Enhancement of dielectric response with PbS quantum dots doped nematic liquid crystals

Aydin D. B., El Abboubi M., Toprakoğlu M. K., CANDAN İ., Aydin G., Demir A., ...Daha Fazla

Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers, cilt.65, sa.12, 2026 (SCI-Expanded, Scopus)

Özet

The dielectric response of nematic liquid crystals (NLCs) can be modified by incorporating semiconductor nanostructures, particularly at low frequencies dominated by polarization and relaxation processes. In this work, we investigate the effect of lead sulfide quantum dots (PbS QDs) on the dielectric and optical properties of the NLC 4-cyano-4′-pentylbiphenyl (5CB) by preparing PbS–5CB composites (10 wt%). Broadband dielectric spectroscopy, capacitance–voltage measurements, current–voltage analysis, and UV–Vis transmission spectroscopy were employed to study electrical and optical characteristics. PbS QD incorporation enhanced the low-frequency real dielectric permittivity and increased dielectric loss due to Maxwell–Wagner–Sillars interfacial polarization and charge accumulation. The doped system exhibited non-Debye relaxation behavior and improved dielectric stability under DC bias. Optical measurements show reduced transmission due to PbS QD absorption, demonstrating tunable dielectric and optical properties in PbS–NLC composites.