When equipped with double monochromators
, hybrid detectors, versatile TCSPC cards, and pulsed lasers capable of working in burst mode, the set-up offers a combined solution covering most demands of either high time, spectral, or spatial resolution in fields such as biology, physics, material or environmental sciences.
In accustomed fluorescence, an emission spectrum is attained by scanning the monochromator
of emission at various wavelengths ([[lambda].sub.em] ), at an appropriate excitation wavelength ([[lambda].sub.ex]), but in synchronous fluorescence scans both monochromators
detection system, whereas monochromators
refer only to the dispersing
Commercially available monochromators
use xenon or tungsten lamp sources requiring expensive filters to maintain a constant light intensity as the wavelength of light is changed to satisfy the experimental conditions.
Front-face reflection geometry was used with the help of a specially designed sample holder for holding the film specimens on a Hitachi F-4500 fluorescence spectrometer with a bandpass of 5 nm in the emission and excitation monochromators
. Finally, the corrected fluorescence spectra [I.sub.f] ([lambda]) were normalized with respect to absorbance at [[lambda].sub.EX] ([A.sub.340]) for each PET film based on the following equation for front-face reflection geometry used in this study :
The emission spectroscopy study was performed using a spectrofluorometer (ISA FluoroMax-2; Jobin Yvon-Spex, Edison, NJ); the spectral bandpass was fixed at 5 nm for monochromators
of both wavelengths of excitation and emission, and the recorded wavelength region is 300-500 nm at 280 nm excitation.
All fluorescence measurements were done on a fast scanning Varian O Cary Eclipse spectrofluorometer (USA), equipped with two Czerny-Turner monochromators
, a xenon flash lamp and connected to a PC microcomputer via an IEEE 488 (GPIB) serial interface.
Photoluminescence and excitation spectra were performed on a Fluorolog-3 spectrometer (HORIBA Jobin Yvon, Inc., NJ) with a 2nm slit width for both excitation and emission monochromators
. Fourier transform infrared spectroscopy (FT-IR) was performed on a Spectrum 400 (PerkinElmer, MA) to obtain IR spectra of V-Si QDs and SiQD@PS.
The energy used was 7,00021 keV, wavelength in the iron edge 1.77115 [Angstrom] with Si crystal monochromators
with special cuts for Si faces (111) with a peak at 16.4163 and FWHM 0.0038 degrees and Si (333) with a peak at 57.9353 and FWHM 0.0260 degrees.
As fluorescence analysis is normally conducted with two monochromators
at a 90[degrees] angle, any attenuation of the source of excitation (primary absorption effect) and subsequently any attenuation of the analytes fluorescence (secondary absorption effect) fall under the broad category of inner-filter effects (Yappert & Ingle 1989).
The steady state fluorescence emission measurements were obtained using a commercially available spectrofluorometer (Fluoromax-2, ISA; Jobin-Yuvon-Spex, Edison, NJ) and spectral band passes were kept as 5 nm in both excitation and emission monochromators
. The emission spectrum was recorded in the wavelength region 300-540 nm at 280 nm excitation.