Sol-gel derived In2S3 buffer layers for inverted organic photovoltaic cells

In2S3 - a wide-gap semiconductor - has been implemented in organic photovoltaics using an all-solution based sol gel route. Typically, indium sulfide is deployed as a buffer layer in copper indium sulfide (CIS) photovoltaic systems as electron-selective contact on the bottom electrode. We transferred this idea to organic, solution-processed photovoltaics, exploring its potential in an inverted hybrid device structure. The optical and morphological properties of the films were investigated by UV-Vis transmittance spectroscopy and scanning electron microscopy. The optical studies showed that the In2S3 films exhibit a band gap of similar to 2.25 eV. The effect of In2S3 film thickness on conversion efficiency of the device was also investigated. The device with the 158 +/- 5 nm of In2S3 film thickness provides the best performance with an average short-circuit current density (J(sc)) of approximately 7.96 +/- 0.12 mA/cm(2), open-circuit voltage (V-oc) of 0.609 +/- 0.007 V, fill factor (FF) of 0.49 +/- 0.014, and power conversion efficiency of 3.04 +/- 0.14%. (C) 2014 Elsevier Ltd. All rights reserved.