Composites of Te nanorods and TeO₂ nanoparticles: chemical synthesis in an alkaline condition, characterization and photovoltaic measurements

Composites of Te nanorods and TeO₂ nanoparticles have been successfully synthesized via a reduction chemical method in an alkaline condition. In this method, TeCl₄ and N₂H₄·H₂O used as starting materials were heated at 70 °C for 10 min in the presence of NaOH solution. To study the effect of NaOH on the formation mechanism of the products, the experiment marked as blank test was carried out without using NaOH solution. X-ray powder diffraction (XRD) analysis of the product obtained from the blank test showed that Te nanorods could be only formed by using TeCl₄ and N₂H₄·H₂O in the absence of NaOH at the same conditions. In addition, the effect of NaOH concentration on the morphology and chemical composition of the composites was investigated. Based on the XRD results, it was found that the production of the TeO₂ nanoparticles increased by increasing the concentration of NaOH solution. Besides, the electron microscopy images of the products indicated that the lengths of the Te nanorods increased by increasing the concentration of NaOH solution. The final products have been characterized by XRD, SEM and TEM. We have also studied the photocurrent density–voltage (J–V) curve of the as-synthesized composites.