1. Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin, Campinas, SP 13083-859, Brazil
2. Alan MacDiarmid NanoTech Institute, University of Texas at Dallas, Richardson, Texas 75080, United States
3. Universidade Estadual de Campinas, Instituto de Química, Campinas, SP 13083-970, Brazil
4. Materials Science and Engineering Department, University of Texas at Dallas, Richardson, Texas 75080, United States