Matrix-assisted pulsed laser evaporation of polyfluorene thin films

Vibrational spectroscopy study on α and β phases in iridium‐complex‐containing polyfluorenes

“…These absorption peaks are close to FTIR peaks due to PFO which appear at 2953, 2926, and 2855 cm -1 , and the whole spectrum is quite similar to the previously reported PFO spectrum [5,6]. The 2855 and 2926 cm -1 peaks have been attributed to C-H stretching vibrations of alkyl chain, while 2953 cm -1 peak to C-H stretching mode of aromatic ring [5,6]. Absorption due to Ir(thq) 2 (dbm) monomer was not observed at 2000-8000 cm -1 .…”

“…Their peaks are located at 2953, 2924, and 2853 cm -1 , with a shoulder at about 2900 cm -1 for all the films except PFO-Ir16 where the 2924 and 2853 cm -1 peaks shift to 2918 and 2849 cm -1 , respectively. These absorption peaks are close to FTIR peaks due to PFO which appear at 2953, 2926, and 2855 cm -1 , and the whole spectrum is quite similar to the previously reported PFO spectrum [5,6]. The 2855 and 2926 cm -1 peaks have been attributed to C-H stretching vibrations of alkyl chain, while 2953 cm -1 peak to C-H stretching mode of aromatic ring [5,6].…”

Electric-field effects on photoinduced dynamics and function

“…4. The PL spectra, which were independent of the excitation wavelength, are assigned to the fluorescence emitted from β-phase of PFO [28]. With excitation at a longer wavelength of 344 nm, the E-PL spectra observed with a field strength of 0.4 MV cm -1 shows the same shape as the one of the first derivative of the PL spectrum, indicating the Stark shift resulting from the difference in molecular polarizability between the emitting state and the ground state.…”

Light scattering studies of organic field effect transistors

“…In general, it is often not possible to deposit such films via spincoating as the dielectric may be susceptible to solvent induced damage. The MAPLE technique has been used to deposit polyfluorene-based,49,50 as well as P3HT51 polymer films. The optical and structural properties are similar to that of spin-coated films.In this work, OFETs were fabricated using a fluorene co-polymer (9,9dioctylfloureneco-bis-N,N-(4-butylphenyl)-bis-N,N-phenyl-1,4phenylenediamine) (PFB), thin film grown both by MAPLE and standard spin-coating techniques.…”

“…Since the maximum absorbance of PFB occurs at ~350 nm,49 energy imparted from the laser is expected to be absorbed by the solvent, and not by the PFB. Furthermore, for polyflourenes films, toluene has been shown to give better films than other Chlorine-bearing solvents 50. The laser (Physik COMPex, pulse duration of 20 ns), at a pulse rate with an energy density of 0.9mJ/cm 2 , was directed at an angle of incidence of 45 o at the cold target, which had been placed in an evacuated chamber.…”