a
Energy Research Institute @ NTU (ERI@N), Nanyang Technological University, 50 Nanyang Drive, Singapore 637553
E-mail: subodh@ntu.edu.sg
b
School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
E-mail: ACGrimsdale@ntu.edu.sg
c
Department of Chemistry – Ångström, Uppsala University, Box 523, 75120 Uppsala, Sweden
d
Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland