Mechanism studies on the superior optical limiting observed in graphene oxide covalently functionalized with upconversion NaYF₄ :Yb³⁺/Er³⁺ nanoparticles
Small. 2012 Jul 23;8(14):2163-8.
doi: 10.1002/smll.201200249.
Epub 2012 May 21.
1 Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.