Luminous Intensity Research Articles

Enhancing light out-coupling in flexible organic light emitting devices through the localized surface plasmon resonance of urchin-like gold nanoparticles

The local surface plasmon resonance (LSPR) effect and scattering properties of gold nanoparticles are effective ways to improve the light extraction efficiency of organic light-emitting diodes (OLEDs). Here five different kinds of urchin-like gold nanoparticles (UGNs) were synthesized using the seed-mediated method. The finite-difference time-domain (FDTD) method was used to calculate the near-field local and far-field scattering properties of various sea urchin-like gold nanoparticles. All five types of UGNs demonstrated certain levels of light enhancement within the visible band. The flexible OLED devices were created by doping five different types of nanoparticles into the flexible substrates. The hollow UGNs device exhibited a maximum current efficiency of 124.25 cd/A, a maximum power efficiency of 131.27 lm/W, and a maximum EQE of 45.54 %. When compared to undoped flexible devices, the maximum current efficiency, the maximum power efficiency, and the maximum EQE increase by 132 %, 82 %, and 36%, respectively. The results indicate that combining the flexible conductive substrate and UGNs is an effective strategy for improving light extraction from flexible OLEDs. This enhancement effect originates from UGNs acting as a scattering layer to reduce total light reflection, and the luminous intensity of the device is improved due to the LSPR of sea urchin-like nanoparticles.

Metrology and economics: on the choice of the best options for the development of metrology systems by the criterion of minimum necessary costs – a review

A general approach to substantiating the best ways to develop national metrology systems based on minimizing the financial investments needed is formulated. The methods that have been developed at the NSC “Institute of Metrology” for estimating the effectiveness of investments for different possible options of functionality of metrological infrastructure elements related to certain types of measurements are analysed. In particular, the following options have been considered: a state primary (national) measurement standard of a unit that has passed international comparisons; there is no primary measurement standard yet, but it is being developed; there is no primary measurement standard yet and it is not being developed; a calibrated abroad secondary measurement standard used as a reference standard in the absence of a primary one. The paper presents mathematical algorithms for analysing the economic feasibility of investments, which allow choosing the least costly solutions. An approach to calculating the payback period of the investments that takes into account inflationary processes is proposed. Examples of application of the developed algorithms to analyse the economic feasibility to establish measurement standards, specifically, state primary measurement standards of the unit of volume activity of radon-222 and luminous intensity, are given. The algorithms presented in the paper for selecting the best options for the development of metrology system and increasing the efficiency of investments in metrology are especially relevant for countries with limited financial resources.

Study of lighting characteristics of LED analogues of domestically produced linear fluorescent lamps

LED linear lamps are gaining popularity in various fields of application due to their advantages in energy efficiency, durability and lighting quality. The paper considers the designs of the tested LED lamps of domestic production by AVANLED company intended to replace fluorescent lamps T8 with a power of 18 W, and also studies their lighting characteristics. Structurally, the studied lamps are produced in two versions: with a transparent and frosted glass bulb. Analysis of the dependence of the electrical characteristics of the lamps on the network voltage (Uc) has proved that they are practically independent of changes in Uc within ± 15 %. The results of measurements of lighting characteristics have shown that most parameters correspond to the declared values: the error of color temperature does not exceed 5 %, the error of color rendering index is 0.1 %, and the pulsation index of luminous flux is within the declared 5 % and equals 0.1 %. The luminous flux at the nominal voltage of the network differs from the declared value of 1,000 lm, and the luminous flux of LED lamps with a transparent tube is less than with a matte one. The power of the lamps varies from 8 to 8.7 W, which does not correspond to the declared 9 W. The luminous efficiency of LED lamps with a color temperature of 6,500 K corresponds to the declared value. For LED lamps with a color temperature of 4,000 K (matte bulb), the luminous efficiency is 2.4 % higher than the declared value. The luminous efficiency of the remaining lamps is less than the declared value. Analysis of the spatial distribution of luminous intensity has shown that LED lamps with a frosted glass bulb are suitable for replacing fluorescent lamps in luminaires with mirror optics, and LED lamps with a transparent glass bulb are suitable for replacing fluorescent lamps in luminaires with a diffuser reducing the glare of LEDs.

Orthogonal‐Based Reconfigurable Light‐Controlled Metasurface for Multichannel Amplitude‐Modulation Communication

AbstractOptical‐control reconfigurable metasurfaces can avoid crosstalk between microwave signal and direct current (DC) signal caused by physical wire connection, which paves a paradigm for dynamically and remotely controlling electromagnetic (EM) wave. However, the traditional light‐controlled reconfigurable metasurfaces mainly focus on the modulation of single polarized EM wave, which is difficult to adapt to the modulation of various signals in communication. In this work, a photoresistor is fully embedded into the meta‐atom as an active device, and a light‐controlled reconfigurable metasurface (LCRM) with multi‐polarization amplitude modulations is proposed. The designed metasurface controls the luminous intensity of light emitting diode (LED) array through computer, and then adjusts the photoresistor value, which can achieve amplitude modulations. In order to verify the feasibility and effectiveness of the proposed framework, the metasurface is simulated, fabricated, and measured, and the measurement results are basically consistent with the theoretical simulation results. Based on the EM characteristics of the designed metasurface, linear polarized (LP) wave synthesis and information transmission are carried out to demonstrate the design. This work designs an amplitude modulation metasurface under orthogonal‐polarization wave incidence to expand the LCRM application, which has broad development prospects in many fields such as information transmission, communication systems, and holographic imaging.

Optical Centers in Cr-, Mn-, and O-Doped AlN and Their Thermodynamic Stability Designed by a Multiscale Computational Approach.

The optical centers in AlN can frequently exist in various charge states and can be accompanied by many coexisting defect species, creating a complex environment where mutual interactions are inevitable. Therefore, it is an immediate quest to design AlN crystal growth protocols that can target a specific optical center of interest and tune its concentration while preventing the formation of other unwanted point defects. Here, we provide a powerful workflow for point defect engineering in wide band gap, binary semiconductors that can be readily used to design optimal crystal growth protocols through combining CALPHAD-based phase analysis, and ab initio defect calculations. We investigate technologically relevant chromium- and manganese-induced optical centers in AlN, followed by studying the impact of oxygen that can be unintentionally incorporated during crystal growth. We present the dominant defects in all three cases as a function of process parameters along with the optical signatures. In the case of both Cr and Mn doping, the CrAl and MnAl defects are most likely, and increasing nitrogen partial pressure tends to enhance their concentration. We show that it is possible to use nitrogen fugacity as a tool for tuning the intensity of optical signatures. We calculate the CrAl charge transition levels with respect to the valence-band maximum at 2.60 eV (E+/-), 3.83 eV (E0/-), and 5.41 eV (E-/2-) and electron and hole capture transitions with luminescence bands centered at 2.82, 1.91, and 3.15 eV. Unlike the Cr doping, Mn aggregation is unlikely, and the MnAl-VN is the most abundant defect after MnAl under most synthesis conditions. Oxygen tends to form complexes with VAl, and ON-VAl is a prominent defect following ON, with near-UV emission bands at 3.17, 3.26, and 3.81 eV. Our results agree with the available experimental optical signatures of Cr-, Mn-, and O-related centers and provide pathways on how to tune the luminous intensity of these centers through changes in growth conditions.

Visual research on spray and low temperature combustion of biodiesel/ethanol/water micro-emulsified fuels

To solve the negative environmental problems derived from the transport sector, this study is devoted to realizing a thorough substitution of biomass fuels for petroleum diesel. The spray, ignition, combustion, and emission of pure biodiesel, biodiesel/ethanol blend, and two kinds of biodiesel/ethanol/water triple micro-emulsified fuels were studied through optical visual methods on a constant volume combustion chamber. First of all, the micro-emulsified fuels obviously improve the spray quality. The micro-explosion effect of internal water improves the spray and atomization and the gas–liquid phase spray projected areas of microemulsion fuel at the maximum water blending ratio are the largest in the mid and late stages of spray. Secondly, with the increase of the water blending ratio, the combustion process of the fuel is improved. The flame lift-off length increases, the ignition delay period is prolonged, and the air entrainment effect is enhanced. Meanwhile, the combustion flame temperature decreases with the increase of water content, realizing low-temperature combustion. Lastly, the micro-emulsified fuels markedly decrease soot emissions. Both the total luminous intensities and normalized total KLs of micro-emulsified fuel with high water content are the lowest, achieving the best soot reduction effect. The triple micro-emulsified fuels have significant potential as a full biomass alternative fuel.

Interfacial functionalization and capillary force welding of enhanced silver nanowire-cellulose nanofiber composite electrodes for electroluminescent devices.

The development of flexible, intelligent, and lightweight optoelectronic devices based on flexible transparent conductive electrodes (FTCEs) utilizing silver nanowires (AgNWs) has garnered increasing attention. However, achieving low surface resistance, strong adhesion to the flexible substrate, low surface roughness, and green degradability remains a challenge. Here, a composite electrode combining natural polymer cellulose nanofibers (TCNFs) with AgNWs was prepared. This process includes non-covalent interface embedding between TCNFs and AgNWs as well as a strong capillary force between the hydrophilic TCNF substrate and AgNWs during water mist capillary force cold welding. By adding ethanolamine and employing a rapid water mist wetting-drying process (within 10 s), the performance of TCNF/AgNW FTCEs significantly improves with reduced sheet resistance (8.3 Ω sq.-1), high light transmission (84.9 %), and low surface roughness (9.9 nm). Additionally, the composite electrode exhibits excellent stability and durability under various conditions such as bending, adhesion, and tensile stress. The prepared flexible electroluminescent device achieves high luminous intensity (43.6 cd m-2) and excellent operational stability, thanks to the outstanding performance of the composite electrode. This study presents a simple strategy for fabricating FTCEs using nanocellulose combined with AgNWs offering a potential material option for key components in green flexible optoelectronic devices.

A Hybrid Photoplethysmography (PPG) Sensor System Design for Heart Rate Monitoring.

A photoplethysmography (PPG) sensor is a cost-effective and efficacious way of measuring health conditions such as heart rate, oxygen saturation, and respiration rate. In this work, we present a hybrid PPG sensor system working in a reflective mode with an optoelectronic module, i.e., the combination of an inorganic light-emitting diode (LED) and a circular-shaped organic photodetector (OPD) surrounding the LED for efficient light harvest followed by the proper driving circuit for accurate PPG signal acquisition. The performance of the hybrid sensor system was confirmed by the heart rate detection process from the PPG using fast Fourier transform analysis. The PPG signal obtained with a 50% LED duty cycle and 250 Hz sampling rate resulted in accurate heart rate monitoring with an acceptable range of error. The effects of the LED duty cycle and the LED luminous intensity were found to be crucial to the heart rate accuracy and to the power consumption, i.e., indispensable factors for the hybrid sensor.

Tuning the performances of smoke-light signaling agents by Zn-Mg alloys

In this study, the thermal behavior, combustion behavior, and smoke/light signal effects of smoke-light signaling agents were regulated using Zn-Mg alloys with different Mg contents (10 wt%, 20 wt%, 30 wt%, 50 wt%, 70 wt%) and particle sizes (100–200 mesh, 200–325 mesh, >325 mesh) under an oxygen balance of −20. The Zn-Mg alloy’s morphology and phase composition were characterized using SEM/EDS and XRD. The thermal performance was analyzed with TG/DSC, while the combustion process was recorded using high-speed camera and infrared thermal imaging. The visible light spectrophotometer and smoke chamber experiment tested the smoke and light effects. The results showed that increasing Mg content raised the combustion temperature to over 1400 °C, enhanced luminous intensity to over 5000 cd, reduced solid residue to under 6 %, and shortened combustion time from 7.9 s to 2.24 s. Smaller particle sizes also improved these effects. Alloys with higher Zn content produced denser smoke but had higher solid residue. This study demonstrates the potential for precise control over combustion and smoke-light effects by adjusting alloy composition and particle size, making Zn-Mg alloys promising candidates for future pyrotechnic formulations.

Self-healing, photoluminescent elastomers for 3D printing fabrication of flexible sensors

Photoluminescent materials have garnered a lot of interest lately because of their many uses in chemical sensing, bio-detection, and optoelectronic devices. However, existing photoluminescent 3D printing materials exhibit deficiencies in mechanical properties, durability, and stability, hindering their adaptation to 3D printing of complex structures or stress-varying applications, while compromising the long-term stability of devices. To address these limitations, a photoluminescent self-healing elastomers containing dynamically hindered urea bonds were developed in this study, demonstrating excellent tensile properties (560 %), high strength (4.25 MPa), and good self-healing capabilities (95.45 % healing efficiency). The elastomer also exhibits unique photoluminescent characteristics, with luminous intensity varying under significant deformations. Photoluminescent characteristics are still present in 3D printed elastomers. Moreover, the elastomers can be utilized for 3D printing complex structures and customized sensors, with the printed sensors capable of achieving segmented responses. Resistive sensors prepared from this material exhibit high sensitivity and good cyclic stability, and they are capable of detecting various human motions while providing additional sensory information through changes in luminescent intensity. This study offers new insights into the development of photoluminescent self-healing materials for multifunctional applications, including smart wearable devices, dynamic displays, and optical sensors.

A Study on Pendant and Blackboard Asymmetric Lens LED Luminaires for Optimal Illumination in Classrooms

This study examines the transformative impact of integrating pendant asymmetric lens (PAL) and blackboard asymmetric lens (BAL) LED luminaires to enhance classroom lighting, with the goals of replicating the ambient effects of natural daylight and promoting energy efficiency. This research focuses on improving the quality of learning environments through uniform, soft, and diffused lighting, which mimics sky-like illumination while adhering to sustainable energy practices. Advanced asymmetric lens LED luminaires are employed to achieve optimal lighting distribution, as indicated by luminous intensity distribution curves. Comparative analyses in diverse educational settings reveal significant improvements in ceiling illuminance, ranging from 935 to 1000 lx, and workspace illuminance from 660 to 720 lx, with reduced glare (UGR < 10). This results in bright, visually comfortable spaces conducive to learning. Additionally, the PAL and BAL solutions outperform conventional lighting systems like stretched ceilings and lightboxes by maintaining clear overhead spaces, eliminating shadows, and offering cost-effective solutions. This successful integration demonstrates a notable advancement in the development of energy-efficient, visually comfortable educational environments, contributing to the goals of sustainability and improved well-being for both students and teachers.

Introducing boron gallium nitride as carriers’ source layer for efficient near-ultraviolet microLED

Abstract This study explored the impact of boron gallium nitride (BGaN) in buffer layer and hole source layer. We employed B0.05Ga0.95N which reduced the lattice mismatch as well as the electric field. BGaN not only minimized the number of electrons leaking out of quantum wells (QWs) but also improved the hole injection. It is evident from our simulations that internal quantum efficiency (IQE) is enhanced significantly as more carriers are available for radiative recombination in multiple quantum wells (MQWs). Along with the increase in IQE, droop is also reduced in BGaN ultraviolet light-emitting diodes. Significantly high luminous power and emission intensity were observed along with slight blueshift because of minimized quantum confinement stark effect (QCSE).

Investigation of tetrazole- and bistetrazole-based lithium salts as colorants in environmentally friendly pyrotechnics

ABSTRACT Due to the harmful effects of chlorinated combustion products and strontium in currently used red-burning pyrotechnics on human health and the environment, new substitutes have to be found. A promising alternative could be using lithium-salts. While it is a literature-known problem that the generation of a lithium-based red flame color is a challenging task due to the diverse requirements of the Li(0) color species, a promising alternative could be using lithium-heterocycle salts. In this context, nitrogen-rich lithium tetrazole and bistetrazole salts, namely, lithium tetrazolate, lithium 5-aminotetrazolate, dilithium 5,5’-bistetrazolate dihydrate and dilithium 5,5’-bis(tetrazolate-1-oxide) have been investigated as potential replacements. To evaluate the performance of the salts a variety of mixtures were prepared and their pyrotechnic parameters were analyzed. Furthermore, application-specific pyrotechnic clusters and parachute flares were produced and these were also tested for burning time, dominant wavelength, spectral purity and luminous intensity. Observations on the use of lithiated nitrogen-rich salts in pyrotechnic mixtures showed a red color impression, indicating the potential of these mixtures. Further research opportunities can be pursued by refining nitrogen-rich compounds.

Effect of Standard versus Advanced Dimmable Lighting Systems on the Circadian Rhythms of Hospital Personnel

ABSTRACT The health of shift workers is seriously compromised due to circadian rhythm disruption. Not only do these shift workers lack sufficient exposure to natural light, the main circadian rhythm synchronizer, but they are also exposed to static electric lighting environments with the same luminous flux intensity throughout the entire night. Advances in lighting design make the accurate control of flux and spectra of electric lighting possible, allowing settings to be optimized for the appropriate regulation of circadian rhythms while also ensuring task performance. This research aims to quantify the effect of advanced lighting systems on the biological clock of nurses working night shifts in intensive care units, by replacing the fluorescent fixtures with dimmable luminaires. Diurnal and nocturnal levels of the main urine metabolite of melatonin, 6-sulfatoximelatonin, were assayed and a perception test of sleep quality and work performance was also carried out. The results show that the use of LED dimmable lighting results in an improvement in melatonin and cortisol levels of night shift workers, as well as improved concentration and sleep quality.

On-chip warped three-dimensional InGaN/GaN quantum well diode with transceiver coexistence characters

Featured with light emission and detection coexistence phenomenon, nitride-based multiple-quantum-well (MQW) diodes integrated chip has been proven to be an attractive structure for application prospects in various fields such as lighting, sensing, optical communication, and other fields. However, most of the recent reports are based on planar structures. Three-dimensional (3D) structures offer extra advantages in direction and polarization and absorption modulation and may start a new way to make the same thing over and over with interesting properties. In this paper, we designed and fabricated a single-cantilever InGaN/GaN MQW diode with warped 3D microstructure via standard microfabrication technology. Experimental results indicate that the strain architecture of the multi-layer materials is the key principle for the self-warped device. The planar structure will bear greater compressive stress while the warped beam part has less stress, resulting in differences in the optical and electrical performance. The strain-induced band bending highly influences the emission and detection properties, while the warped structure will introduce direction selectivity to the 3D device. As an emitter, 3D structures have a directional emission with lower turn-on voltage, higher capacitance, increased luminous intensity, higher external quantum efficiency (EQE), high -3dB bandwidth, and redshifted peak wavelength. Besides, it can serve as an emitter for directional-related optical communication. As a receiver, 3D structures have lower dark-current, higher photocurrent, and red-shifted response spectrum and also show directional dependence. These findings not only deepen the understanding of the working principle of the single-cantilever GaN devices but also provide important references for device performance optimization and new applications in visible light communication (VLC) technology.

Flame propagation analyses of aluminium coated with various concentrations of stearic acid based upon elementary reaction simulation

Coated aluminium, a novel material, has been employed in a multitude of applications. However, the thermal physicochemical properties of certain coated materials can elevate the ignition sensitivity and exacerbate explosion hazard of coated aluminium powder, posing serious thermal risks throughout the production, processing and storage. To render a theoretical basis for the prevention and mitigation of stearic acid-aluminium (SA-Al) dust explosion accidents, the flame propagation and elementary reaction sensitivity characteristics of SA-Al dust with various stearic acid concentrations were analysed by experiment and numerical simulation. Results showed that as the SA coating concentration increased from 0 % to 20 %, the flame propagation behaviour changed from dust-driven to gas-driven combustion, the flame luminous intensity and temperature abated gradually, and the average flame propagation velocities and free radical accumulation tended to first increase and then decrease, reaching maximum value in the 10 % SA-Al explosion. There may be synergistic combustion effect during Al cores and SA coating, which reflected in that a series of branch chain reactions of H and OH of SA in the initial combustion stage resulted in the accelerating melting and the forward explosion reaction kinetics of Al cores. Concurrently, the accelerated combustion of Al intensified the pyrolysis and oxidation of unburned SA-Al particles.

Exploring Asymmetric Lens–Total Internal Reflection (AL–TIR) Optics for Uniform Ceiling Illumination in Interior Lighting

This study presents a significant advancement in LED interior lighting through the development and application of Asymmetric Lens–Total Internal Reflection (AL–TIR) optics, with a focus on enhancing lighting uniformity and indoor comfort by simulating sky-like lighting distribution. AL–TIR technology employs asymmetric lenses combined with total internal reflection to efficiently redirect and spread light, achieving a controlled and even ceiling illumination suitable for various interior applications. This research explored the establishment of ideal luminous intensity curves, devised practical AL–TIR optical designs through numerical calculations, and conducted extensive simulations to assess performance in typical indoor environments. Our findings demonstrated substantial improvements in lighting uniformity, with the AL and AL–TIR systems achieving direct illuminance uniformities of 0.78 and 0.83, respectively, compared to traditional tube LEDs at 0.25. These results, validated in several office rooms, highlight the efficacy of AL–TIR optics in revolutionizing indoor lighting design by balancing optimal lighting distribution with occupant comfort and well-being.

Luminescent tunable Ba2MgY2(BO3)3:Ce3+,Tb3+ phosphors with significantly improved performance based on energy transfer

Greenlight is a sensitive band of the human eye, improving the luminous quality of the green part is crucial to the performance improvement of LED. However, the application prospects for Tb3+ are greatly limited by its 4f-4f forbidden transition. In this study, we successfully synthesized Ba2MgY2(BO3)3:Ce3+ blue phosphor which effectively enhances its luminous properties through energy transfer. By introducing both Ce3+ and Tb3+ into the Ba2MgY2(BO3)3 matrix, an energy transfer efficiency of 50.6 % is achieved between these two ions, resulting in a remarkable 13.1-fold increase in Tb3+ luminous intensity. The internal quantum efficiency (IQE) of the sample is measured at 63 %, while the external quantum efficiency (EQE) reaches 30 %. Furthermore, it exhibits good thermal stability and promising applications in temperature sensing due to the sensitivity and coordinated luminescence of Ce3+ and Tb3+ ions at different temperatures. Finally, when combined with a 365 nm chip, this sample produces a white LED (WLED) with a color rendering index (CRI) of 81.6 and a correlation color temperature (CCT) of 4330 K.

Preparation and Luminescence Property Study of Red-Emitting Na3.6Y1.8(PO4)3:Eu3+,Li+/K+ Phosphors with Excellent Thermal Stability for Light-Conversion Application.

A series of red-emitting phosphors, Na3.6Y1.8-x(PO4)3:xEu3+, have been synthesized by a high-temperature solid-phase method. The impact of the partial Li+/K+ ion substitution on the crystal structure and photoluminescence (PL) performance of Na3.6Y1.05(PO4)3:0.75Eu3+ phosphor have been investigated. Various techniques have been used for characterization of the as-obtained materials. X-ray diffraction (XRD) analysis was utilized to confirm the composites of these samples, and the morphology and element distribution were examined by scanning electron microscope (SEM) and transmission electron microscope (TEM). This study found that the developed Na3.6Y1.8-x(PO4)3:xEu3+ phosphors exhibited a prominent emission peak at ~620 nm when excited at 393 nm, which corresponded to 5D0 → 7F2 transitions of Eu3+ ions. Furthermore, the robust emission peak at ~705 nm (5D0 → 7F4) of these phosphors enables a better match with plant pigment absorption. Beyond that, the partial substitution of Li+/K+ ions probably changed the crystal structure, and reduces the symmetry around Eu3+, leading to significantly enhanced luminous intensities by 23.24% and 18.29%, with the highest quantum yields (QYs) reaching 99.85% and 96.29%, respectively. Additionally, the prepared phosphors show non-thermal quenching and superior thermal stability at elevated temperatures from 298 to 473 K. These findings and results suggest that Li⁺/K⁺-substituted Na3.6Y1.05(PO₄)₃:0.75Eu3⁺ phosphors can serve as promising red-emitting phosphors for plant lighting applications.

Enhancing anti-adhesion properties by designing microstructure - the microscopy and spectroscopy study of the intercellular bacterial response.

This study is the first one that investigates in detail the bacterial intercellular response to the high density of crystallographic defects including vacancies created in Cu by high pressure torsion. To this aim, samples were deformed by high pressure torsion and afterward, their antibacterial properties against Staphylococcus aureus were analyzed in adhesion tests. As a reference an annealed sample was applied. To avoid the influence of surface roughness, specially elaborated conditions for surface preparation were employed, which do not introduce defects and assure comparable surface roughness. The analysis of the chemical composition and thickness of passive layers by X-ray photoelectron spectroscopy showed that they were comparable for nanostructured and micrograined samples, consisting of Cu2O and CuO, and a thickness of 6nm. The interface bacterium-substrate was prepared by a focused ion beam and further analyzed by scanning transmission electron microscopy and energy dispersive spectroscopy. High pressure torsion processed Cu shows enhanced anti-adhesion properties while in contact with S. aureus than micrograined Cu. There is a linear correlation between luminous intensity and grain size-0.5. The bacterial intercellular defence mechanism includes the creation of Cu2O nanoparticles and the increased concentration of sulphur-rich compounds near these nanoparticles.