Supporting Information Augmenting n-type Performance of ambipolar Top- Contact Organic Thin-film Transistors by Self- generated Interlayers Tanmoy Sarkar † , Jane Vinokur † , Basel Shamieh † , Victoria Savikhin #‡ , Michael F. Toney # and Gitti L. Frey* † † Department of Materials Science and Engineering, Technion—Israel Institute of Technology, Haifa 32000, Israel # SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Building 137, Menlo Park, California 94025, United States ‡ Electrical Engineering Department, Stanford University, 350 Serra Mall, Stanford, CA 94305, United States Figure S1: Absorption spectrum of a pristine DPP-T-TT film on quartz. Inset shows the onset of the absorption spectrum and corresponding extrapolation for band-gap value extraction. (Measurement performed using a Varian Cary 100 scan UV−vis spectrophotometer).