1. Electrical Engineering and Computer Sciences, University of California at Berkeley, Berkeley, California 94720, USA
2. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
3. Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, 639798 Singapore
4. Materials Science and Engineering, University of California at Berkeley, Berkeley, California 94720, USA
5. The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
6. Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong, China