Abstract:
This paper presents a novel photoanode system of self-assembled hybrid Polyvinylcarbazole (PVK)–
titania nanocomposites (PVTs) using template guided polymerization in a mixed phase of rutile–anatase
titania nanotubes. Mixed crystalline phase of titania was prepared by aminolysis process through a
controllable capping mechanism. During vinyl carbazole (VK) addition, the charges present on the surface
of titania adsorb VK molecules and act as a template during propagation and allow the growing PVK
molecular chains adhere along the walls of the titania nanotubes via the combination of various noncovalent
interactions. UV–vis spectral band of PVT exhibited broad band with red shift revealing its
synergistic effect of harvesting photons. Morphological and XRD studies revealed the preservation of
tubular shape and mixed phase of rutile–anatase in PVT nanotubes. Dye sensitized solar cells (DSSCs)
were fabricated with PVTs as photoanode using N719 dye as the photo-sensitizer. Conduction mechanism
of the excited charge carriers in the device was studied by electrochemical impedance analysis. The
presence of mixed anatase–rutile titania phase enhanced the electron transfer thereby reducing the
charge recombination which is manifested from the studies made using individual phase of titania. PVT
based cell characteristics were optimized to be Voc¼0.83 V, Jsc¼12.01 mA/cm2, FF¼30.22 with an overall
power conversion efficiency of η¼3.03% which suggests that the present strategy can be exploited for the
development of efficient photoanode systems.
