Systematic Investigation of Structural, Morphological, Thermal, Optoelectronic, and Magnetic Properties of High-Purity Hematite/Magnetite Nanoparticles for Optoelectronics

Abstract

Iron oxide nanoparticles, especially hematite (α-Fe2O3) and magnetite (Fe3O4) have attained substantial research interest in various applications of green and sustainable energy harnessing owing to their exceptional opto-magneto-electrical characteristics and non-toxicity. In this study, we synthesized high-purity hematite and magnetite nanoparticles from a facile top-down approach by employing a high-energy ball mill followed by ultrasonication. A systematic investigation was then carried out to explore the structural, morphological, thermal, optoelectrical, and magnetic properties of the synthesized samples. The experimental results from scanning electron microscopy and X-ray diffraction corroborated the formation of highly crystalline hematite and magnetite nanoparticles with average sizes of ~80 nm and ~50 nm, respectively. Thermogravimetric analysis revealed remarkable results on the thermal stability of the newly synthesized samples. The optical studies confirmed the formation of a single-phase compound with the bandgaps dependent on the size of the nanoparticles. The electrochemical studies that utilized cyclic voltammetry and electrochemical impedance spectroscopy techniques verified these iron oxide nanoparticles as electroactive species which can enhance the charge transfer process with high mobility. The hysteresis curves of the samples revealed the paramagnetic behavior of the samples with high values of coercivity. Thus, these optimized materials can be recommended for use in future optoelectronic devices and can prove to be potential candidates in the advanced research of new optoelectronic materials for improved energy devices.

Citric acid concentration tune of structural and magnetic properties in hematite (α−Fe2O3) nanoparticles synthesized by sol−gel method

“…Abdulkadir et al [41] demonstrated that the hematite nanoparticles made using the sol-gel method had small magnetic saturation values at annealing temperature of 400 °C, 500 °C, and 600 °C, with values of 2.91 emu g −1 , 2.63 emu g −1 , and 1.53 emu g −1 , respectively. Research conducted by Qureshi et al [42] also produced a low magnetic saturation value of hematite with a value of 1.24 emu g −1 which indicates paramagnetic behavior. As a result of variations in citric acid concentration, the magnetization (Ms and Mr) in the study's results did not show any particular tendency The highest saturation magnetization was obtained at 44.88 emu g −1 when the precursor concentration was 0.3 M. This is related to the larger magneto-crystal anisotropy when the concentration of citric acid was 0.3 M.…”

Enhanced specific loss power of hematite–chitosan nanohybrid synthesized by hydrothermal method

“…The maximum magnetization at 300 K, M max,300 K = 1.98 emu g −1 , the coercivity H C,300K = 2777 Oersted and remanent magnetization M r,300K = 0.150 emu g −1 , which are smaller compared to the values at 4 K. Usually, the magnetic properties of a material depend on several factors, including crystal structure, particle size, and morphology, as well as the competition between magnetic and thermal energy. Previous research showed that hematite nanoparticles are likely to exhibit a wide range of magnetic characteristics between superparamagnetism, antiferromagnetism, and ferromagnetism, with the slight fluctuation in particle sizes [14,46,53,54]. Bødker et al [14] and Mørup et al [46] reported an elaborate illustration of the effect of particle size on the magnetic properties of hematite nanoparticles ( particle size around 16-17 nm) by the Mössbauer spectroscopy and magnetization studies.…”

“…Figure 2f shows the size distribution of nanoparticles in this study from TEM image. This wide distribution of particle size may contribute to the mixed ferrimagnetic and superparamagnetic contributions in the magnetic properties [53][54][55][56][57]. royalsocietypublishing.org/journal/rsos R. Soc.…”

Understanding Biomineralization Mechanisms to Produce Size-Controlled, Tailored Nanocrystals for Optoelectronic and Catalytic Applications: A Review

“…163 These magnetic properties may be especially useful for applications in alternative energy; however, there is a need for inexpensive, monodisperse particles which is not met with current popular synthesis techniques. 129,164 Iron oxide nanoparticles, specifically Fe 3 O 4 is colloquially known as magnetite, and has been shown to be produced in magnetotactic bacteria. 165 In magnetotactic bacteria, this synthesis is localized to special organelles known as magnetosomes.…”

“…Iron oxide, Fe 2 O 3 and Fe 3 O 4 , is known for being an exceptionally thermodynamically stable variety of MoNP while also displaying useful magnetic and catalytic properties . These magnetic properties may be especially useful for applications in alternative energy; however, there is a need for inexpensive, monodisperse particles which is not met with current popular synthesis techniques. , …”