Dye-sensitisation of the photoconductivity of SiO₂films in M-dye-SiO₂-M structures

Abstract

Insulators such as SiO2 are not normally photosensitive except perhaps in the vacuum ultraviolet range. A photoresponse in the visible range can be stimulated by illuminating a dye in intimate contact with the surface of the insulator. This paper describes preliminary experiments on metal-SiO2-dye-metal sandwich structures. The induced photoconductivity has been measured as a function of wavelength, polarity and magnitude of the applied field using steady-state and pulse techniques. Relatively large electron currents are observed with a time response limited by instrumental factors. Estimates have been made of the quantum efficiency of electron injection under steady-state and pulse conditions. The phenomenon has possible device applications.