Fabrication and Characterization of Oriented P3HT/CdS Hybrid Thin Films Prepared by Friction Transfer for Organic Photovoltaics

Simple, low-cost one-step fabrication donor-acceptor hybrid thin films are highly desired for the practical realization of low-cost organic solar cells. In this work, oriented and hybrid thin films of P3HT/CdS were successfully fabricated by a solvent-free friction transfer (FT) method utilizing Cadmium xanthate [Cd(Xt)
2
] as CdS precursor and regioregular P3HT in a single step. Complete conversion of [Cd(Xt)
2
] to CdS with optical band gap of 2.53 eV after thermal annealing at 200 °C was confirmed by absorption spectral investigation. Polarized absorption spectral results revealed that FT-processed hybrid thin films of P3HT/CdS were oriented and extent of molecular orientation was enhanced after the thermal annealing at 200 °C. Highly oriented hybrid thin films with dichroic ratio of 6.95 was prepared under the optimum fabrication conditions such stage speed, stage temperature and applied load of 1200 mm/min, 85°C and 2.4 kg, respectively.