An electroconductive ink containing the reduced graphene oxide-metal oxide-carbon nanotube semiconductor applied to flexible electronic circuits

We present an interesting low-cost, green, and scalable technique for direct ink writing for flexible electronic applications different from traditional fabrication techniques. In this work, a reduced graphene oxide (RGO)-bismuth oxide (Bi₂O₃)/carbon nanotube (CNT) (RGBC) ternary conductive ink was prepared by an initial synthesis of RGO-Bi₂O₃ (RGB) via a hydrothermal method. This was followed by the fabrication of conductive ink through homogenous mixing of the binary nanocomposite with CNTs in a mixture of ethanol, ethylene glycol, glycerol, and double-distilled water as the solvent. Electronic circuits were fabricated through directly writing the prepared ink on flexible nanocrystalline cellulose (NCC) thin film substrates. The nanocomposites consisted of rod-shaped nanoparticles that were grown on the surface of the nanographene sheet. The semiconductor nanocomposite exhibited excellent conductivity and further confirmed by applying it as an electrode in the electrical circuit to light a light-emitting diode (LED) bulb. The highest electrical conductivity achieved was 2.84 × 10³ S·m⁻¹ with a contact angle of 37°. The electronic circuit written using the conductive ink exhibited good homogeneity, uniformity, and adhesion. The LED experiment demonstrates the good conductivity of the electroconductive circuit and prepared ink. Hence, the NCC substrate and RGBC conductive ink showcase an excellent potential for flexible electronic applications.