Size- and Shape-Controlled Synthesis of CdTe and PbTe Nanocrystals Using Tellurium Dioxide as the Tellurium Precursor

Abstract

We have developed a new method for the synthesis of CdTe and PbTe nanocrystals by using TeO2 with trioctylphosphine oxide as Te precursor. Using this method, uniform-sized CdTe nanocrystals are successfully synthesized without the use of any air-sensitive alkylphosphine. The monodispersity, size, and shape of as-synthesized CdTe nanocrystals are well-controlled using “green” chemicals at elevated temperatures; the photoluminescence emission of CdTe nanocrystals covers a wide range from 510 to 750 nm. Oleic acid has been chosen as the only ligand to achieve controllable synthesis of CdTe nanocrystals with not only different sizes covering from green to red emissions but also different crystal structures (wurtzite and zinc blende) and shapes (including spherical, tetrapod, dendrimer, and flower) by simply adjusting the injection and/or growth temperatures. PbTe nanocrystals with spherical and cubic shapes have also been synthesized successfully with this new tellurium precursor and they can easily self-assemble into two-dimensional ordered structures. Special attention has also been paid to the studies of the new molecular mechanisms involved in the formation of metal telluride nanocrystals.

One-pot synthesis of high quality CdE (E = Te, TexSe1−x, Se) nanocrystals without using pyrophoric reagents

“…We described a mechanism that Te-di-n-octylphosphinic acid (Te-DOPA) complex was formed in the Te-containing reaction mixture upon reaction with TOPO (90%) at high temperature [34]. Different from previous reports [29,31,33], in our experiments, Se powder was directly added into the reaction solution since it could react with paraffin oil to form the complex and reacted with Cd species.…”

Shape-Programmed Nanofabrication: Understanding the Reactivity of Dichalcogenide Precursors

“…Experimentally, we observe that differently substituted dichalcogenides lead to completely different nanocrystal morphologies, some lead to dots, others to rods or tetrapods. The selectivity for such anisotropic structures is obviously affected by reaction parameters such as reaction time 17 and temperature, 18,19 precursor concentration, 20 medium acidity, 21 ligand type (amines, 22À24 halides, 52 phosphonic acids 25,26 ) and chain length. 27,28 Commonly used methods to obtain IIÀVI and IVÀVI rods and tetrapods include seeded growth, 29À32 continuous precursor injection, 33,34 and noninjection routes.…”

Synthesis, characterization and photocatalytic performance of Yb-doped CdTe nanoparticles

“…It can be explained that the ionic radius of Yb þ 3 (100.8 nm) is smaller than Cd þ 2 ion (109 nm). Beyond doping levels of x¼ 0.1, the intensity of some CdTe peaks decreased and additional impurity phase related to Te and Yb 2 O 3 were observed (see Supporting information) [11,12].…”