[1] Univ Malaya, Fac Sci, Dept Phys, LDMRC, Kuala Lumpur 50603, Malaysia
[2] Natl Univ Sci & Technol, US Pakistan Ctr Adv Studies Energy, H-12, Islamabad, Pakistan
[3] Natl Univ Sci & Technol, Sch Mech & Mfg Engn, H-12 Campus, Islamabad, Pakistan
[4] Univ Malaya, Fac Sci, Inst Biol Sci, Kuala Lumpur 50603, Malaysia
[5] Tokyo Inst Technol, Dept Phys Elect, Meguro Ku, 2-12-1 O Okayama, Tokyo 1528552, Japan
[6] Univ Cambridge, Dept Chem Engn & Biotechnol, Philippa Fawcett Dr,West Cambridge Site, Cambridge CB3 0AS, England