Research ArticleMATERIALS SCIENCE

Temperature-resilient solid-state organic artificial synapses for neuromorphic computing

See allHide authors and affiliations

Science Advances  03 Jul 2020:
Vol. 6, no. 27, eabb2958
DOI: 10.1126/sciadv.abb2958
  • Fig. 1 Organic ECRAMs using ion gels enable submicrosecond switching in vacuum.

    (A) ECRAM device schematic. (B) Chemical structures of the channel/gate (left) and electrolyte (right) materials. The blue circle on 1-ethylimidazolium bis(trifluoromethylsulfonyl)imide (EIM:TFSI) highlights the hydrogen that renders EIM:TFSI protic.(C) Resistive switching characteristics of ECRAM with PEDOT:PSS as the channel/gate material and Aquivion as the electrolyte rapidly deteriorate when going from 20% relative humidity (RH) in N2 atmosphere (black) to 2 × 10−4 mbar vacuum (gray). (D) Cycling of ECRAM with PEDOT:PSS as the channel/gate material and EIM:TFSI poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as the electrolyte operating in vacuum. (E) Cycling of ECRAM with poly(2-(3,3-bis(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)-[2,2-bithiophen]-5-yl)thieno[3,2-b]thiophene) [p(g2T-TT)] as the channel/gate material and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM:TFSI) PVDF-HFP as the electrolyte operating in vacuum. Inset shows normalized channel conductance ΔGSD/Gmin for PEDOT:PSS-based (blue) and p(g2T-TT)-based (red) ECRAMs.

  • Fig. 2 Temperature-stable switching of organic ECRAMs, >109 write endurance at 90°C, and temperature-independent write linearity.

    Endurance of (A) PEDOT:PSS EIM:TFSI PVDF-HFP and (B) p(g2T-TT) EMIM:TFSI PVDF-HFP devices to >109 write-read events at 90°C (colored), followed by additional >109 write-read events at 30°C (black) using ±1-V 1-μs pulses. (C) Normalized synaptic weight update ΔGSD/Go dependence on injected charge ΔQ per area per write pulse. The dependence is linear at 30°C and at higher temperatures both during potentiation (squares) and depression (diamonds). The black dashed line is a linear fit. arb. stands for arbitrary units. (D) Time-resolved write current IGD measurements reveal a 6% increase in the amount of injected charge per write pulse at elevated 90°C temperature (red) compared to 30°C (black). All measurements were performed under 2 × 10−4 mbar vacuum.

  • Fig. 3 Device write speed and energy scaling and operation under <1-μs write-read cycles.

    Switching speed (open squares) and energy (solid squares) scaling of (A) PEDOT:PSS EIM:TFSI PVDF-HFP and (B) p(g2T-TT) EMIM:TFSI PVDF-HFP devices versus ECRAM channel area. Insets in (A) and (B) show no substantial difference in the switching characteristics of different size devices using scaled write duration. Device modeling (colored dashed lines) predicts that a 1 μm by 1 μm device will enable <20-ns switching with <10 fJ per write switching energy. (C) p(g2T-TT) EMIM:TFSI PVDF-HFP device potentiation and depression under ±2-V 200-ns write pulses (gray shaded area), followed by 100-ns write-read delay and +0.3-V 500-ns readout (orange shaded area). The horizontal dashed lines are a guide to the eye. All measurements were performed under 2 × 10−4 mbar vacuum.

Supplementary Materials

  • Supplementary Materials

    Temperature-resilient solid-state organic artificial synapses for neuromorphic computing

    A. Melianas, T. J. Quill, G. LeCroy, Y. Tuchman, H. v. Loo, S. T. Keene, A. Giovannitti, H. R. Lee, I. P. Maria, I. McCulloch, A. Salleo

    Download Supplement

    This PDF file includes:

    • Supplementary Materials and Methods
    • Figs. S1 and S7
    • Note S1
    • References

    Files in this Data Supplement:

Stay Connected to Science Advances

Navigate This Article