Synthesis of Stoichiometric FeS₂ through Plasma-Assisted Sulfurization of Fe₂O₃ Nanorods

Abstract

Pyrite (FeS(2)) thin films were synthesized using a H(2)S plasma to sulfurize hematite (Fe(2)O(3)) nanorods deposited by chemical bath deposition. The high S activity within the plasma enabled a direct solid-state transformation between the two materials, bypassing S-deficient contaminant phases (Fe(1-x)S). The application of plasma dramatically enhanced both the rate of conversion and the quality of the resulting material; stoichiometric FeS(2) was obtained at a moderate temperature of 400 °C using a chalcogen partial pressure <6 × 10(-5) atm. As the S:Fe atomic ratio increased from 0 to 2.0, the apparent optical band gap dropped from 2.2 (hematite) to ~1 eV (pyrite), with completely converted layers exhibiting absorption coefficients >10(5) cm(-1) in the visible range. Room-temperature conductivity of FeS(2) films was on the order of 10(-4) S cm(-1) and approximately doubled under calibrated solar illumination.

Fabrication of a low-concentration H2S gas sensor using CuO nanorods decorated with Fe2O3 nanoparticles

“…As a result, in the case of the decorated nanorods, the resistance of the nanorod sensor dramatically changes on exposure to H 2 S gas. Furthermore, CuO and Fe 2 O 3 are well-known H 2 S-sensing materials, their utility deriving from the catalytic effects of adsorption of H 2 S gas [26,27]. As more H 2 S is adsorbed at the sensor surface, the number of reacting oxygen ions and H 2 S molecules increases, resulting in a synergistic H 2 S gas sensing effect and increasing both the response and selectivity of the sensor for H 2 S at low concentrations.…”

Morphology controllable syntheses of micro- and nano-iron pyrite mono- and poly-crystals: a review

“…The sputtering deposition, [125][126][127][128][129] microwave, [130][131][132] plasma, 91,124 magnetic eld, 133 electrochemical deposition, 134 pulsed electron ablation 135 and mechanical milling 136 were employed to synthesize iron pyrite. However, not all of these highly efficient methods could be the appropriate ones to synthesize iron pyrite crystals with the designed morphologies.…”

Scientific and Technological Assessment of Iron Pyrite for Use in Solar Devices

“…[22] Attempts to study these fundamental factorstou nderstand the problem of low output photovoltage,a nd above-mentioned issues,h ave led to the utilization of severals ynthesis and processing schemes,w hich have resulted in numerous types of thin films and nanostructures in iron pyrite. [11,[23][24][25][26][27][28][29][30] Early attempts by Tr ibutsch and wo-workerst op repare iron pyrite-sensitized TiO 2 solar cells showedh igh externalq uantum efficiency( up to % 90 %), but the overall efficiency remained low because of limited photovoltage. [31,32] Recent studies on similar device structures also validate these findings.…”