Synthesis, mechanism, optical and electrical characterization of PbTe micro-needles

The face-centered cubic PbTe micro-needles were synthesized by a simple aqueous chemical reaction between lead acetate and tellurium in NaOH solution in the presence of Na2HPO4 as reducing reagent at low temperature under atmospheric pressure without any additional surfactants or templates. Micro structural analyses show that these micro-needles are in the range of 90–130 nm in diameter with length ∼2 μm. Electrical resistivity of prepared PbTe micro-needles was found to be 14–33 Ohm-cm. The optical absorption spectrum of PbTe micro-needles shows large blue-shift (∼1.26 eV) with respect to those of the bulk counterpart (0.32 eV) due to quantum confinement of charge carriers, which is consistent with the blue shift of the band emission peak in the photoluminescence spectrum.

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► PbTe nanoneedles were prepared at low temperature without any surfactant or template.
► The synthetic method is very simple, economical and environment benign.
► PbTe nanoneedles exhibit low resistivity, which improves thermoelectric performance.
► PbTe nanoneedles show large blue-shift due to quantum confinement effect.