Thiophene and Selenophene Donor–Acceptor Polyimides as Polymer Electrets for Nonvolatile Transistor Memory Devices

Abstract

We report the nonvolatile memory characteristics of n-type N,N ′-bis(2-phenylethyl)perylene-3,4:9,10-tetracarboxylic diimide (BPE-PTCDI) based organic field-effect transistors (OFET) using the polyimide electrets of poly[2,5-bis(4-aminophenylenesulfanyl)selenophene–hexafluoroisopropylidenediphthalimide] (PI(APSP-6FDA)), poly[2,5-bis(4-aminophenylenesulfanyl)thiophene–hexafluoroisopropylidenediphthalimide] (PI(APST-6FDA)), and poly(4,4′-oxidianiline-4,4′-hexafluoroisopropylidenediphthalic anhydride) (PI(ODA-6FDA)). Among those polymer electrets, the OFET memory device based on PI(APSP-6FDA) with a strong electron-rich selenophene moiety exhibited the highest field-effect mobility and Ion/Ioff current ratio of 105 due to the formation of the large grain size of the BPE-PTCDI film. Furthermore, the device with PI(APSP-6FDA) exhibited the largest memory window of 63 V because the highest HOMO energy level and largest electric filed facilitated the charges transferring from BPE-PTCDI and trapping in the PI electret. Moreover, the charge transfer from BPE-PTCDI to the PI(APSP-6FDA) or PI(APST-6FDA) electrets was more efficient than that of PI(ODA-6FDA) due to the electron-donating heterocyclic ring. The nanowire device with PI(APSP-6FDA) showed a relatively larger memory window of 82 V, compared to the thin film device. The present study suggested that the donor–acceptor polyimide electrets could enhance the capabilities for transferring and store the charges and have potential applications for advanced OFET memory devices.

Multilevel nonvolatile transistor memories using a star-shaped poly((4-diphenylamino)benzyl methacrylate) gate electret

“…In general, the transistor memories exhibit reversible cyclic transfer characteristics with an obvious hysteresis upon their dual sweeps because the trapped charges could be de-trapped or recombined by the charges injected from the organic semiconductors. [13][14][15][16][17][18][19][20] However, our BPE-PTCDI transistor memory device that contains a star-PTPMA electret exhibits an irreversible switching behavior that originates from the electrondonating nature of the pendent triphenylamine moieties and the coexisting energy level alignment at the interfaces. In addition, there are no obvious changes in the mobility and the ON/OFF current ratio of the transistor device, which implies that no additional traps are created in the interface except for the stored charges.…”

“…[1][2][3][4][5]10 The storage of charge in a transistor dielectric can be achieved using chargeable polymer electrets, [13][14][15][16][17][18][19][20] organic ferroelectric oriented-dipole dielectric materials, [21][22][23] and nanoparticles embedded or nanostructured gate dielectrics. [24][25][26][27][28] An electret is a dielectric material that has a quasi-permanent electric charge.…”

“…However, the above efforts have focused on linear polymeric systems with aromatic p-conjugated pendent moieties as the electret materials for transistor memory devices. [13][14][15][16][17][18][19][20] In addition, the majority of the aforementioned transistor memories that employed the polymer electret dielectric were limited to possess two-level memory characteristics. [13][14][15][16]18 Advanced nonvolatile memory technology can have more than 1 bit in each of the cells by increasing the levels of the channel current.…”

Nonvolatile memories using the electrets of conjugated rod-coil block copolymer and its nanocomposite with single wall carbon nanotubes

“…[9][10][11][12][13] A typical conguration of OFET memory devices is a conventional transistor with an additional charge storage layer (named as the electret) between the semiconductor layer and dielectric layer. [21][22][23][24][25][26] Among the studied electrets, the polymer-based electrets have the advantages of low cost and solution processability compared to the metallic nano-oating gate, which requires multiple procedures for preparing well-dispersed nanoparticles. [21][22][23][24][25][26] Among the studied electrets, the polymer-based electrets have the advantages of low cost and solution processability compared to the metallic nano-oating gate, which requires multiple procedures for preparing well-dispersed nanoparticles.…”

Theoretical Study of σ-π Conjugated Semiconductors Based on cis- and trans-Cyclopropane Derivatives

“…[12,13] Among them, σ electrons could not only delocalize in π-conjugated system through σ-π interactions to tune the electric structure, but also improve the solubility, thermal and optical stability. These σ-π conjugated semiconductors were potential candidates for application in organic field-effect transistors (OFETs) [14] and organic light-emitting diodes (OLEDs). [15,16] In this regard, the quest for new σ block based conjugated materials can be attributed to deeply uncovering physical organic properties of σ-π conjugated semiconductors and further exploring their novel properties and applications via theoretical and experimental study.…”