Details

Autor(en) / Beteiligte

• Knyazev, Mikhail
• Karimullin, Kamil
• Naumov, Andrei

Titel

Revisiting the combined photon echo and single‐molecule studies of low‐temperature dynamics in a dye‐doped polymer

Ist Teil von

• Physica status solidi. PSS-RRL. Rapid research letters, 2017-03, Vol.11 (3), p.1600414-n/a

Ort / Verlag

Berlin: WILEY‐VCH Verlag Berlin GmbH

Erscheinungsjahr

2017

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• The photon echo (PE) spectroscopy and single‐molecule spectroscopy (SMS) may be combined to give a very powerful tool for comprehensive study of low‐temperature dynamics in dye‐doped disordered solids (polymers, glasses). At the same time, this type of studies are likely to reveal discrepancies when comparing characteristic times of optical dephasing T2 and single‐molecule zero‐phonon spectral lines (ZPL) broadening obtained from PE and SMS, correspondingly, for tetra‐tert‐butylterrylene in polyisobutylene in the temperature range of a few–dozen of Kelvins [see Phys. Status Solidi B 241, 3480 and 3487 (2004)]. Inexplicably, PE‐experiments demonstrated T2‐times to be much shorter than it is sufficient to cause the corresponding ZPL broadening. Here we experimentally solve this problem and show that at T = 4.5–15 K the incoherent PE gives T2‐times which correspond to the narrowest SM ZPL. On the SM‐level there is a pronounced additional ZPL‐broadening due to spectral diffusion processes which are strongly dependent on the characteristics time of the measurement (tens of nanoseconds for PE and seconds for SMS). There is also a broad distribution of ZPL spectral widths for different SMs due to different local environments, that contribute differently to both the optical dephasing and the spectral diffusion processes, but always in addition to the value of inverse optical dephasing times measured using a PE technique. The tunneling and vibrational relaxation processes in doped polymer (polyisobutylene) film has been reinvestigated using incoherent photon echo (IPE) and compared with single‐molecule spectroscopy (SMS) data. It has been shown that at T = 4.5–15 K the IPE gives optical dephasing times which correspond to the narrowest electronic spectra of single dye molecules. From this analysis we can conclude that the former contradiction between PE and SMS data has been resolved.