Influence of morphology, crystal structures on the enhanced photoluminescence dynamics, zeta potential, and AC resistance of disc shaped cesium oxidex@cobalt oxide nanostructures

• A novel series of Cs 2 O x @Co 3 O 4 (x = 5, 10 and 12 wt%) bimetallic oxide NS were synthesized. • Disc shaped morphology was formed upon doping Cs 2 O on Co 3 O 4 NS with decrease in optical band gap. • RTPL and SSPL showed sharp and broad emission intensity peaks and are redshifted. • Zeta potential varies between 37.90 to 82.92 mV with decrease in polydispersity and NS is cationic. • AC resistance at various temperatures showed Cs 2 O 12 wt% @Co 3 O 4 NS has more ionic in nature. • I-V nature become purely blocking and non-linear with increase in Cs 2 O concentration on Co 3 O 4 NS. In the present study, cesium oxide x @cobalt oxide (Cs 2 O x @Co 3 O 4 ) (x = 5, 10 and 12 wt%) nanostructures (NS) were successfully synthesized by chemical precipitation method and characterized by XRD (X-ray diffraction), SEM (scanning electron microscope), EDX (energy dispersive X-ray), XPS (X-ray photoelectron spectroscopy), BET (Brunauer-Emmett-Teller), Raman, and UV–visible analytical techniques. XRD studies revealed the formation of the mixed phase of orthorhombic/monoclinic crystal structure. Disc shaped morphology of the cesium oxide x @cobalt oxide NS was noticed from SEM images. Redshift in optical absorbance and decrease in optical band gap (E g ) resulted in increase in Cs 1+ concentration. Room temperature photoluminescence (RTPL) studies of cesium oxide x @cobalt oxide NS at various excitation wavelengths showed sharp and broad emission peaks located at 668.2 nm (red), 675.1 nm (red), 561.8 nm (yellow-green), 834.5 nm (near infrared region), 594 nm (yellow). Steady state photoluminescence (SSPL) studies revealed a sharp emission peak at ∼ 428.0 nm (violet) with large stoke’s shift (21.1 to 590.0 eV). The zeta potential studies showed a decrease in conductance from 62 to 57 μs with an increase in mobility of the charge carriers (0.4 to 1.08 μ/s V/cm) and an increase in zeta potential (31.90 to 82.92 mV). AC resistance studies at various temperatures showed inducting coupling phenomenon in cesium oxide x @cobalt oxide NS with DC resistance of cesium oxide 5 wt.% @cobalt oxide was found to be 8.2 × 10 –4 Sm –1 . The relaxation frequency of cesium oxide 12 wt.% @cobalt oxide NS was found be 1.2 × 10 5 Hz. The synthesized NS is a promising candidate for optoelectronics and photonic applications.