1. School of Mechatronic Engineering and AutomationKey Laboratory of Advanced Display and System ApplicationsMinistry of EducationShanghai University Shanghai 200072 China
2. IEMNUMR8520Université de Lille 1 Villeneuve d'Ascq Cédex 59652 France
3. Light, Nanomaterials, Nanotechnologies (L2n) LaboratoryCharles Delaunay InstituteCNRSUniversity of Technology of Troyes 12 Rue Marie Curie Troyes Cedex F-10004 France
4. Department of PhysicsResearch Centre of Excellence for Organic Electronics and Institute of Advanced MaterialsHong Kong Baptist University 224 Waterloo Road Kowloon Tong Hong Kong China