A Light-Responsive Molecular Dielectric Surface for Ultraviolet-Selective Organic Optoelectronic Artificial Synapses

X-ray photoelectron spectroscopy (XPS) was performed with a K-Alpha Thermo Fisher for surface chemical composition measurement. Fourier transform infrared (FTIR) spectra were recorded on a Nicolet iS50 Fourier Transform instrument with a DTGS KBr detector (Thermo Fisher Scientific, USA). For each FTIR spectrum, 32 scans in the range 4000–400 cm−1 were recorded, with a resolution of 2 cm−1. Surface physical morphologies was inspected using a Dimension-3100 atomic force microscope (AFM). The optical absorption spectra were characterized using a Shimadzu UV2600 ultraviolet visible (UV-Vis-NIR) spectrometer. The Ph-BTBT-12 thin films with different interface modifications were characterized by scanning electron microscope (SEM, TESCAN Mira3). Electrical measurements of the OFET devices were carried out at room temperature under the atmosphere using a Keithley 4200-SCS semiconductor parameter analyzer and a Signatone S-1160 probe station. Device characteristics were measured under a 30 mW cm−2 UV lamp (λ=365 nm).