THIN FILM WSE2 PHOTOELECTRODES

A PRIMARY LIMITATION OF PHOTOELECTROCHEMICAL CELLS IS PHOTOCORROSION OF ELECTRODE MATERIALS. ONE SOLUTION TO THISPROBLEM HAS BEEN TO APPLY ELABORATE CONDUCTING POLYMERIC COATINGS TO SENSITIVE ELECTRODES. AN ALTERNATIVE IS TO USE CORROSION RESISTANT ELECTRODE MATERIALS. GROUP VI METAL DICHALCOGENIDES, AND TUNGSTEN DISELENIDE (WSE2) IN PARTICULAR, HAVE SHOWN PROMISE AS INTRINSICALLY CORROSION RESISTANT PHOTOELECTRODE MATERIALS WITH GOOD PHOTOEFFICIENCIES. UNFORTUNATELY, VARIABLE QUALITY OF THE MATERIALS, RESULTING FROM CURRENT GROWTH TECHNIQUES, HAS RESULTED IN REDUCED PHOTOEFFICIENCIES DUE TO ELECTRON-HOLE RECOMBINATION AT GRAIN BOUNDARIES. THE MATERIALS QUALITY PROBLEM CURRENTLY AFFLICTING THESE METAL DICHALCOGENIDES HAS PREVENTED THEIR COMMERCIALIZATION IN PHOTOELECTROCHEMICAL SYSTEMS. ATM HAS DEMONSTRATED STATE-OF-THE-ART CAPABILITY IN METALORGANIC CHEMICAL VAPOR DEPOSITION (MOCVD) AND IN PHASE I PROPOSES TO PREPARE HIGH PURITY, SINGLE CRYSTAL TUNGSTEN DISELENIDE THIN FILMS BY MOCVD. WE BELIEVE THAT THESE HIGH QUALITY SINGLE CRYSTAL FILMS WILL HAVE IMPROVED PHOTOCONVERSION EFFICIENCIES DUE TOREDUCED SURFACE GRAIN BOUNDARIES. THE SINGLE CRYSTAL TUNGSTEN DISELENIDE FILMS WILL THEN BE USED AS PHOTOELECTRODES IN A PHOTOELECTROCHEMICAL CELL. IN PHASE II, THE PROCESS WILL BE SCALED AND THE DEMONSTRATION OF IMPROVED PHOTOEFFICIENCIES IN WSE2 CELLS WILL BE CONFIRMED THROUGH THE CONSTRUCTION AND DELIVERY OF PROTOTYPES TO THE DOE.