Nano-porous Poly(3-hexylthiophene) films: A novel route to prepare bulk heterojunction photovoltaic devices

ORAL

Abstract

Conjugated polymers are excellent candidates for use in low-cost electronics and photovoltaics applications. Bulk heterojunction (BHJ) morphologies are promising device architecture as the close proximity of the electron donor and acceptor micro-domains (with domain size comparable with the exciton diffusion length) facilitates the charge transport process. In order to achieve a well ordered BHJ architecture, poly(3-hexylthiophene) (P3HT) based rod-coil copolymers are synthesized where coil blocks are grafted to the P3HT chain through a cleavable linker. The linker and the attached sacrificial coil block can easily be cleaved and removed by chemical treatment leaving a rough nano-porous P3HT film. Scanning force microscopy and grazing incidence small angle X-ray scattering convincingly show the nano-pore formation. Further, depth profiling using dynamic secondary ion mass spectroscopy indicates that nano-pores probably penetrate the entire depth of the film (device thickness). Subsequently refilling of the nano-pores by electron transporting component (fullerene derivatives) provides the required device morphology.

–

Authors

  • Tirtha Chatterjee

    Mitsubishi Chemicals-Center for Advanced Materials, Materials Research Laboratory, University of California, Santa Barbara, CA 93106, UC Santa Barbara

  • Kulandaivelu Sivanandan

    Mitsubishi Chemicals-Center for Advanced Materials, Materials Research Laboratory, University of California, Santa Barbara, CA 93106

  • Craig J. Hawker

    Mitsubishi Chemicals-Center for Advanced Materials, Materials Research Laboratory, University of California, Santa Barbara, CA 93106

  • Ed Kramer

    UCSB - MC CAM, Department of Materials and Chemical Engineering, University of California Santa Barbara, University of California, Santa Barbara, Mitsubishi Chemicals-Center for Advanced Materials, Materials Research Laboratory, University of California, Santa Barbara, CA 93106, UCSB, Materials Research Laboratory, University of California, Santa Barbara, Materials Department, UCSB, University of California Santa Barbara