Tailoring memory performance via engineering conjugated bridges in benzo[c][1,2,5]thiadiazole based donor–acceptor small molecules

Abstract

Tuning the conjugated bridges between the electron-donor and electron-acceptor moieties plays a crucial role in enhancing the memristive properties of organic materials, yet it is rarely reported. Herein, we designed and synthesized four donor–acceptor (D-A) organic small molecules, namely 4,7-bis(4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)benzo[c][1,2,5]thiadiazole (DF-BT), 4,7-bis((4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)ethynyl)benzo[c][1,2,5]thiadiazole (DF- ynl-BT), 4,7-bis(5-(4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)thiophen-2-yl)benzo[c][1,2,5]thiadiazole (DF- Th-BT), and 4,7-bis((5-(4-((9H-fluoren-9-ylidene)(phenyl)methyl)phenyl)thiophen-2-yl)ethynyl)benzo[c][1,2,5]thiadiazole (DF- Th- ynl-BT), featuring unique conjugated bridges. These molecules were employed as active layers in resistive random-access memory (RRAM) devices to systematically investigate the influence of conjugation bridges on the electrical parameters. The results revealed that devices based on DF-BT, DF- ynl-BT, and DF- Th-BT exhibited write-once-read-many-times (WORM) characteristics, while the DF- Th- ynl-BT-based device demonstrated stable Flash-type switching behavior. Compared to DF-BT, memory devices utilizing DF- ynl-BT, DF- Th-BT, and DF- Th- ynl-BT, which incorporate additional conjugated bridges, exhibited nonvolatile memory properties with reduced threshold voltages, an improved ON/OFF current ratio, enhanced stability, and better uniformity. These findings demonstrated that tailoring the conjugated bridges in D-A molecules can effectively modulate resistive memory behavior and enhance device performance. Furthermore, the DF- Th- ynl-BT-based device was successfully integrated into logic gate circuits and display functions, highlighting its significant potential for applications in artificial intelligence (AI) neural networks.

Keywords

Memory device / Charge transfer / WORM / Flash / Conjugated bridge

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

CRediT authorship contribution statement

Xianglin Wang: Writing – original draft, Investigation. Hong Lian: Writing – review & editing, Conceptualization. Liang Zhao: Software, Data curation. Zhitao Qin: Methodology, Data curation. Yongge Yang: Visualization, Formal analysis. Tianxiao Xiao: Visualization, Formal analysis. Shuanglong Wang: Writing – review & editing, Supervision. Qingchen Dong: Supervision, Resources, Project administration, Funding acquisition.

Acknowledgements

This work was supported by the financial support from the National Natural Science Foundation of China (Grant Nos.: 62174116 and 61774109) and the start-up fund from Shanghai University.

References

[1] H. Yu, P.K. Zhou, X. Chen, Intramolecular hydrogen bonding interactions induced enhancement in resistive switching memory performance for covalent organic framework-based memristors, Adv. Funct. Mater. 33 (2023) 2308336.

[2] S. Möller, C. Perlov, W. Jackson, C. Taussig, S.R. Forrest, C. Taussig, S.R Forrest, A polymer/semiconductor write-once read-many-times memory, Nature 426 (2003) 166-169.

[3] B. Cho, S. Song, Y. Ji, T.W. Kim, T. Lee, Organic resistive memory devices: Performance enhancement, integration, and advanced architectures, Adv. Funct. Mater. 21 (2011) 2806-2829.

[4] W. Lu, C.M. Lieber, Nanoelectronics from the bottom up, Nat. Mater. 6 (2007) 841-850.

[5] Q.D. Ling, D.J. Liaw, C. Zhu, D.S.H. Chan, E.T. Kang, K.G. Neoh, Polymer electronic memories: Materials, devices and mechanisms, Prog. Polym. Sci. 33 (2008) 917-978.

[6] S. Miao, H. Li, Q. Xu, Y. Li, S. Ji, N. Li, L. Wang, J. Zheng, J. Lu, Tailoring of molecular planarity to reduce charge injection barrier for high-performance small-molecule-based ternary memory device with low threshold voltage, Adv. Mater. 24 (2012) 6210-6215.

[7] S. Balatti, S. Larentis, D.C. Gilmer, D. Ielmini, Multiple memory states in resistive switching devices through controlled size and orientation of the conductive filament, Adv. Mater. 25 (2013) 1474-1478.

[8] H. Li, Q. Xu, N. Li, R. Sun, J. Ge, J. Lu, H. Gu, F. Yan, A small-molecule-based ternary data-storage device, Chem. Soc. 132 (2010) 5542-5543.

[9] H. Wang, F. Meng, Y. Cai, L. Zheng, Y. Li, Y. Liu, Y. Jiang, X. Wang, X. Chen, Sericin for resistance switching device with multilevel nonvolatile memory, Adv. Mater. 25 (2013) 5498-5503.

[10] M. Mas-Torrent, C. Rovira, J. Veciana, Surface-confined electroactive molecules for multistate charge storage information, Adv. Mater. 25 (2013) 462-468.

[11] X.D. Zhuang, Y. Chen, G. Liu, B. Zhang, K.G. Neoh, E.T. Kang, C.X. Zhu, Y.X. Li, L.J. Niu, Preparation and memory performance of a nanoaggregated dispersed red 1-functionalized poly (N-vinylcarbazole) film via solution-phase self-assembly, Adv. Funct. Mater. 20 (2010) 2916-2922.

[12] N.G. Kang, B. Cho, B.G. Kang, S. Song, T. Lee, J.S. Lee, Structural and electrical characterization of a block copolymer-based unipolar nonvolatile memory device, Adv. Mater. 24 (2012) 385-390.

[13] Y. Zhang, H. Zhuang, Y. Yang, X. Xu, Q. Bao, N. Li, H. Li, Q. Xu, J. Lu, L. Wang, Thermally stable ternary data-storage device based on twisted anthraquinone molecular design, J. Phys. Chem. C 116 (2012) 22832-22839.

[14] H. Lian, X. Cheng, H. Hao, J. Han, M.T. Lau, Z. Li, Z. Zhou, Q. Dong, W.Y. Wong, Metal-containing organic compounds for memory and data storage applications, Chem. Soc. Rev. 51 (2022) 1926-1982.

[15] J. Liu, Z. Zeng, X. Cao, G. Lu, L.H. Wang, Q.L. Fan, W. Huang, H. Zhang, Preparation of MoS₂-polyvinylpyrrolidone nanocomposites for flexible nonvolatile rewritable memory devices with reduced graphene oxide electrodes , Small 8 (2012) 3517-3522.

[16] T.W. Kim, H. Choi, S.H. Oh, G. Wang, D.Y. Kim, H. Hwang, T. Lee, One transistor-one resistor devices for polymer non-volatile memory applications, Adv. Mater. 21 (2009) 2497-2500.

[17] S. Gao, X. Yi, J. Shang, G. Liu, R.W. Li, Organic and hybrid resistive switching materials and devices, Chem. Soc. Rev. 48 (2019) 1531-1565.

[18] Q.F. Gu, J.H. He, D.Y. Chen, H.L. Dong, Y.Y. Li, H. Li, Q.F. Xu, J.M. Lu, Multilevel conductance switching of a memory device induced by enhanced intermolecular charge transfer, Adv. Mater. 27 (2015) 5968-5973.

[19] S. Miao, H. Li, Q. Xu, N. Li, J. Zheng, R. Sun, J. Lu, C.M. Li, Molecular length adjustment for organic azo-based nonvolatile ternary memory devices, J. Mater. Chem. 22 (2012) 16582-16589.

[20] H. Zhuang, Q. Zhang, Y. Zhu, X. Xu, H. Liu, N. Li, Q. Xu, H. Li, J. Lu, L. Wang, Effects of terminal electron acceptor strength on film morphology and ternary memory performance of triphenylamine donor based devices, J. Mater. Chem. C 1 (2013) 3816-3824.

[21] J. Han, H. Lian, X. Cheng, Q. Dong, Y. Qu, W.Y. Wong, Study of electronic and steric effects of different substituents in donor-acceptor molecules on multilevel organic memory data storage performance, Adv. Electron. Mater. 7 (2021) 2001097.

[22] L. Yao, X. Cheng, W. Xia, L. Zhao, Z. Dou, H. Xue, H. Lian, Y. Qu, Q. Dong, Solution-processable star-shaped small molecules for efficient organic RRAM by induced conductive filament mechanism, J. Mater. Chem. C 10 (2022) 16687-16695.

[23] X. Cheng, H. Lian, L. Yao, W. Xia, J. Han, J. Fan, Q. Dong, W.Y. Wong, Enhanced intra/intermolecular charge transfer for efficient multilevel resistive memory, Appl. Surf. Sci. 599 (2022) 153877.

[24] H.C. Wu, J. Zhang, Z. Bo, W.C. Chen, Well-defined star-shaped donor-acceptor conjugated molecules for organic resistive memory devices, Chem. Commun. 51 (2015) 14179-14182.

[25] X. Chen, Z. Yang, W. Li, Z. Mao, J. Zhao, Y. Zhang, Y.C. Wu, S. Jiao, Y. Liu, Z. Chi, Nondoped red fluorophores with hybridized local and charge-transfer state for high-performance fluorescent white organic light-emitting diodes, ACS Appl. Mater. Interfaces 11 (2019) 39026-39034.

[26] Q. Bao, Q. Zhang, Y. Li, H. Li, J. He, Q. Xu, N. Li, D. Chen, J. Lu, Insertion of conjugated bridges in organic backbone for better multilevel memory performance: The role of alkynylgroup, Org. Electron. 28 (2016) 155-162.

[27] H. He, X. Shao, L. Deng, J. Zhou, Y. Zhu, H. Xia, L. Shen, F. Zhao, Triphenylamine or carbazole-based benzothiadiazole luminophors with remarkable solvatochromism and different mechanofluorochromic behaviors, Tetrahedron. Lett. 60 (2019) 150968.

[28] R. Balasaravanan, V. Sadhasivam, A. Siva, M. Pandi, G. Thanasekaran, C. Arulvasu, Synthesis, characterization and photophysical studies of d-π-A based conjugated triphenylamine derivatives, Chem. Sel. 1 (2016) 2792-2801.

[29] H. Fang, H. Gao, T. Wang, B. Zhang, W. Xing, X. Cheng, Benzothiadiazole-based d-π-A-π-D fluorophores: Synthesis, self-assembly, thermal and photophysical characterization, Dyes. Pigm. 147 (2017) 190-198.

[30] M.M. Rehman, H.M.M.U. Rehman, J.Z. Gul, W.Y. Kim, K.S. Karimov, N. Ahmed, Decade of 2D-materials-based RRAM devices: A review, Sci. Technol. Adv. Mater. 21 (2020) 147-186.

[31] Y.C. Lai, F.C. Hsu, J.Y. Chen, J.H. He, T.C. Chang, Y.P. Hsieh, T.Y. Lin, Y.J. Yang, Y.F. Chen, Transferable and flexible label-like macromolecular memory on arbitrary substrates with high performance and a facile methodology, Adv. Mater. 25 (2013) 2733-2739.

[32] Y. Sun, D. Wen, Logic function and random number generator build based on perovskite resistive switching memory and performance conversion via flexible bending, ACS Appl. Electron. Mater. 2 (2020) 618-625.

[33] G. Zhou, B. Sun, Z. Ren, L. Wang, C. Xu, B. Wu, P. Li, Y. Yao, S. Duan, Resistive switching behaviors and memory logic functions in single MnO_x nanorod modulated by moisture , Chem. Commun. 55 (2019) 9915-9918.

[34] H. Tan, G. Liu, H. Yang, X. Yi, L. Pan, J. Shang, S. Long, M. Liu, Y. Wu, R.W. Li, Light-gated memristor with integrated logic and memory functions, ACS Nano 11 (2017) 11298-11305.

[35] F. Zhou, B. Wu, H.L. Dong, Q.F. Xu, J.H. He, Y.Y. Li, J. Jiang, J.M. Lu, The application of a small-molecule-based ternary memory device in transient thermal-probing electronics, Adv. Mater. 29 (2017) 1604162.

[36] A. Barakat, H.J. Al-Najjar, A.M. Al-Majid, S.F. Adil, M. Ali, V.H. Masand, H.A. Ghabbour, H.K. Fun, Synthesis, X-ray diffraction, thermogravimetric and DFT analyses of pyrimidine derivatives, Molecules. 19 (2014) 17187-17201.

[37] H.E. Katz, A.J. Lovinger, J. Johnson, C. Kloc, T. Siegrist, W. Li, Y.Y. Lin, A. Dodabalapur, A soluble and air-stable organic semiconductor with high electron mobility, Nature 404 (2000) 478-481.

[38] H. Usta, C. Newman, Z. Chen, A. Facchetti, Dithienocoronenediimide-based copolymers as novel ambipolar semiconductors for organic thin-film transistors, Adv. Mater. 24 (2012) 3678-3684.

[39] C. Ye, Q. Peng, M. Li, J. Luo, Z. Tang, J. Pei, J. Chen, Z. Shuai, L. Jiang, Y. Song, Multilevel conductance switching of memory device through photoelectric effect, J. Am. Chem. Soc. 134 (2012) 20053-20059.

[40] Q. Zhang, G. Wang, H. Li, F. Zhu, H. Li, J. Lu, Improved molecular stacking and data-storage performance of pyridine- and pyrimidine-substituted small molecules, Adv. Funct. Mater. 28 (2018) 1800568.

[41] B.J. Ree, T. Isono, T. Satoh, Chemically controlled volatile and nonvolatile resistive memory characteristics of novel oxygen-based polymers, ACS Appl. Mater. Interfaces 12 (2020) 28435-28445.

[42] Z. Su, H. Zhuang, H. Liu, H. Li, Q. Xu, J. Lu, L. Wang, Benzothiazole derivatives containing different electron acceptors exhibiting totally different data-storage performances, J. Mater. Chem. C 2 (2014) 5673-5680.