Synthesis, Evolution of Morphology, Transport Properties for Bi2Te3 Nanoplates

Abstract

Bi2Te3 has an extensive application as thermoelectric materials. Here, large scale Bi2Te3 single-crystal hexagonal nanoplates(NPs) with size of 0.4–0.8 μm were synthesized successfully by hydro-thermal method. X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize the Bi2Te3 nanoplates, which confirm the single crystal quality and smooth surface morphology with large size. We discussed the morphology-evolution in detail the influence of various reaction factors which including: the reaction temperature, the reaction time, the surfactants of the polyvinyl pyrrolidone (PVP) and pH value. The synthesis method is not only green, but also shortens the reaction time and improves the reaction efficiency. The Bi2Te3 nanopowders were hot-pressed into solid state pellets through spark plasma sintering (SPS). The values of the electrical conductivity σ were about 0.16 × 10−5 Sm−1 and 0.22 × 10−5 Sm−1 at room temperature and 530 K, respectively. The values of the Seebeck coefficient S were around −81 μVK−1 and −118 μVK−1 at room temperature and 530 K, respectively.

Green Synthesis and Morphological Evolution for Bi2Te3 Nanosystems via a PVP-Assisted Hydrothermal Method

“…The Bi 2 Te 3 rhombic lattice is represented by all diffraction peaks in the XRD data (JCPDS: 15-0863). The stylized peaks are readily correlated with the planes of the Bi 2 Te 3 rhombic lattice phases (015), (1,0,10), ( 110), ( 205), (0,2,10), and (1,1,15) [12,[19][20][21][22]26,50,[59][60][61][62][63][64].…”

“…Recent research has shown that ZT of thermoelectric materials typically stays around 1.0 [14][15][16][17][18][19][20]. The conversion efficiency of Bi 2 Te 3 is low, but low power applications are gradually gaining the attention of researchers [21][22][23][24][25][26][27][28]. Currently, a wide range of demands have been developed for low-power generation and cooling technologies, the applications of which primarily operate in room-or low-temperature environments, such as micro-motor power systems, IoT wireless sensing modules, and wearable intelligent samples [29][30][31][32][33][34][35][36][37].…”

“…To date, a hydrothermal method has been proven to be a feasible method to change the morphology and size of the synthesized Bi 2 Te 3 nanostructures with low equipment and operating requirements, low cost, and low synthesis temperatures. Considerable effort has shown the synthesis of Bi 2 Te 3 , Bi 2 Se 3 , Sb 2 Te 3 , BiTe, and PbTe nanomaterials by using a solvothermal method [13,[19][20][21][22][23][24][25][26][34][35][36][61][62][63][64]. Some studies reported the effect of the morphology of the products, but the synthesis method was not "green", and some reported that the synthetic method was "green," but the morphological changes were not reported.…”

“…Other studies also reported that the synthesis method was "green" and tackled morphological changes, but the reaction efficiency was low [43][44][45][48][49][50][51]. However, a few papers on the impact of all response variables on morphology are found [19][20][21]26].…”

Bi2Te3 Thin Films Deposited by the Combination of Bi and Te Plasmas in a PLD Process

“…Concerning the Bi 2 Te 3 synthesis methods, the material was prepared successfully using techniques based on chemical reaction in solution, such as electroless deposition [ 6 ], electrochemical deposition [ 7 ], solvothermal [ 1 ], and sol–gel [ 8 ], among others. Such techniques require additional treatments to obtain a uniform and adherent thin film, free of secondary phases formed by the employed chemical precursors.…”