Band Edge Optical Excitation of Pyridine-Adsorbed CuAg Nanoparticles

Mokkath, Junais Habeeb

doi:10.1021/acs.jpca.8b03058

Cited by 3 publications

(3 citation statements)

References 68 publications

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“…It should be noted that there are always some physically adsorbed modifiers onto the surface of the CuNPs because excessive HDDP was added into the reaction system. [14][15][16][17][18] The amount of physical and chemical adsorbed DDP on the CuNPs are 4.6 × 10 −6 and 1.02 × 10 −5 mol m -2 , respectively (see Note S1 and Figure S1, Supporting Information). The presence of this organic modifier on the surface of the CuNPs is beneficial for our final goal because: i) it avoids CuNPs aggregation during the fabricated process and improves dispersibility in the solvent, which should result in a lower memristor-to-memristor variability; ii) it prevents the CuNPs from rapid oxidation, which should stabilize the electrical properties of the memristors, and iii) they can act as dopant, which should help to fine-tune the electrical properties of the memristors (i.e., switching voltages and state currents).…”

Section: Resultsmentioning

confidence: 99%

Nano‐Memristors with 4 mV Switching Voltage Based on Surface‐Modified Copper Nanoparticles

et al. 2022

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Memristors, i.e., short for resistor with memory, are electronic devices that can switch their electrical resistance between different levels depending on the external voltages applied. [1] The resistive switching (RS) phenomenon was first observed in the late 1960s in a two-terminal cell based on a phase-change material sandwiched by two electrodes, [2] and nowadays it has been observed in many other materials (e.g., metal-oxide, magnetic, and ferroelectric thin films). [3] The performance of memristors is characterized by the voltage, energy, and time that they need to switch, as well as by the resistance of each state, the stability of the state resistance over time (i.e., retention time), and the maximum number of cycles that it can switch (i.e., endurance). [4,5] Depending on the materials employed to fabricate the memristor its main figures-of-merit may vary, allowing its use in multiple applications, such as non-volatile memory, advanced computation, radiofrequency switches, and entropy source for encryption systems. [3,6] The use of memristors in the field of bioelectronics is highly desired because they could enormously simplify the structure of integrated circuits required for spiking signal detection [7] and event-driven operation [8] -i.e., two key functions in multiple products, such as e-skin and monitoring systems-plus they may enable more sophisticated functionalities, such as in-memory computing, [9] and neuromorphic computation by reverse engineering the brain. [10] As an example, reference [11] employed bio-compatible organic memristors to monitor the signal activity of neocortical pyramidal neurons from rats, and reference [12] reported a three-neuron brain-silicon network to emulate transmission and plasticity properties of real synapses. However, in such studies, a patch-clamp integrated circuit was required to amplify the bioelectronic signal from the living cells (i.e., 50-100 mV) to the operational voltages of the memristors (i.e., >2 V), which increased the complexity of the overall system. Therefore, fabricating memristors capable to operate at low bio-compatible voltages is highly attractive to simplify the circuitry and reduce the energy consumption of bioelectronic systems, which may enable their use in battery-less and selfpowered implants.Many studies have attempted the fabrication of memristors with ultralow switching voltages (see Table S1, SupportingThe development of memristors operating at low switching voltages <50 mV can be very useful to avoid signal amplification in many types of circuits, such as those used in bioelectronic applications to interact with neurons and nerves. Here, it is reported that 400 nm-thick films made of dalkyl-dithiophosphoric (DDP) modified copper nanoparticles (CuNPs) exhibit volatile threshold-type resistive switching (RS) at ultralow switching voltage of ≈4 mV. The RS is observed in small nanocells with a lateral size of <50 nm -2 , during hundreds of cycles, and with an ultralow variability. Atomistic calculations reveal that the switching mech...

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Section: Resultsmentioning

confidence: 99%

Nano‐Memristors with 4 mV Switching Voltage Based on Surface‐Modified Copper Nanoparticles

et al. 2022

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“…In this work, we want to comprehend how the optical properties of zeolites change in relation to modifications in shape or symmetry utilizing quantum simulations using the time‐dependent density functional theory (TDDFT). We remark that quantum simulations are worthwhile since unlike classical simulations they precisely incorporate quantum effects [30–40]. TDDFT has become a very popular technique for the calculation of excited‐state properties nowadays benefiting from its efficient numerical implementations.…”

Section: Introductionmentioning

confidence: 99%

Symmetry dependent optical properties of zeolites: A quantum mechanical study

Muhammed

Sibai

Chamkha

et al. 2023

Int J of Quantum Chemistry

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The outstanding structural and chemical characteristics of zeolites (porous crystal forms of aluminosilicate oxides) are well known, but little is known about their optical properties. In this work, we examine the impact of symmetry on the optical characteristics of zeolites utilizing quantum simulations via time‐dependent density functional theory. We demonstrate that zeolites with high symmetry (cubic ACO zeolite) absorb light in the visible spectrum, whereas zeolites with low symmetry (trigonal AFY zeolite) absorb light in the UV–vis region of the electromagnetic spectrum. Additionally, we reveal the nature of optical excitations by our analysis of the electron–hole distribution using transition density matrices. The zeolites also displayed significant variations in their electronic circular dichroism spectra, suggesting symmetry‐driven modulations. This theoretical work offers crucial information about the optical properties of zeolites.

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“…[19][20][21][22][23][24][25][26] Alloying of materials by adding one or more elements is driven by the prospect of improving the material's properties. [27][28][29][30][31][32][33][34][35][36][37] In this context, the incorporation of a fourth element to the M/A/X sites of ternary MAX phases was suggested as a potential technique to modify their characteristics. [38][39][40][41][42][43][44][45] Recent studies have led to the discovery of a new family of MAX phases with in-plane chemical order, coined i-MAX, 46,47 which includes new elements and expands the family of MAX phases.…”

Section: Introductionmentioning

confidence: 99%