1. Clean Energy Cluster, International Iberian Nanotechnology Laboratory (INL) Avenida Mestre Jose Veiga Braga 4715‐330 Portugal
2. Key Laboratory of Computer Vision and Systems (Ministry of Education), School of Computer Science and Engineering Tianjin University of Technology Tianjin 300384 China
3. School of Physics Shandong University Jinan 250100 China
4. Materials Science and Engineering Programme and Department of Mechanical Engineering The University of Texas at Austin Austin TX 78712 USA
5. School of Science China University of Geosciences Beijing 100083 China
6. Centre of Innovation in Engineering and Industrial Technology, Instituto Superior de Engenharia do Porto Instituto Politécnico do Porto Porto 4200–465 Portugal