Volume photodeposition processes in amorphous selenium hydrosols

Abstract

A photodeposition process adapted to the preparation of thin fillS of amorphous Selenium (a-Se) has been investigated previously. This communication gives the results of kinetic experiments performed on the a-Se-hydrosol under photoexcitation. The investigation reveals two distinct effects occurring in the bulk of the irradiated hydrosol i. e., photoprecipitation and photocoagulation. This result allows us to enhance our understanding of the photodeposition process.

<title>Holographic gratings recorded by photodeposition of inorganic colloids</title>

“…By irradiation of the solution in the cuvette, a-Se will be photodeposited on the front and back surfaces, in accordance to the process given in Eq. (8). However, in this case a-Se is catalyzed by the colloidal particles8.…”

“…Se03 (aq) 2Na2 SO3 (aq) Se + 2Na2 SO4 (a) j2 (8) In order to obtain reproducible PD results, the freshly prepared colloids are aged at 4°C for two days to make them metastable. For optical recording, the colloidal solution was equilibrated at room temperature and poured into polymethylmethacrylate (PMMA) spectroscopic cuvettes.…”

On the theory of photoadsorption kinetics of a-Se colloids: The thermal activation energy and compensation effect

“…A lowering of adsorption efficiency with the increase in light intensity can be understood as an effective closing of adsorption channels for the deposition process. Indeed, when the light intensity is high, the colloidal photoagglomeration effects [8] near the surface may compete strongly with the SP process.…”

Optical Photorecording By The Surface Photodeposition Effect

“…' The photons have been shown to cause several processes such as photoadsorption, photocoagulation, and photosedimentation. 5 The VP imaging effects were discussed previously.' The SP is caused by photon-enhanced adsorption of colloid particles due to the thermal Brownian agitation near the substrate.'…”