1. Department of ChemistryFaculty of ScienceNational University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
2. Solar Energy Research Institute of Singapore, SERISNational University of Singapore (NUS) 7 Engineering Drive 1, Building E3A, #06-01 Singapore 117574 Singapore
3. Department of Materials Science and Chemical Physics and Institute of Theoretical and Computational Chemistry (IQTCUB)University of Barcelona c/Martí i Franquès 1 08028 Barcelona Spain