Cu2O Nanoparticles for Application in Printed and Flexible Electronics

Abstract

This work reports the synthesis of cuprous oxide (Cu2O) nanoparticles (NP) and further application in conductive inks and resistive switching memory devices. A study was conducted on the used method to synthetize the NPs, to identify the influence of each parameter in the final morphology of the NPs. Also, two other studies focused on the stability of the NPs were conducted. In a first approach, non-volatile memories with MIM (Metal-Insulator-Metal) structure were produced on glass substrates. Contacts were made from gold deposited by e-beam and the insulator layer was made of organic compounds with NPs dispersed, deposited by spin-coating. The devices exhibited a unipolar switching, with an ON/OFF current ratio of approximately 103 and working voltages below 30V. Later, similar devices were produced on paper substrates, with intention to replicate the devices using flexible substrates. In this case, pen-writing printing was used method to deposit the newly optimized insulator layer of organic compounds and NPs. The new devices showed an ON/OFF current ratio of 104 and working voltages below 7V. Also 20 cycles were achieved into the opposing 5 achieved on glass produced devices, showing an improved stability and endurance. It was also demonstrated the formation of conductive copper films through reduction of the Cu2O NPs when dispersed in solvents containing glycerol, and recurring to annealing temperatures around 300ºC.