1. School
of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
2. School
of Physical and Mathematical
Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
3. Singapore-Berkeley Research Initiative for Sustainable Energy (SinBeRISE), 1 Create Way, Singapore 138602
4. Energy
Research Institute @ NTU (ERI@N), Nanyang Technological University, 50 Nanyang Drive, Singapore 637533
5. Institute of Materials for Electronic Engineering II, RWTH-Aachen, Sommerfeldstraße 24, D-52074 Aachen, Germany