Hexagonal columnar liquid crystals as a processing additive to a P3HT:PCBM photoactive layer

• Published in: New journal of chemistry Vol. 39; no. 11; pp. 8439 - 8445
• Main Authors: , Krishna Pai, Ranjith
• Format: Journal Article
• Language: English
• Published: 01.01.2015
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c5nj01350j

Morphology of the donor/acceptor network in the photoactive layer is critical in order to optimize the device performance. In the present study, a new trihydrazone-functionalized cyanopyridine (CPTH-D16) demonstrating an ambient temperature hexagonal columnar liquid crystalline phase is introduced into the well-known photoactive layer i.e. P3HT:PCBM as a processing additive towards the construction of an efficient solar cell. Photon absorption and emission properties of the blends in the solution/film state are systematically investigated by UV-visible and fluorescence spectroscopy. Furthermore, surface morphology, the degree of crystallinity, changes in nanostructure, and the conductivity of blend films are determined through epi-fluorescence and atomic force microscopy. It is observed that the addition of the CPTH-D16 liquid crystal drastically increases the TUNA current passing through the P3HT:PCBM film. Here, the structural anisotropic nature of CPTH-D16 material helps to obtain well-ordered morphology with nanostructured crystallite formation as well as enhanced current in the P3HT:PCBM film. Trihydrazone-functionalized cyanopyridine liquid crystals are introduced into the photoactive layer as processing additives to acquire an improved interpenetrating network and charge carrier mobility.