1. College of Chemistry, Chemical Engineering and Materials ScienceCollaborative InnovationCenter of Suzhou Nano Science and TechnologySoochow University Suzhou 215123 China
2. Materials Sciences DivisionLawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA
3. Molecular FoundryLawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA
4. Department of Physics and AstronomyCollaborative Innovation Center of IFSA (CICIFSA)Shanghai Jiaotong University Shanghai 200240 P. R. China
5. Polymer Science and Engineering DepartmentUniversity of Massachusetts Amherst MA 01003 USA
6. Beijing Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical Technology Beijing 100029 China