Phonons spreading from laser-heated gold nanoparticle array accelerate diffusion of excitons in an underlying polythiophene thin film

0474036 - ÚMCH 2018 RIV GB eng J - Journal Article
Rais, David - Menšík, Miroslav - Paruzel, Bartosz - Kurunthu, Dharmalingam - Pfleger, Jiří
Phonons spreading from laser-heated gold nanoparticle array accelerate diffusion of excitons in an underlying polythiophene thin film.
Physical Chemistry Chemical Physics. Roč. 19, č. 16 (2017), s. 10562-10570. ISSN 1463-9076. E-ISSN 1463-9084
R&D Projects: GA MŠMT(CZ) LO1507; GA MŠMT(CZ) LD14011; GA ČR(CZ) GA15-05095S
Grant - others:European Commission(XE) COST Action MP1202 HINT
Institutional support: RVO:61389013
Keywords : P3HT * plasmon * laser-induced heating
OECD category: Polymer science
Impact factor: 3.906, year: 2017

Localized surface plasmon (LSP) photophysical phenomena occurring in metal nanostructures are often presented as a method to effectively couple light into photovoltaic devices of sub-wavelength-scale thickness. However, the excitation of LSP is also associated with rapid energy dissipation leading to local heating, which affects the excitation energy pathway. We studied a system consisting of a planar gold nanoparticle (AuNP) array deposited at the surface of a semiconducting polymer thin film (P3HT). We observed heat transfer from laser pulse excited AuNPs into the P3HT, which was evidenced as a long-living thermochromic effect on transient optical absorption. By modeling of the ultrafast kinetics of exciton population evolution, we determined that their decay was caused by their mutual annihilation. The decay rate was controlled by a phonon-assisted one-dimensional diffusion mechanism with a diffusion constant of 2.2 nm2 ps-1. The transferred heat resulted in an increase of the diffusion constant by a factor of almost 2, compared to the control system of P3HT without AuNPs. These results are of practical use for the design of plasmon-enhanced optoelectronic devices.
Permanent Link: http://hdl.handle.net/11104/0271661