1. Department of Physics, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
2. Department of Solar Energy, School of Technology, Pandit Deendayal Energy University, Gandhinagar, Gujarat 382007, India
3. Group for Molecular Engineering of Functional Materials, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL Valais Wallis), CH-1951 Sion, Switzerland