Single-component near-infrared phototransistors based on ambipolar organic semiconductor nanowires have been investigated and compared with their corresponding thin-film counterparts. The nanowire organic phototransistors (NW-OPTs) showed photocurrent/dark-current ratios and photoresponsivities as high as 1.3 × 10(4) and 440 mA W(-1) for the p-type channel, and 3.3 × 10(4) and 70 mA W(-1) for the n-type channel, respectively, upon near-infrared illumination with an intensity of 47.1 mW cm(-2). These were much higher values compared to their thin-film counterparts. The enhancement of the near-infrared photoresponse could be attributed to the larger trap density originating from the semiconductor/insulator interface and the semiconductor/air interface. The performance of NW-OPTs was demonstrated to open up new possibilities to improve the near-infrared photoresponse of single-component devices.

The performance of organic thin film transistors (OTFTs) is heavily dependent on the interface property between the organic semiconductor and the dielectric substrate. Device fabrication with bottom-gate architecture by depositing the semiconductors with a solution method is highly recommended for cost-effectiveness. Surface modification of the dielectric layer is employed as an effective approach to control film growth. Here, we perform surface modification via a self-assembled monolayer of silanes, a spin-coated polymer layer or UV-ozone cleaning, to prepare surfaces with different surface polarities and morphologies. The semiconductor is inkjet-printed on the surface-treated substrates as single-line films with overlapping drop assignment. Surface morphologies of the dielectric before film deposition and film morphologies of the inkjet-printed semiconductor are characterized with polarized microscopy and AFM. Electrical properties of the films are studied through organic thin-film transistors with bottom-gate/bottom-contact structure. With reduced surface polarity and nanoscale aggregation of silane molecules on the substrates, semiconductor nucleates from the interior interface between the ink solution and the substrate, which contributes to film growth with higher crystal coverage and better film quality at the interface. Surface treatment with hydrophobic silanes is a promising approach to fabrication of high performance OTFTs with nonpolar conjugated molecules via solution methods.

The weak signal from rare event is readily submerged in the background and thus results in substantial challenges in its detection, which spurs researchers to decrease the surroundings background of detectors as low as possible. To this end, a low-background non-adhesive polytetrafluoroethylene (PTFE) flexible copper-clad laminate (PTFE-FCCL) was prepared by surface treatment. Specifically, the PTFE substrate was processed by ion implantation and the transition layer deposition; the adhesion between PTFE and copper of PTFE-FCCL is found to remain stable after barely immersing in liquid nitrogen. Furthermore, the surface morphology and the dielectric properties of the substrate were characterized and tested. The results presented herein offer a novel method to fabricate electronic substrates that can facilitate rare event detection.