研究目的
To study the structural and electrical properties of the prepared PbS and PbTe nanomaterials since their large surface-to-volume ratios have deep effects on most chemical and physical properties.
研究成果
PbS and PbTe nanomaterials were successfully synthesized with polycrystalline structures. PbTe exhibited higher dielectric constant and conductivity compared to PbS, attributed to smaller crystallite size. The conduction mechanism follows the correlated barrier hopping model, and non-Debye relaxation is observed.
研究不足
The study is limited to PbS and PbTe nanomaterials synthesized via hydrothermal method; other synthesis methods or materials are not explored. Measurements are constrained to frequencies up to 1 MHz and temperatures up to 423 K. Potential errors in permittivity (1%) and dielectric losses (3%) are noted.
1：Experimental Design and Method Selection:
PbS and PbTe nanomaterials were synthesized using a hydrothermal method. Structural analysis was performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with EDX analysis. Dielectric properties were measured using an impedance analyzer over a frequency range of
2：1 Hz to 1 MHz and temperatures from 298 to 423 K. Sample Selection and Data Sources:
Samples were prepared from starting materials including polyethylene glycol, sodium hydroxide, sodium tellurite, sodium sulfite, lead acetate trihydrate, hydrazine hydrate, and thiourea.
3：List of Experimental Equipment and Materials:
Equipment includes a scanning electron microscope (QuantaFEG 250), X-ray diffractometer (Bruker D8), impedance analyzer (Solartron 1260-Schlumberger Ltd. UK), temperature regulator with Pt 100 sensor, and materials such as PEG, NaOH, NaTeO3, NaSO3, PbAc, hydrazine hydrate, thiourea.
4：Experimental Procedures and Operational Workflow:
For PbTe, PEG and NaOH were added to de-ionized water, followed by NaTeO3 and PbAc, then hydrazine hydrate, and heated in an autoclave at 170 °C for 10 h. For PbS, Pb(Ac)2·3H2O and thiourea were added to water, heated in an autoclave at 170 °C for 12 h. Products were washed, dried, and characterized. Dielectric measurements were automated using LabVIEW software.
5：Data Analysis Methods:
XRD data analyzed for crystallite size, lattice parameters, strain, and dislocation density. Dielectric data analyzed using electric modulus formalism and Jonscher's power law for AC conductivity.
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