Evidence for Photo-Switchable Carrier Mobilities in Blends of PbS Nanocrystals and Photochromic Dithienylcyclopentene Derivatives

Abstract

Abstract We use derivatives of the photochromic molecule 1,2-bis(5′-carboxy-2′-methylthien-3′-yl)-cyclopentene in combination with semiconducting PbS nanocrystals to probe the feasibility of solid-state optical switching in hybrid nanostructured thin films. X-ray photoelectron spectroscopy is applied to differentiate between the different constituents in the blends, while field-effect transistor measurements in the dark reveal the effect of prior illumination with visible or ultra-violet light on the transport properties. By analyzing the response of the electric conductivity, the carrier concentration and mobility separately, we are able to distinguish between the effect of additional photo-excited charge carriers and photo-induced changes of the electronic structure of the semiconducting film. Our results suggest that coupling between the nanocrystals and the photochromic molecule is weak but also provide evidence that photochromism of the molecules may be partially preserved.