Remplacement d'un phosphorimètre/ Replacement of a phophorimeter

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This request is for the replacement of a phosphorimeter. This instrument consists of a pulsed source of light, an excitation monochromator, a sample chamber, an emission monochromator, and a detector. Upon light excitation, the sample absorbs this light at a given wavelength and may re-emit light as a processus of relaxation. One type of emitted light is called phosphorescence; the other one is called fluorescence. Therefore one can used this phenomenon to monitor the behaviour of the molecule or the material upon light excitation. The crucial part of this instrument is the pulsed source, typically starting at 1 microsecond. One can then monitor the intensity of the emitted phosphorescence vs time and extract its the lifetime. One can also record the (phosphorescence) spectra at delay time greater than one microsecond and monitor the evolution of the spectra with time hence allowing to see whether more than one species is involved in the relaxation process. The goal of the research is to design new polymers for photocell applications and new photo-catalysts for hydrogen evolution. In photocell design, molecules and polymers are synthesized and analyzed for their emission properties, including both fluorescence and phosphorescence. The efficiency of the photocells will depend on the speed at which the light energy is aborbed and distributed in the material and at which the electron transfer, inducing an electric current, is done. On the photoinduced hydrogene evolution side, the efficiency will depend on the same parameters within the photocatalysts. The latters are made of platinum complexes which is well known of hydrogen evolution. With heavy metals, materials are prone to exhibit phosphorescence. In order to measure the rates of excitation energy migration and electron transfer in a material of a compounds, the monitoring of the phosphorescence (and fluorescence) properties (intensity and spectra) is necessary. This instrument is dedicated to phosphorescence.