Solution-Based Synthesis of GeTe Octahedra at Low Temperature

Abstract

GeTe octahedra were prepared by reaction of equimolar amounts of GeCl 2 ·dioxane and Te(SiEt 3 ) 2 in oleylamine, whereas a slight excess of the Te precursor yielded GeTe octahedra decorated with elemental Te nanowires, which can be removed by washing with TOP. The mechanism of the GeTe formation is strongly influenced by the solvent. The expected elimination of Et 3 SiCl (dehalosilylation) only occurred in aprotic solvents, whereas Te(SiEt 3 ) 2 was found to react with primary and secondary amines with formation of silylamines. Temperature-dependent studies on the reaction in oleylamine showed that crystalline GeTe particles are formed at temperatures higher than 140 °C. XRD, SAED, and HRTEM studies proved the formation of rhombohedral GeTe nanoparticles. These findings were confirmed by a single-crystal and powder X-ray analysis. The rhombohedral structure modification was found, and the structure was solved in the acentric space group R3m. Disciplines Ceramic Materials | Complex Fluids | Other Materials Science and Engineering | Thermodynamics CommentsReprinted with permission from Inorg. Chem., 2013, 52 (24) ABSTRACT: GeTe octahedra were prepared by reaction of equimolar amounts of GeCl 2 · dioxane and Te(SiEt 3 ) 2 in oleylamine, whereas a slight excess of the Te precursor yielded GeTe octahedra decorated with elemental Te nanowires, which can be removed by washing with TOP. The mechanism of the GeTe formation is strongly influenced by the solvent. The expected elimination of Et 3 SiCl (dehalosilylation) only occurred in aprotic solvents, whereas Te(SiEt 3 ) 2 was found to react with primary and secondary amines with formation of silylamines. Temperature-dependent studies on the reaction in oleylamine showed that crystalline GeTe particles are formed at temperatures higher than 140°C. XRD, SAED, and HRTEM studies proved the formation of rhombohedral GeTe nanoparticles. These findings were confirmed by a single-crystal and powder X-ray analysis. The rhombohedral structure modification was found, and the structure was solved in the acentric space group R3m.

Intramolecularly-stabilized Group 14 Alkoxides - Promising Precursors for the Synthesis of Group 14-Chalcogenides by Hot-Injection Method

“…Figure exemplarily shows the PXRDs of the GeTe, SnSe, SnTe, and PbTe powders, while those of the remaining chalcogenide materials are given in Figures S7, S11, S16, S20 and S22 (Supporting Information). The PXRD of GeTe showed additional reflections due to elemental Te as was previously observed …”

“…We are generally interested in the development of new (metal organic) precursors for the solution‐based synthesis of group 14 chalcogenide nanoparticles as well as the deposition of thin films by gas‐phase based processes such as chemical vapor deposition (CVD) or atomic layer deposition (ALD). Recently, we reported on the synthesis of highly stoichiometric, crystalline GeTe nanoparticles by reaction of GeCl 2 (dioxane) with Te(SiEt 3 ) 2 . Unfortunately, the low vapor pressure of GeCl 2 (dioxane) hampers its use as precursor in gas‐phase based processes, which is also true for crystalline single source precursors such as [(Me 3 Si) 2 N] 2 Ge( ER ) 2 ( E = S, Se, Te), Me 2 Si(N t Bu) 2 Ge( ER ) 2 ( E = S, Se), and [(Me 3 Si) 2 N] 2 Sn( ER ) 2 ( E = S, Se, Te), which have been recently applied in the wet chemical synthesis of group 14 chalcogenides .…”

Wet-chemical synthesis of different bismuth telluride nanoparticles using metal organic precursors – single source vs. dual source approach

“…Even though TOPTe is a suitable Te-precursor for the solutionbased synthesis of bismuth tellurides, alternative Te-precursors have been investigated. A promising candidate is bis(triethylsilyl)tellurane (Et 3 Si) 2 Te, whose general capability to serve as rather low-temperature Te-precursor for the deposition of Sb 2 Te 3 and Bi 2 Te 3 thin films by atomic layer deposition (ALD) [8] as well as for the wet-chemical synthesis of GeTe-nanoparticles [9] was recently demonstrated. In addition, bis(trimethylsilyl)tellurane (Me 3 Si) 2 Te in combination with bismuth trisamides Bi(NR 2 ) 3 was also successfully applied as low-temperature MOCVD precursor for the deposition of Bi 2 Te 3 thin films.…”

Synthesis of Bi2Te3and (BixSb1−x)2Te3nanoparticles using the novel IL [C4mim]3[Bi3I12]

“…In contrast, thermolysis of (Et 3 Si) 2 Te and [C 4 mim] 3 [Bi 3 I 12 ] in a solution of 10 mL [C 4 mim]I and 3 mL oleylamine (OA) at 150°C yielded pure Bi 2 Te 3 nanoparticles according to EDX studies (Scheme 2). We recently demonstrated that OA reacts with (Et 3 Si) 2 Te at ambient temperature with formation of silylamine (Et 3 SiOA) and tellurium polyanions,28 which then consequently react with [C 4 mim] 3 [Bi 3 I 12 ] with the formation of Bi 2 Te 3 .…”