1. Department of Micro & Nanotechnology; Middle East Technical University (METU); Ankara 06800 Turkey
2. Department of Polymer Science & Technology, METU; Ankara 06800 Turkey
3. Department of Metallurgical and Materials Engineering, METU; Ankara 06800 Turkey
4. Department of Chemistry, METU; Ankara 06800 Turkey
5. The Center for Solar Energy Research and Application, METU; Ankara 06800 Turkey