1. Department of Chemical Engineering Texas Tech University Lubbock TX 79409 USA
2. Department of Electrical Engineering Nano‐optics and Biophotonics Lab University at Buffalo The State University of New York Buffalo NY 14260 USA
3. School of Materials Science & Engineering Wuhan Institute of Technology LiuFang Campus, No. 206, Guanggu 1st Road, Donghu New & High Technology Development Zone Wuhan 430205 P. R. China