TY  - JOUR
A1  - Holzer, Wolfgang
A1  - Penzkofer, Alfons
A1  - Schrader, Sigurd
A1  - Grimm, Bernhard
T1  - Photo-physical and lasing characterisation of a polyparaphenylenevinylene (PPV) neat film
N2  - The wave-guided travelling-wave laser action (amplified spontaneous emission) of a neat film of poly(p- phenylenevinylene) (PPV) on a quartz glass substrate prepared by a sulfinyl precursor technique is studied. The samples are transversally pumped with picosecond excitation pulses (wavelength 347.15 nm, duration 35 ps). Lasing occurs at 550 nm. The optical constants of the neat films are determined by transmittance measurements exploiting the multiple beam interference in the transparency region. A fluorescence spectroscopic characterisation is carried out determining the fluorescence quantum distribution, fluorescence quantum yield, degree of fluorescence polarisation, and fluorescence lifetime. The emitting chromophore size (emitting singlet exciton extension) is determined by the ratio of exciton radiative lifetime to repeat-unit based radiative lifetime. The obtained size of about two repeat units is discussed in a disordered solid-state polymer model
Y1  - 2005
SN  - 0306-8919
ER  - 
TY  - JOUR
A1  - Schrader, Sigurd
A1  - Penzkofer, Alfons
A1  - Holzer, W.
A1  - Velagapudi, Ramakrishna
A1  - Grimm, Bernhard
T1  - Laser spectroscopic investigation of a new precursor - type polyparaphenylenevinylene
N2  - Optical, structural and morphological properties of thin films of polyparaphenylenevinylene (PPV) formed by an alkyl sulfinyl precursor route have been studied. Thin films were fabricated on an optical glass and on quartz glass either by spin-coating of the precursor solution or by layer-by-layer deposition using Langmuir-Blodgett technique. PPV precursor films were also spin-coated on gold-coated glass in order to study thin-film optical parameters by surface plasmon spectroscopy. We have been successful in forming about 40 precursor mono layers on quartz glass by Langmuir- Blodgett technique using optimized surface pressure and dipping conditions. After thermal conversion of the precursor layers good quality fluorescent PPV films of yellow colour have been obtained. Optical characterization of the films was carried out by linear absorption and emission spectroscopy, ellipsometry, and surface plasmon spectroscopy. Structural and morphological studies on the thin films were carried out by using X-ray scattering and atomic force microscopy. Wave- guided travelling-wave laser action has been achieved in a PPV film on quartz glass. The sample was transversally pumped with picosecond laser pulses (wavelength 347.15 nm, duration 35 ps). Laser emission occurred at 550 nm for pump pulse energy densities above 1 x 10(-4) J cm(-2). (C) 2004 Elsevier B.V. All rights reserved
Y1  - 2004
SN  - 0022-2313
ER  -