A planar integrated photometer/refractometer using an organic light emitting diode light source and an organic photovoltaic detector

Abstract

A simple refractometer/photometer is described which uses a vacuum-deposited multilayer organic light emitting diode (OLED) light source and a vacuum-deposited planar heterojunction organic photovoltaic (OPV) detector, separated from each other on a thin glass attenuated total reflectance (ATR) element by 1-2 cm. A portion of the light output from the OLED light source is internally reflected in the ATR element, and the evanescent field from this internally reflected light interacts with solutions of variable refractive index in the region between the OLED and OPV. We document here the simple construction principles for devices of this type, and the characterization of the operation of this first-generation device in terms of i) photocurrent in the OPV detector versus light output from the OLED and ii) the response of the device to solutions of differing refractive index. In these first-generation devices we estimate a sensitivity to changes in refractive index of +/- of 10 -3 units.