Colloidal Synthesis and Thermoelectric Properties of CuFeSe2 Nanocrystals

Abstract

Copper-based chalcogenides that contain abundant, low-cost and environmentally-friendly elements, are excellent materials for numerous energy conversion applications, such as photocatalysis, photovoltaics, photoelectricity and thermoelectrics (TE). Here, we present a high-yield and upscalable colloidal synthesis route for the production of monodisperse ternary I-III-VI2 chalcogenides nanocrystals (NCs), particularly stannite CuFeSe2, with uniform shape and narrow size distributions by using selenium powder as the anion precursor and CuCl2·2H2O and FeCl3 as the cationic precursors. The composition, the state of valence, size and morphology of the CuFeSe2 materials were examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM), respectively. Furthermore, the TE properties characterization of these dense nanomaterials compacted from monodisperse CuFeSe2 NCs by hot press at 623 K were preliminarily studied after ligand removal by means of hydrazine and hexane solution. The TE performances of the sintered CuFeSe2 pellets were characterized in the temperature range from room temperature to 653 K. Finally, the dimensionless TE figure of merit (ZT) of this Earth-abundant and intrinsic p-type CuFeSe2 NCs is significantly increased to 0.22 at 653 K in this work, which is demonstrated to show a promising TE materialand makes it a possible p-type candidate for medium-temperature TE applications.

Stable Photodetectors Based on Formamidinium Lead Iodide Quantum Well Perovskite Nanoparticles Fabricated with Excess Organic Cations

“…FTIR spectra of OA and OAm indicate the characteristic peaks of the CO bond (carboxyl group) of OA and N–H (amine group) bond of OAm at 1710 and 3325 cm –1 , respectively (Figure d) . These characteristic peaks are not visible in the spectrum of FAPbI 3 CQDs.…”

“…The results indicate the successful roomtemperature synthesis and stabilization of the α-phase perovskite as a consequence of decreasing the phase trans- 1d). 51 These characteristic peaks are not visible in the spectrum of FAPbI 3 CQDs. Elimination of these peaks can be attributed to the decrease in chain movement due to the interactions between QD surface atoms and ligands.…”

Ultrafine Interwoven Dendritic Cu2Se/CuFeSe2 Composites with Enhanced Thermoelectric Performance

“…Here, we show that one elegant approach to achieve this objective is to exploit the temperature-dependent phase solubility between Cu 2 Se and CuFeSe 2 phases to create composites with the complex microstructure, while enabling simultaneously temperature-dependent doping of the matrix. CuFeSe 2 is reported to be a p-type semimetallic compound with paramagnetic behavior at room temperature. − In this study, we design and synthesize the composite materials (1 – x )­Cu 2 Se/( x )­CuFeSe 2 with x = 0, 0.005, 0.01, 0.02, 0.03, 0.05, and 0.10. We find that Fe has such a limited solution limit ( x < 0.02) in the Cu 2 Se structure at room temperature, leading to the formation of CuFeSe 2 precipitates for compositions with x ≥ 0.02.…”

Sub-10 nm Cu₅FeS₄ cube for magnetic resonance imaging-guided photothermal therapy of cancer

“…[33][34][35] In addition, there are many kinds of ternary composites based on copper sulfide (eg, Cu 5 FeS 4 ), and the preparation method is also simple. [36][37][38] Therefore, it is facile to design and synthesize T 1 -weighted MRI-guided PTT agents based on ternary composites of copper sulfide. [39][40][41] Herein, a Cu 5 FeS 4 cube with a diameter of ~5 nm was prepared by a simple one-pot pyrolysis of the mixture of iron acetylacetonate and copper acetylacetonate.…”