Local potential distribution of macrophase separated polymer blend domains

Local surface potential measurements on alkoxy-substituted poly (p-phenylene ethynylene), poly (EHO-OPPE), as an electron transport material (ETM) and poly (triphenyl diamine), poly (TPD), as a hole transport material (HTM) and their blends in three different compositions (1 : 3, 1 : 1, 3 : 1) were performed by using scanning Kelvin force microscopy (SKFM). Simultaneously the topography of all surfaces was obtained using atomic force microscopy (AFM). In this paper, we propose a new principle for mapping out the local surface potential distributions of macrophase separated segments in the model polymer blend systems through the combined mode of intermittent contact AFM–SKFM techniques. The energetics and kinetics involved are also discussed in terms of potential distributions in the different phases of surface morphologies in the single-layered pristine as well as single-layered two component polymer blend systems. The experimental results provide considerable insight into the electrical/electronic properties of these ETM and HTM materials and reveal highly qualitative information for the first time to show a direct conformation of apparent work function difference between the ETM rich and HTM rich components. Finally, an attempt has been made to perform the combined approaches of valuable and high resolution complementary techniques such as scanning electron microscopy, absorption and photoluminescence spectra in order to correlate the observed contact potential difference/surface potential difference between the two rich ETM and HTM components obtained from microscopic and macroscopic scans.