PMID- 38174356
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20240121
IS  - 1944-8252 (Electronic)
IS  - 1944-8244 (Print)
IS  - 1944-8244 (Linking)
VI  - 16
IP  - 2
DP  - 2024 Jan 17
TI  - Volatile Memristive Devices with Analog Resistance Switching Based on 
      Self-Assembled Squaraine Microtubes as Synaptic Emulators.
PG  - 2539-2553
LID - 10.1021/acsami.3c13735 [doi]
AB  - In this work, the discovery of volatile memristive devices that exhibit analog 
      resistive switching (RS) and synaptic emulation based on squaraine materials is 
      presented. Specifically, organic microtubes (MTs) based on 
      2,4-bis[(4-(N,N-diisobutyl)-2-6-hydroxyphenyl]squaraine (SQ) are prepared by 
      evaporation-induced self-assembly (EISA). The MTs are ca. 2 mum in diameter 
      (aspect ratio: 10-130). While powder X-ray diffraction data for MTs identify 
      monoclinic and orthorhombic polymorphs, optical data report the monoclinic phase 
      with energetic disorder. By favorable energetic alignment of the Au work function 
      with the SQ HOMO energy, unipolar (hole-only) symmetric metal-insulator-metal 
      devices are formed by EISA of MT meshes on interdigitated electrodes. The DC I-V 
      characteristics acquired exhibit pinched hysteretic I-V loops, indicative of 
      memristive behavior. Analysis indicates Ohmic transport at low bias with carrier 
      extraction by thermionic emission. At high bias, space-charge-limited conduction 
      in the presence of traps distributed in energy, enhanced by a Poole-Frenkel 
      effect and with carrier extraction by Fowler-Nordheim tunneling, is observed. 
      These data indicate purely electronic conduction. I-V hysteresis attenuates at 
      smaller voltage windows, suggesting that carrier trapping/detrapping underpins 
      the hysteresis. By applying triangular voltage waveforms, device conductance 
      gradually increases sweep-on-sweep, with wait-time-erase or voltage-erase 
      options. Using square waveforms, repeated erase-write-read of multiple distinct 
      conductance states is achieved. Such analog RS behavior is consistent with trap 
      filling/emptying effects. By waveform design, volatile conductance states may 
      also be written so that successive conductance states exhibit identical current 
      levels, indicating forgetting of previously written states and mimicking the 
      forgetting curve. Finally, advanced synaptic functions, i.e., excitatory 
      postsynaptic current, paired-pulse facilitation, pulse-dependent plasticity, and 
      a transition from short- to long-term memory driven by post-tetanic potentiation, 
      are demonstrated.
FAU - Griffin, Karl
AU  - Griffin K
AUID- ORCID: 0000-0002-5963-0440
AD  - School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
FAU - Redmond, Gareth
AU  - Redmond G
AUID- ORCID: 0000-0002-0507-7707
AD  - School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
LA  - eng
PT  - Journal Article
DEP - 20240104
PL  - United States
TA  - ACS Appl Mater Interfaces
JT  - ACS applied materials & interfaces
JID - 101504991
SB  - IM
PMC - PMC10797587
OTO - NOTNLM
OT  - analog memristive device
OT  - charge-trapping memristor
OT  - electronic resistive switching
OT  - nanowire
OT  - neuromorphic computing
OT  - squaraine
OT  - synaptic emulation
COIS- The authors declare no competing financial interest.
EDAT- 2024/01/04 11:44
MHDA- 2024/01/04 11:45
PMCR- 2024/01/19
CRDT- 2024/01/04 04:25
PHST- 2024/01/04 11:45 [medline]
PHST- 2024/01/04 11:44 [pubmed]
PHST- 2024/01/04 04:25 [entrez]
PHST- 2024/01/19 00:00 [pmc-release]
AID - 10.1021/acsami.3c13735 [doi]
PST - ppublish
SO  - ACS Appl Mater Interfaces. 2024 Jan 17;16(2):2539-2553. doi: 
      10.1021/acsami.3c13735. Epub 2024 Jan 4.