College of Physics and State Key Laboratory of Bio-Fibers and Eco-Textiles Qingdao University Qingdao 266071 People's Republic of China;
College of Electromechanical Engineering Qingdao University of Science and Technology No.99 Songling Road Qingdao 260061 Shandong People's Republic of China;
School of Materials Science and Engineering Shandong University of Science and Technology Qingdao 266590 People's Republic of China;
School of Materials Science and Engineering Shandong University Jinan 250061 People's Republic of China;
Centre for Clean Energy Technology University of Technology Sydney Broadway Sydney NSW 2007 Australia;