Photoelectrochemical properties of size-quantized semiconductor photoelectrodes prepared by two-dimensional cross-linking of monodisperse CdS nanoparticles

Two-dimensionally organized CdS nanoparticle films were prepared with the u se of Langmuir-Blodgett (LB) technique. Propanethiol-modified CdS nanoparti cles were spread on water subphase, which contained 1,6-hexanedithiol as a cross-linking agent for binding the surface-modified CdS nanoparticles with each other. Surface pressure-area isotherms of CdS monoparticle layer take n after the cross-linking were largely different from those obtained withou t addition of 1,6-hexanedithiol in water subphase. After the cross-linking, the CdS monoparticle layer was transferred from the air-water interface to 1,6-hexanedithiol-modified gold substrate using the LB technique to give C dS monoparticulate film electrodes with dense packing of the nanoparticles on the gold substrate. By repeating the same techniques, the monoparticulat e him was cumulated with desired amounts. The prepared CdS nanoparticle fil ms showed n-type photosensitivities in proportion to the cumulation number of the monoparticle layers for less than five layers. Beyond that value, a saturation tendency of the photocurrent appeared. (C) 2000 Elsevier Science Ltd. All rights reserved.