Copper (II) Phthalocyanine (CuPc) Based Optoelectronic Memory Device with Multilevel Resistive Switching for Neuromorphic Application

Abstract

The 1D nanotubular organic semiconductor, copper (II) phthalocyanine (CuPc), embedded in poly‐methyl methacrylate (PMMA) is employed for the first time for multilevel resistive switching (RS) and neuromorphic applications. Single–double bonded planar CuPc tubes are synthesized via simple solvothermal methods and dispersed in the PMMA solution with different weight concentrations. The composite sample is deposited on an ITO coated transparent, flexible and conducting PET substrate to form Ag/CuPc@PMMA/ ITO device. I–V characterizations of the cell reveal a formation free, bipolar, non‐volatile, multilevel RS effect. The device shows a significantly large resistance ON/OFF ratio of 104, low threshold operating voltage (<2 V), large endurance (>104 cycles) and long retention time (>104 s) at room temperature. The multilevel resistive states are induced by visible light illumination. Based on the experimental data, the conduction mechanism of this type of RS memory device under the optical and the electrical impulse is attributed by the charge trapping and detrapping methods. The synaptic short‐term and long‐term potentiation are also studied on the device during the identical pulse training process. The proposed RS active material is a potential candidate for future artificial neural systems that simulate characteristics of human memory.

Understanding the Site‐Selective Electrocatalytic Co‐Reduction Mechanism for Green Urea Synthesis Using Copper Phthalocyanine Nanotubes

“…The CuPc NTs were synthesized by ethylene glycol assisted solvothermal technique in our earlier report with some modifications [ 32 ] (Figure 1a and Experimental Section). The role of ethylene glycol for the synthesis of metal phthalocyanine is explained in our previous work.…”

Transparent Optoelectronic Synapse Based on a CuI Electrode for Arithmetic Operation

“…It can be seen that the device exhibited a sensitive response to the light stimulation, and the response time of the device was about 0.44 s (Figure b). The photocurrent reached a maximum value of 46.2 nA and then decayed very slowly after the light pulse, which could be maintained for about 25 s. To explain this observed phenomenon, Figure c gives the band energy alignment of ITO, CuPc, and CuI materials obtained from the literature. − Under light stimulation, photon-generated excitons (electron–hole pairs) were separated in the CuPc layer and migrated to the electrodes under the applied electric field. The CuI layer, a p-type semiconductor, contacted the CuPc layer, resulting in the formation of a p–p heterostructure.…”

Electrosynthesis of Green Urea by co-reduction of N2 and CO2 Using Dual Active Sites of Copper Phthalocyanine Nanotube

“…Thus, the gain of charge on Cu center due to neighboring adsorbed N 2 is the reason for lowering of free energy for *COOH (*NN), which improves the ease of CO 2 electroreduction. The CuPc NTs were synthesised by ethylene glycol assisted solvothermal technique in our earlier report [27] [Figure 1a & see the SI for details]. The role of ethylene glycol for the synthesis of metal phthalocyanine is explained in our previous work [22].…”