Novel Photoinduced Recovery of OFET Memories Based on Ambipolar Polymer Electret for Photorecorder Application

Abstract

A new design concept for novel photoresponsive flash organic field-effect transistor (OFET) memory is demonstrated by employing the carbazoledioxazine polymer (Poly CD) as an electret. Photoactive electrets that can absorb the light effectively rather than photoactive semiconductors are proposed by the "photo induced recovery" mechanism in the literature; however, the correlation between the chemical structure and photoresponsive electrical performances is ambiguous. In this study, it is reported for the first time that the OFET memory with trapped charges can be optically recovered by a polymer electret and the working mechanism can be explained by the structural design. The highly planar Poly CD electret exhibits photoluminescence quenching in film states, resulting in the generation of sufficient excitons to eliminate trapped charges under light excitation. Additionally, the Poly CD electret with coplanar donor-acceptor moieties is suitable for both p-channel and n-channel semiconductors. For p-type memory devices, a large memory window (82 V) and stable nonvolatile retention performance with high ON/OFF ratio could be obtained. The memories also display good switching reliability for voltage-programming and light-erasing cycles. This study provides useful information for the development of polymer-based photoresponsive flash OFET memories and demonstrates the practical applications of photorecorder and photosensitive smart tag.

High‐Performance Nonvolatile Organic Photonic Transistor Memory Devices using Conjugated Rod–Coil Materials as a Floating Gate

“…Also, the inherent bistable states or multi level storage can be achieved through modulating the charge density in an active channel by altering the external electric field or introducing photons. The use of floating-gate dielectrics, [18][19][20][21][22] polymer-based electrets, [23][24][25][26] and ferroelectric materials [27][28][29] as nonvolatile memories were employed in FET memory devices. In floating-gate-based FET memory devices, the nonvolatility characteristic was achieved by storing the charges in well-dispersed metallic or semiconducting materials that were located within an insulating gate dielectric layer.…”

“…[33] Previous investigations have successfully prepared memory layers using organic-inorganic hybrid composites, [20,34,35] polymer nanoparticles [22] or small molecules [31,36,37] dispersed in an insulating polymer host, and direct casting of photoactive polymer electret. [25,38] The memory behavior due to light illumination within the devices originates from dissociating the photon-induced excitons that are employed for recombination or act as trapped charges. Consequently, this modulates the conductance state in the active channel and results in favorable memory characteristics.…”

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

“…21 Nevertheless, recently, electrical programming/ photo-erasing OFET memories with photoinduced-reset characteristic are of great interest, because they offer a novel strategy for information acquisition in the eld of OFET optical memories. [24][25][26][27] For example, Liao and co-workers reported the 2D perovskite-based transistor-type photomemory using a 2D Cs 2 Pb(SCN) 2 Br 2 /polymer hybrid lm as the oating gate. 27 Compared to the conventional OFET-type memories modulated only by electrical bias, optical memories with "photoinducedreset" behavior can be erased by light-only bias that completely replace electrical stress to act as a charge erasing method to realize the memory behaviors of the OFET-type memories.…”

“…It can not only conveniently eliminate the stored charges and energy savings (bias-free erasing), but also extend application as a memory-related photosensor. [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.…”

“…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. Furthermore, at present, there are two possible operation principles explaining the "photoinduced reset".…”