1. Polymer
Energy Materials Laboratory, School of Applied Chemical Engineering, Chonnam National University, Gwangju 500-757, South Korea
2. Department
of Materials Science and Engineering and Optoelectronics Convergence
Research Center, Chonnam National University, Gwangju 500-757, South Korea
3. Thin
Film Materials Laboratory, Department of Physics, Shivaji University Kolhapur, 416 004, India