The structure of titanyl phthalocyanine (TiOPc) thin films is correlated with photovoltaic properties of planar heterojunction solar cells by pairing different TiOPc polymorph donor layers with C 60 as an acceptor. Solvent annealing and the insertion of two different templating layers, namely 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) and CuI, prove to be effective methods to control the TiOPc thin film structure. The crystal phase of TiOPc thin films was identified by combining X-ray reflectivity (XRR) measurements with spectroscopic techniques, including absorption and micro-Raman measurements. Implementation of a donor layer with an absorption spectrum extending into the near-infrared (NIR) led to solar cells with external quantum efficiencies (EQEs) above 27% from λ = 600 - 890 nm, with the best device yielding a power conversion efficiency (PCE) of 2.6%. Our results highlight the need to understand the relationship between processing parameters and thin film structure, as these have important consequences on device performance.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physical and Theoretical Chemistry