Pursuing Polymer Dielectric Interfacial Effect in Organic Transistors for Photosensing Performance Optimization

Abstract

Polymer dielectrics in organic field‐effect transistors (OFETs) are essential to provide the devices with overall flexibility, stretchability, and printability and simultaneously introduce charge interaction on the interface with organic semiconductors (OSCs). The interfacial effect between various polymer dielectrics and OSCs significantly and intricately influences device performance. However, understanding of this effect is limited because the interface is buried and the interfacial charge interaction is difficult to stimulate and characterize. Here, this challenge is overcome by utilizing illumination to stimulate the interfacial effect in various OFETs and to characterize the responses of the effect by measuring photoinduced changes of the OFETs performances. This systemic investigation reveals the mechanism of the intricate interfacial effect in detail, and mathematically explains how the photosensitive OFETs characteristics are determined by parameters including polar group of the polymer dielectric and the OSC side chain. By utilizing this mechanism, performance of organic electronics can be precisely controlled and optimized. OFETs with strong interfacial effect can also show a signal additivity caused by repeated light pulses, which is applicable for photostimulated synapse emulator. Therefore, this work enlightens a detailed understanding on the interface effect and provides novel strategies for optimizing OFET photosensory performances.

Assessment of the Factors Influencing Charge‐Carrier Mobility Measurements in Organic Field‐Effect Transistors

“…Such a decrease is consistent with the experimental finding that the measured mobilities are lower when using a polar dielectric compared to a non‐polar one. [4c,6,23a,24] When increasing σ or λ, the difference between µ sat and µ lin becomes larger, which is also consistent with the recent report from So and co‐workers. [4c] This can be understood on the basis that at a higher drain voltage, the carriers distribute away from the semiconductor‐dielectric interface and are thus comparatively less affected by the dielectric.…”

Understanding, Optimizing, and Utilizing Nonideal Transistors Based on Organic or Organic Hybrid Semiconductors

“…By utilizing this effect, OFET‐based photo‐stimulated synapse emulators have been demonstrated for brain‐inspired electronics and human–machine interfaces, etc. Figure illustrates a photo‐stimulated synapse emulator by employing the interfacial effect in OFETs with a range of organic semiconductors and polymer dielectrics . The molecular structures dominated the photosensing performance.…”

“…c) The output I D signals of the PLA‐DNTT‐OFET ( V G = −20 V, V D = −60 V) and the PAN‐DNTT‐OFET ( V G = −40 V, V D = −60 V) exposed to input light synaptic trains with light on time of 10 ms ( P = 1 mW cm −2 ) and off time of 500 ms and d) PPF index as a function of interspike interval. Reproduced with permission . Copyright 2017, Wiley‐VCH.…”

Light‐Stimulated Synaptic Transistors Fabricated by a Facile Solution Process Based on Inorganic Perovskite Quantum Dots and Organic Semiconductors

“…Light signal may enhance the computational speed by providing devices with high bandwidth, low power computation, and low crosstalk . Therefore, the development of artificial synapses stimulated by light signals is an interesting and essential branch for the implementation of future artificial intelligent systems . Thus far, some excellent works related to light‐stimulated synaptic transistors (LSSTs) have been reported.…”