recent report on a molecular-scale model taking into account significant local anisotropy present in linear conjugated polymers. Our concept can be applied for the description of the evolution of species, like polarons or excitons, in various organic materials, provided their decay kinetics is controlled by a mutual annihilation during one- or three-dimensional diffusion.
Název v anglickém jazyce
Concept of the time-dependent diffusion coefficient of polarons in organic semiconductors and its determination from time-resolved spectroscopy
Popis výsledku anglicky
The population of photogenerated species in organic semiconductors may decay due to their mutual annihilation upon collisions during their diffusive motion. The standard kinetic models for the population decay, n(t), assume a time-invariant diffusion coefficient, i.e., D(t) ≡ constant. This leads to a failure in predicting the experimentally observed temporal evolution of photogenerated species if it asymptotically approaches a power-law decay n(t) ∼ t–x, with x < 0.5. We have used a concept of the time-dependent diffusion coefficient and developed a novel mathematical method of its determination from decay collision rates obtained by transient optical absorption spectroscopy. We tested the applicability of this method on the interpretation of data of the decay of polaron population obtained experimentally by time-resolved transient absorption measurements on thin films of regioregular poly(3-hexylthiophene), where we recently reported a power-law asymptote with x = 0.24. While we do not assume any microscopic origin of the time variance of D(t), we argue that, as the charge-carrier trapping states occupancy drops with decaying charge concentration, the carrier motion slows down. This argument is supported by a recent report on a molecular-scale model taking into account significant local anisotropy present in linear conjugated polymers. Our concept can be applied for the description of the evolution of species, like polarons or excitons, in various organic materials, provided their decay kinetics is controlled by a mutual annihilation during one- or three-dimensional diffusion.
Klasifikace
Druh
J<sub>imp</sub> - Článek v periodiku v databázi Web of Science
CEP obor
—
OECD FORD obor
10404 - Polymer science
Návaznosti výsledku
Projekt
Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.
Návaznosti
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Ostatní
Rok uplatnění
2018
Kód důvěrnosti údajů
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Údaje specifické pro druh výsledku
Název periodika
Journal of Physical Chemistry C
ISSN
1932-7447
e-ISSN
—
Svazek periodika
122
Číslo periodika v rámci svazku
40
Stát vydavatele periodika
US - Spojené státy americké
Počet stran výsledku
8
Strana od-do
22876-22883
Kód UT WoS článku
000447471700008
EID výsledku v databázi Scopus
2-s2.0-85054401200