The goal of this project is to create a solar cell using charge-conducting polymer and mesoporous, crystalline titania.
The pores of the titania are first coated in a small organic molecule (the mediator) to convert the surface from hydrophilic to hydrophobic. Then, the hydrophobic polymer will diffuse from solution into the pores. The polymer we are currently employing is poly(3-hexylthiophene). Thus, the titania and the polymer form an interpenetrating network.
When sunlight hits the solar cell, an electron in the polymer becomes excited. It transfers to the titania through the mediator, and then to the cathode. Due to the interpenetrating network, the electron only has to diffuse a few nanometers to the titania.
The hole left behind in the polymer from the electron is filled by the anode, completing the circuit.
A final related project that we have been exploring is the use of self-organized nanoscale materials for the production of nanoscale rechargeable lithium batteries.1 In this work, the same ideas of surfactant templating, are used to produce colloidal versions of layered vanadia materials for incorporation into 3D nanoscale batteries. After synthesis, the surfactant is exchanged for an alkali cation to produce the final colloidal cathode material. The layered vanadia nanorolls are produced by a hydrothermally driven structural rearrangement in which layered vanadates exfoliate and then roll up into scroll like structures. Because we have extensively studied the process of nanoscale restructuring in related surfactant templated materials, we have been able to logically tune the nanoscale architecture of these vanadia nanorolls for optimal cathode performance.
1. D. Sun, C.W. Kwon, G. Baure, E. Richman, J. MacLean, B. Dunn, and S.H. Tolbert, “Vanadium Oxide Nanorolls as Cathode Materials for Rechargeable Batteries: The Relationship between Nanoscale Structure and Electrochemical Performance.” Adv. Func. Mater., 14, 1197-1204 (2004).