Microwave-assisted synthesis of Cu doped PbS nanostructures with enhanced dielectric and electrical properties for optoelectronic applications

Highlights: • Rapid synthesis of pure and Cu doped PbS NPs was achieved by microwave route. • Monophasic synthesis was confirmed by XRD, Raman, EDX/SEM mapping. • FESEM analysis revealed homogeneous low dimension NPs synthesis of Cu:PbS. • Dielectric constant values are noticed between 26 and 49 for Cu:PbS NPs. • Electrical conductivity was calculated between 1.17 and 7.60 (×10⁻⁶) (ohm/cm)⁻¹ for Cu:PbS NPs. Herein, facile CTAB surfactant-assisted synthesis of Pb_1-xCu_xS (x = 0, 0.1, 0.5, 1.0, 2.5 & 5.0 wt%) nanostructures (NSs) via a microwave route within 10 mins was attained and investigated for their structural, optical, vibrational, dielectric and electrical properties using X-ray diffraction, FT-Raman, UV–VIS, impedance and I-V measurements. Structural study with Rietveld refinement confirms the synthesis of PbS predominantly with cubic phase; however, at higher content of Cu some CuS peaks are detected. The values crystallite size of all Pb_1-xCu_xS specimens were determined between 19 and 25 nm and the specific surface area between 31 and 40 m²/g. Vibrational modes are noticed at 59.59, 74.05, 127.04, 268.82, 426.96, 601.49 cm⁻¹ in all specimens confirmed cubic PbS NSs synthesis. As received powders were tested through DRS to evaluate the energy gap values via Kubelka-Munk model and noticed between 1.02 ± 0.01 to 1.37 ± 0.01 eV tuned with crystallite size. Dielectric studies reveal that the Cu doping enhanced the capacitance/dielectric constant and ac electrical conductivity of PbS NSs. Moreover, the I-V nature of the prepared Pb_1-xCu_xS NSs was measured, and dc conductivity was calculated and noticed to be enriched with Cu doping. The enhanced dielectric and electrical properties make the prepared materials useful for optoelectronic devices.