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<p>This work investigates oxidation-related quenching of the photoluminescence intensity of porous silicon produced from metallurgical-grade silicon powders, aiming to understand the mechanisms in this defect-rich material. The synthesis of porous silicon was performed by stain etching, but no catalyst was needed. It takes advantage of the inherent metallic impurities present in metallurgical-grade silicon to act as catalysts. The method is both scalable and cost-effective. By scanning electron microscopy, it was observed that etching created a porous layer on the surface of silicon grains, increasing the material's surface area by 200 times, as confirmed by BET adsorption isotherms. The photoluminescence spectra can be deconvoluted in three bands, which can be assigned to three main phenomena contributing to the emission: quantum confinement effects, oxidized silicon nanocrystals, and the presence of Si–H bonds. It has been found that the intensity of the photoluminescence spectrum decreases in proportion to the oxidation times of the porous silicon powders in hydrogen peroxide. They could be due to changes in the surface chemistry, replacing Si–H and Si–Si bonds with Si–OH and Si–O-Si bonds, as evidenced by Infrared spectroscopy ATR. The decay has been modeled mathematically, describing a first-order chemical reaction. The resulting equation could be used as a calibration curve to determine the amount of oxidant present in a solution if put in contact with the porous silicon. The results demonstrate the potential of photoluminescent porous silicon as a base material for developing low-cost optoelectronic devices and chemical sensors.</p> Graphical Abstract <p>Porous silicon powders synthesized from metallurgical grade silicon by stain etching present intense photoluminescence of about 685&#xa0;nm. The total photoluminescence intensity decreases with chemical oxidation due to the competing effects of non-radiative Si–OH and radiative Si–O-Si. The present study provides valuable insights into the photoluminescent mechanisms of metallurgical-grade porous silicon.</p> <p></p>

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Quenching of Photoluminescence of Metallurgical Grade Porous Silicon By Chemical Oxidation

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  • 发表日期：

    2025年10月23日

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  • Xairo León-Valiente,
  • César Márquez-Beltrán,
  • Enrique Quiroga-González

摘要

This work investigates oxidation-related quenching of the photoluminescence intensity of porous silicon produced from metallurgical-grade silicon powders, aiming to understand the mechanisms in this defect-rich material. The synthesis of porous silicon was performed by stain etching, but no catalyst was needed. It takes advantage of the inherent metallic impurities present in metallurgical-grade silicon to act as catalysts. The method is both scalable and cost-effective. By scanning electron microscopy, it was observed that etching created a porous layer on the surface of silicon grains, increasing the material's surface area by 200 times, as confirmed by BET adsorption isotherms. The photoluminescence spectra can be deconvoluted in three bands, which can be assigned to three main phenomena contributing to the emission: quantum confinement effects, oxidized silicon nanocrystals, and the presence of Si–H bonds. It has been found that the intensity of the photoluminescence spectrum decreases in proportion to the oxidation times of the porous silicon powders in hydrogen peroxide. They could be due to changes in the surface chemistry, replacing Si–H and Si–Si bonds with Si–OH and Si–O-Si bonds, as evidenced by Infrared spectroscopy ATR. The decay has been modeled mathematically, describing a first-order chemical reaction. The resulting equation could be used as a calibration curve to determine the amount of oxidant present in a solution if put in contact with the porous silicon. The results demonstrate the potential of photoluminescent porous silicon as a base material for developing low-cost optoelectronic devices and chemical sensors.

Graphical Abstract

Porous silicon powders synthesized from metallurgical grade silicon by stain etching present intense photoluminescence of about 685 nm. The total photoluminescence intensity decreases with chemical oxidation due to the competing effects of non-radiative Si–OH and radiative Si–O-Si. The present study provides valuable insights into the photoluminescent mechanisms of metallurgical-grade porous silicon.