Novel Organic Phototransistor-Based Nonvolatile Memory Integrated with UV-Sensing/Green-Emissive Aggregation Enhanced Emission (AEE)-Active Aromatic Polyamide Electret Layer

Abstract

A novel aggregation enhanced emission (AEE)-active polyamide TPA-CN-TPE with a high photoluminesence characteristic was successfully synthesized by the direct polymerization of 4-cyanotriphenyl diamine (TPA-CN) and tetraphenylethene (TPE)-containing dicarboxylic acid. The obtained luminescent polyamide plays a significant role as the polymer electret layer in organic field-effect transistors (OFETs)-type memory. The strong green emission of TPA-CN-TPE under ultraviolet (UV) irradiation can be directly absorbed by the pentacene channel, displaying a light-induced programming and voltage-driven erasing organic phototransistor-based nonvolatile memory. Memory window can be effectively manipulated between the programming and erasing states by applying UV light illumination and electrical field, respectively. The photoinduced memory behavior can be maintained for over 10 s between these two states with an on/off ratio of 10, and the memory switching can be steadily operated for many cycles. With high photoresponsivity ( R) and photosensitivity ( S), this organic phototransistor integrated with AEE-active polyamide electret layer could serve as an excellent candidate for UV photodetectors in optical applications. For comparison, an AEE-inactive aromatic polyimide TPA-PIS electret with much weaker solid-state emission was also applied in the same OFETs device architecture, but this device did not show any UV-sensitive and UV-induced memory characteristics, which further confirmed the significance of the light-emitting capability of the electret layer.

Recent Progress in Organic Phototransistors: Semiconductor Materials, Device Structures and Optoelectronic Applications

“…For instance, Cheng et al. inserted an aggregation enhanced emission (AEE)‐active aromatic polyamide TPA‐CN‐TPE electret film between the pentacene semiconducting layer and gate dielectric layer . The AEE‐active layer absorbed UV light and subsequently emitted strong green light, which could be absorbed by the top pentacene film to generate excitons.…”

Recent Advances in Organic Phototransistors: Nonvolatile Memory, Artificial Synapses, and Photodetectors

“…Photoluminescent polymers can be categorized as aggregation‐enhanced emission (AEE), aggregation‐caused quenching (ACQ), or aggregation‐induced emission (AIE) polymers. Cheng et al introduced an electret composed of an AEE‐active polyamide (TPA‐CN‐TPE) that emitted strong green light under UV irradiation [ 101 ] that could be subsequently absorbed by a pentacene channel. The photoinduced excitons in the channel could be separated with the assistance of gate bias, leading to significant shifts in the threshold voltage that could be considered photowriting.…”

Multilevel storage and photoinduced-reset memory by an inorganic perovskite quantum-dot/polystyrene floating-gate organic transistor

“…[24][25][26] In addition, beneting from the integration of photodetection and charge storage functions, the memory can possess remarkable advantages of excellent charge storage ability, data protection capability and the utilization of green energy in a single device. 21,28,29 Thus, the rapid development of optical memories is extremely signicant to the further development of their practical application. 1,16,25 Based on our knowledge, there are limited reports to study both the photoinduced-reset characteristic and multilevel storage of FGOFETMs based on IHP QDs/polymer composite lm as oating gates.…”