1. National Green Coating Equipment and Technology Research Centre Lanzhou Jiaotong University Lanzhou 730070 P. R. China
2. School of Materials Science and Engineering Lanzhou Jiaotong University Lanzhou 730070 P. R. China
3. State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 P. R. China
4. School of Materials Science and Engineering Tianjin University Tianjin 300072 P. R. China
5. Department of Chemical and Biological Engineering/Polymer Technology Chalmers University of Technology SE‐412 96 Göteborg Sweden