Conventional Light-emitting Diodes Research Articles

Epitaxial analysis of GaInP/AlGaInP red light-emitting diodes with ternary AlGaP quantum barriers for quantum efficiency enhancement

We have numerically analyzed Gallium Indium Phosphide (GaInP)/Aluminum Gallium Indium Phosphide (AlGaInP) red light-emitting diodes (LEDs) by utilizing ternary Aluminum Gallium Phosphide (AlGaP) quantum barriers instead of the conventional quaternary AlGaInP quantum barriers. The simulation findings show that the use of AlGaP quantum barriers in AlGaInP red light-emitting diodes leads to a significant increase in both electron and hole concentration in the quantum wells which in turn enhances the rate of radiative recombination compared to conventional (reference) red light-emitting diodes. Furthermore, the proposed LEDs have a substantial decline in efficiency droop from 38% to 32%.

Achieving excellent mechanical and electrical properties in transition metal oxides and rare earth oxide‐doped KNN‐based piezoceramics

AbstractPotassium sodium niobate (KNN)‐based piezoelectric ceramics have emerged as a promising alternative to lead‐based systems due to their exceptional properties. While extensive research has focused on improving the electrical properties of KNN‐based ceramics through doping and processing optimization, the concurrent investigation of their mechanical properties has been lacking. This study presents a comprehensive analysis of the mechanical and electrical properties of KNN‐based lead‐free piezoceramics doped with various transition metal oxides and rare earth oxides, based on substantial experimental data. Our findings reveal that the as‐sintered KNN‐based ceramics exhibit not only outstanding electrical properties but also remarkable mechanical robustness compared to conventional toughened lead zirconate titanate (PZT)‐based ceramics. These exceptional electrical and mechanical properties are attributed to the micro‐scale and atomic‐scale structure of the modified KNN‐based ceramics, characterized by a highly condensed structure, an inhomogeneous distribution of nano‐domain structure, and the presence of amorphous intergranular films at grain boundaries.

Two-layered Lu3Al5O12:Ce/ Y3Al5O12:Ce composite phosphor converter for white light-emitting diode devices

Thermal management poses a significant challenge for conventional phosphor-converted white LEDs (pc-WLEDs), thereby affecting their overall efficiency. Single crystal phosphors (SCPs), such as Y3Al5O12:Ce (YAG:Ce), exhibit enhanced efficiency and thermal stability in comparison to conventional powder phosphors. The garnet Lu3Al5O12:Ce (LuAG) has been characterized as a green phosphor with even higher than YAG:Ce temperature stability, making it suitable for use in high-power WLEDs. However, there are some difficulties in obtaining suitable components with longer emission wavelengths in LuAG:Ce phosphors. As a way to solve this issue, the article suggests the growth of LuAG:Ce single crystalline films onto YAG:Ce substrates, thereby producing a composite color converter that possesses adjustable parameters. This paper presents a comprehensive analysis of the fabrication process as well as the characteristics of a two-layered LuAG:Ce film/YAG:Ce substrate composite color converter. The results of investigations of the structural, luminescence and photoconversion characteristics of composite color converters were presented as well. This study includes also consideration of the effect of varying LuAG:Ce film thicknesses and concentrations of Ce3+ in YAG:Ce substrates on photoconversion characteristics of composite converters.

Preparation of BaAl2-xGaxSi2O8:Ce3+, M+ (Li, Na, K) blue-cyan phosphors based on charge compensation and cation substitution strategies and luminescence performance study

Highly efficient blue-cyan phosphors can fill the cyan gap in conventional white light-emitting diode (LED) devices to improve the spectral continuity while effectively increasing the white LED colour rendering index (Ra). In this study, Ba0·94Al2-xGaxSi2O8:0.06Ce3+, M+ (Li, Na, K, x = 0–0.8) blue-cyan phosphors with a feldspar structure were prepared by a high-temperature solid-phase method using charge compensation and cation substitution strategies. The barium (Ba) vacancy due to the charge-imbalance substitution of Ce3+ is compensated by the different charge compensators Li+, Na+, and K+. The charge compensators affect the luminescence performance of the samples, with the K+-compensated samples showing the greatest enhancement, with intensities up to 1.8 times that of the uncompensated samples. The cation substitution strategy using Ga3+ to partially replace Al3+ further improves the luminescence performance of the Ba0·94Al2Si2O8:0.06Ce3+, 0.04 K+ sample, and the excitation band is also improved. In this case, the luminescence intensity of the Ba0·94Al2Si2O8:0.06Ce3+ luminescent material is increased by a factor of 6, and a broadband blue-cyan phosphor with a full-width at half-maximum of 118 nm containing blue, cyan and green is obtained. The co-doping of charge compensators and partial cation substitution improved the luminescence performance of phosphors. The representative sample Ba0·94Al1.6Ga0.4Si2O8:0.06Ce3+, 0.04 K+ has a luminescence intensity at a temperature of 150 °C that is 83.2% of that at room temperature and good thermal stability. The combination of 365 nm near-ultraviolet (NUV) LED chips with Ba0·94Al1.6Ga0.4Si2O8:0.06Ce3+, 0.04 K+ and the commercial red powder (Ca, Sr)AlSiN3:Eu2+ yields a white LED device with an Ra of up to 93 and a correlated colour temperature (CCT) of 4825 K. These results show that the blue-cyan phosphor complements the cyan component while simplifying the manufacturing process of white LEDs.

Critical evaluation of effects of polymer concentrations on the set time and compressive strength of cement slurries

Thickening time and compressive strength of cement slurry are very critical parameters in well cementing. Thickening or pump time and compressive strength of cement slurries are greatly affected by the slurry weight and temperature. Conventional Lead slurries usually require extenders such as bentonite and some polymers to stabilize the slurry and minimize excessive free fluid. The low slurry weight of lead slurries usually give rise to long pumping or set time and low compressive strength. Some of the polymers also retard the setting of the cement slurry. Therefore, this study focuses on the investigation of the performance of sodium silicate in comparison with gypsum and polyanionic cellulose (PAC-R) as extenders for cement slurries. The concentration of the light weight additives tested were 0%, 1.5% and 3.0% by weight of cement (bwoc) for 12.5ppg slurry using sea water. The slurry stability, compressive strength and quick set time were determined at room temperature. The higher the concentration of the lightweight additives, the more stable is the slurry, best stability was observed for recipe with sodium silicate while the slurry with PAC-R could not mix at 3% bwoc. At the lower concentrations, for sodium silicate, compressive increases and decreases for gypsum. The mixture with PAC-R had zero compressive strength. The gypsum has retarding effect on the slurry while the sodium silicate has accelerating effect. Conclusively, sodium silicate and gypsum powder performed very well as cement extender at optimum concentration, with the former showing the best performance and impacting accelerating properties that will be useful fort low temperature cementing.

Assessment of injuries patterns produced by a 9mm P.A.K "rubber ball" blank firing weapon: porcine model.

The use of less lethal weapons aims to mitigate civilian casualties caused by firearm use. However, due to numerous cases in which these weapons caused serious injuries, even lethal injuries, both legislation and the forensic field are interested in characterizing and regulating them better. In the forensic field, there is a lack of strong research about injury patterns of these weapons which makes it difficult to identify the type of weapon employed. In this study, the main objective was to characterize the injury pattern produced by the impact of the 9mm P.A.K. projectile. A porcine model was used. Four different distances were studied: firm contact, 10cm, 60cm and 110cm, using 3 of the more representative anatomical sites: the head, the hind leg and the ribs. The average measurement of the entrance orifice varied according to the anatomical site, being 6.67mm wide and 6.25mm long in the thorax, 7.3mm wide and 8.8mm long in the hind legs, and 7.62mm wide and 7.54mm long in the head. The variation in width and length measurements was not found to be directly related to the shot distance. The gunshot residues had similar characteristics to those of conventional lead projectiles, however there was more unburned powder deposit near the wounds, with a less dense soot and more dense powder tattoo. Depth varied widely regardless of tissue and firing distance, although loss of penetrating power and injury is observed as one moves away from the target.

Upconversion electroluminescence in 2D semiconductors integrated with plasmonic tunnel junctions.

Plasmonic tunnel junctions are a unique electroluminescent system in which light emission occurs via an interplay between tunnelling electrons and plasmonic fields instead of electron-hole recombination as in conventional light-emitting diodes. It was previously shown that placing luminescent molecules in the tunneling pathway of nanoscopic tunnel junctions results in peculiar upconversion electroluminescence where the energy of emitted photons exceeds that of excitation electrons. Here we report the observation of upconversion electroluminescence in macroscopic van der Waals plasmonic tunnel junctions comprising gold and few-layer graphene electrodes separated by a ~2-nm-thick hexagonal boron nitride tunnel barrier and a monolayer semiconductor. We find that the semiconductor ground exciton emission is triggered at excitation electron energies lower than the semiconductor optical gap. Interestingly, this upconversion is reached in devices operating at a low conductance (<10-6 S) and low power density regime (<102 W cm-2), defying explanation through existing proposed mechanisms. By examining the scaling relationship between plasmonic and excitonic emission intensities, we elucidate the role of inelastic electron tunnelling dipoles that induce optically forbidden transitions in the few-layer graphene electrode and ultrafast hot carrier transfer across the van der Waals interface.

Evaluation of Improved Imaging Properties with Tungsten-Based Parallel-Hole Collimators: A Monte Carlo Study

Abstract Objectives The purpose of a parallel-hole collimator in a scintillation camera system is to transmit only those photons that have an emission angle close to the direction of the hole. This makes it possible to receive spatial information about the origin of the emission, that is, radioactivity decay. The dimension, shape, and intrahole thickness determine the spatial resolution and, by a tradeoff, sensitivity. The composition of the collimator material also plays an important role in determining a proper collimator. In this study, we compared tungsten alloys as a potential collimator material replacement for the conventional lead antimony material used in most of the current camera systems. Materials and Methods Monte Carlo simulations of a commercial scintillation camera system with low energy high resolution (LEHR), medium-energy (ME), and high-energy (HE) collimators of lead, tungsten, and tungsten-based alloy were simulated for different I-131, Lu-177, I-123, and Tc-99m sources, and a Deluxe rod phantom using the SIMIND Monte Carlo code. Planar images were analyzed regarding spatial resolution, image contrast in a cold source case, and system sensitivity for each collimator configuration. The hole dimensions for the three collimators were those specified in the vendor's datasheet. Results Using Pb, W, and tungsten alloy (Wolfmet) as collimator materials, the full width at half maximum (FWHM) measures for total counts (T) for LEHR with Tc-99m source (6.9, 6.8, and 6.8 mm), for ME with Lu-177 source (11.7, 11.5, and 11.6 mm), and for HE with I-131 (6.2, 13.1, and 13.1 mm) were obtained, and the system sensitivities were calculated as 89.9, 86.1, and 89.8 cpsT/MBq with Tc-99m source; 42.7, 17.4, and 20.9 cpsT/MBq with Lu-177 source; and 40.1, 69.7, and 77.4 cpsT/MBq with I-131 source. The collimators of tungsten and tungsten alloy (97.0% W, 1.5% Fe, 1.5% Ni) provided better spatial resolution and improved image contrast when compared with conventional lead-based collimators. This was due to lower septal penetration. Conclusion The results suggest that development of a new set of ME and HE tungsten and tungsten alloy collimators could improve imaging of I-131, Lu-177, and I-123.

An Innovative Concept of Membrane-Free Redox Flow Batteries with Near-Zero Contact Distance Between Electrodes.

Given that the ion-exchange membrane takes up more than 30% of redox flow battery (RFB) cost, considerable cost reduction is anticipated with the membrane-free design. However, eliminating the membrane/separator would expose the membrane-free RFBs to a higher risk of short-circuits, and the dendrite growth may aggravate this issue. The current strategy based on expanding distances between electrodes is proposed to address short-circuit issues. Nevertheless, this approach would decrease the energy efficiency (EE) and could not restrain dendrite growth fundamentally. Herein, an inexpensive and electron-insulating boron nitride nanosheets (BNNSs)-Nylon hybrid interlayer (BN/Nylon) is developed for general membrane-free RFBs to achieve "near-zero distance" contact between electrodes. And the Lewis acid sites (B atoms) in BNNS can interact with the Lewis base anions in electrolytes, enabling a reduced Pb2+concentration gradient. Additionally, the ultrahigh thermal conductivity and mechanical strength of BNNSs promote the uniform plating/stripping process of Pb and PbO2. Compared with conventional soluble lead RFBs, introducing BN/Nylon interlayers boosts EE by ≈38.2% at 25mAcm-2, and extends the cycle life to 100 cycles. This innovative strategy premieres the application of the BN/Nylon interlayer concept, offering a novel perspective for the development of general membrane-free RFBs.

Gradient Alloy Shell Enabling Colloidal Quantum Wells Light-Emitting Diodes with Efficiency Exceeding 22.

Colloidal quantum well (CQW) based light emitting diodes (LEDs) possess extra-high theoretical efficiency, but their performance still lags far behind conventional LEDs due to severe exciton quenching and unbalanced charge injection. Herein, we devised a gradient composition CdxZn1-xS shell to address these issues. The epitaxial shell with gradient composition was achieved through controlling competition between Cd2+ and Zn2+ cations to preferentially bind to the anions S2-. Thus, exciton quenching was suppressed greatly by passivating defects and reducing nonradiative recombination, thereby achieving near-unity photoluminescence quantum yield (PLQY). The gradient energy level of the shell reduced the hole injection barriers and increased the hole injection efficiency to balance the charge injection of LEDs. As a result, the LEDs achieved a high external quantum efficiency (EQE) of 22.83%, luminance of 111,319 cd/m2 and a long operational lifetime (T95@100 cd/m2) over 6,500 h, demonstrating the state-of-the-art performance for the CQW based LEDs.

A review of current practices on lead ions removal from different aqueous streams

Toxic heavy metals like Lead are destructive to humans and the environment when existing above their threshold limits. Several conventional lead abatement methods are used in wastewater treatment plants to restore the ecology, food supply, and human and animal health. Many tactics are used to remove harmful Pb metals, like ion exchange, chemical precipitation, membrane filtration, and coagulation. These have a few principal approaches for removing metal ions from used water. Rapid developments in tailor-made materials science have proved to remove Lead metal using ion exchange resins, zeolite, polymeric membranes, and ionic liquids due to their low cost, surface accessibility, and unique benefits. This review paper has studied the detailed benefits and shortcomings of removing lead ions from wastewater using numerous materials, processes of production, possibly destructive properties on public health, and potential hybrid routes. In addition, this work observes the present advancements and developments in lead mitigation tools using different techniques for the past five years. Furthermore, this research review opens up to study of other materials' diverse applications in removal processes.

Development and evaluation of modified lead gloves to reduce hand radiation dose during interventional radiological procedures

We developed lead gloves that minimize radiation dose to the operator's hands during interventional radiological procedures and that do not impede the operator's surgical capabilities. Existing lead gloves can protect the operator's hands by shielding radiation, but use of such gloves may impair preception sensitivity, resulting in a reduction in the operator's surgical ability. Accordingly, in this study, we developed modified lead gloves that can reduce radiation dose while maintaining operator sensitivity during procedures by modifying the operator's main surgical finger area in existing lead gloves. To evaluate the performance of developed modified lead gloves, radiation was applied in surgical conditions without gloves and with surgical gloves, lead gloves, and modified lead gloves. The radiation dose was evaluated for each condition. When the modified lead gloves were worn, the degree of shielding was similar to when conventional lead gloves were worn. Based on these results, if the operator wears modified lead gloves during interventional radiological procedures, they will protect the hands from radiation while maintaining physical sensitivity in the hands.

Assessing public street lighting in Morocco: evaluating efficiency and the impact of geometrical parameters on luminance

The main objective of this study is to present a bench marking of the public street lighting in typical road in Morocco. The study deals with a comparison between the conventional technology used in Moroccan road and the LED technology. The simulated system is based on road with two directions and a sidewalk, three arrangements type of pole layout are treated (Left, Middle and Two sides arrangement). Also, in this paper deals with a parametric analysis based on the variation of boom angle, light Center high and the pole distance in order to determine the luminance of each arrangement at each pole distance. The simulation is carried out using two luminaries, the fi rst one represents a conventional technology and LED lamp. The founding of this paper shows that the LED lamp present a high luminance value of 20 cd/m² for a pole distance of 10m and boom angle of 0°, in comparison with the conventional lamp that present a luminance of 8 cd/m² at the same condition. The left arrangement type shows the best energy effi ciency indicators such as DE and power per km, this means that this disposition is less consuming of energy and acceptable luminance values. Therefore, these two indicators play a crucial role in enhancing the effi ciency of the lighting.

Synthesis of Red, Green, and Blue Carbon Quantum Dots and Construction of Multicolor Cellulose‐Based Light‐Emitting Diodes

Light‐emitting diodes (LEDs) are widely used in lighting and display applications. Carbon quantum dots (CQDs), which have high biocompatibility, high resistance to photobleaching, and full‐spectrum luminescence, have inherent advantages as fluorescent materials for LED devices. Herein, multicolor CQDs are prepared by a new reagent engineering strategy due to the difference of effective conjugate length and the surface electron‐withdrawing groups of CQDs. White CQDs are realized by mixing blue, green, and red CQDs proportionally. Then, the aggregation‐caused quenching phenomenon of CQDs is suppressed through the hydrogen‐bonding network of cellulose nanofibrils (CNFs). Multicolor fluorescent films are prepared from CQDs and CNFs by simple mixing and casting methods. Finally, thin‐film encapsulation based on the photosensitive resin ABPE‐10 coating can be realized and rapidly assembles into fluorescent films with different light‐emitting colors into LED devices, leading to have superior thermal performance compared with conventional LEDs. White LEDs have excellent white‐light illumination performance, with Commission Internationale de L’Eclairage color coordinates of (0.33, 0.37), a correlated color temperature of 5688 K, and a color rendering index of 86. This strategy provides a convenient and scalable pathway for low‐cost, environmentally friendly, and high‐performance CQDs‐based LEDs.

The spectrally resolved photoluminescence decay in YAG:Er, ZnO and SiO2 crystals

We present an optical setup for measuring spectrally resolved photoluminescence (PL) mean decay time using conventional UV LED with sinusoidal excitation and a phase shift method. The phase sensitive detection was applied on the Er-doped yttrium aluminium garnet single crystal (YAG:Er, grown by the micro-pulling-down method) and hydrothermally grown zinc oxide micro-crystallites (ZnO). Commercial ZnO and silicon oxide (SiO2) microcrystalline powders were measured for comparison. SiO2 powder was annealed in O2 plasma at 500 °C for cleaning. While YAG:Er shows well resolved greenish PL peaks with mean decay time about 15 μs related to the Stark splitting of Er3+ (4f11) states and ZnO micro-powder broad reddish PL with similar PL decay time, the plasma treated SiO2 powder shows weak bluish defect-related PL with significantly faster mean decay times below 100 ns.

Physical, mechanical, and microstructural characterisation of tungsten carbide-based polymeric composites for radiation shielding application

Polymeric based composites have gained considerable attention as potential candidates for advanced radiation shielding applications due to their unique combination of high-density, radiation attenuation properties and improved mechanical strength. This study focuses on the comprehensive characterisation of polymeric based composites for radiation shielding applications. The objective of this study was to evaluate the physical, mechanical and microstructural properties of tungsten carbide-based epoxy resin and tungsten carbide cobalt-based epoxy resin for its efficiency in shielding against gamma-rays ranging from 0.6 up to 1.33 MeV. Polymeric composites with different weight percentages of epoxy resin (40 wt%, 35 wt%, 30 wt%, 25 wt%, 20 wt%, 15 wt% and 10 wt%) were fabricated, investigated and compared to conventional lead shield. The attenuation of the composites was performed using NaI (Tl) gamma-ray spectrometer to investigate the linear and mass attenuation coefficients, half value layer, and mean free path. High filler loadings into epoxy resin matrix (90% filler/10% epoxy) exhibited excellent gamma shielding properties. Mechanical properties, such as hardness were examined to assess the structural integrity and durability of the composites under various conditions. The fabricated composites showed a good resistance, the maximum hardness was attributed to composites with small thickness. The high loading of fillers in the epoxy matrix improved the microhardness of the composites. The distribution of the filler powder within the epoxy matrix was investigated using FESEM/EDX. The results revealed the successful incorporation of tungsten carbide and cobalt particles into the polymer matrix, leading to increased composite density and enhanced radiation attenuation. The unique combination of high-density, radiation attenuation, and improved mechanical properties positions polymeric based composites as promising candidates for radiation protection field.

Phosphor-free micro-pyramid InGaN-based white light-emitting diode with a high color rendering index on a β-Ga2O3 substrate.

We demonstrate the InGaN/GaN-based monolithic micro-pyramid white (MPW) vertical LED (VLED) grown on (-201)-oriented β-Ga2O3 substrate by selective area growth. The transmission electron microscopy (TEM) reveals an almost defect-free GaN pyramid structure on (10-11) sidewalls, including stacked dual-wavelength multi-quantum wells (MQWs). From the electroluminescence (EL) spectra of the fabricated MPW VLED, a white light emission with a high color rendering index (CRI) of 97.4 is achieved. Furthermore, the simulation shows that the light extraction efficiency (LEE) of the MPW VLED is at least 4 times higher compared with the conventional planar LED. These results show that the MPW VLED grown on β-Ga2O3 has great potential for highly efficient phosphor-free white light emission.

Temperature and pressure induced structural transitions of lead iodide perovskites

Conventional lead halide perovskites, APbI3, are excellent materials for photovoltaics and other optoelectronic applications. This perspective highlights the temperature and pressure induced structural phase transitions of CsPbI3, MAPbI3 and FAPbI3.

Spectral tunability of K2Lu(WO4)(PO4): Dy3+, Eu3+ phosphors and remote luminescent layers for high-quality white light

Dy3+ and Eu3+ co-doped phosphors have been emerged as potential candidate to generate high-quality white light under the ultraviolet (UV) or near ultraviolet (NUV) excitation for health and comfort lighting. Herein, K2Lu(WO4)(PO4) crystal has been newly developed to accommodate rare earth ions, such as Dy3+ and Eu3+ ions, to achieve spectral tunability of high-quality white light. Under NUV excitation, Dy3+ singly-doped K2Lu(WO4)(PO4) phosphors exhibit the desired blue emission at 486 nm and yellow emission at 575 nm, attributed to the electric dipole transition 4F9/2 → 6H15/2 and the magnetic dipole transition 4F9/2 → 6H13/2 transitions of Dy3+ ions, respectively. Interestingly, the emission color can be facilely adjusted from cold white light to pink light under 365 nm NUV excitation due to the co-doping of Eu3+ ions in K2Lu(WO4)(PO4): 0.05Dy3+ sample. Further, the remote luminescent layers containing K2Lu(WO4)(PO4): 0.05Dy3+, 0.20Eu3+ phosphor can be printed on glass substrate by screen printing technique to generate high-quality white light with the correlated color temperature (CCT) of 5433 K and color rendering index (CRI) of 87. Moreover, the remote luminescent layers exhibit better heat dissipation performance compared to conventional encapsulated LEDs and can be used as a multicolor emitting candidate for high-power white LEDs.

Sensitization of TiO2 NPs with curcumin and chlorella and photocatalytic performance for degradation of phenol and organic dyes

Titanium dioxide (TiO2) is the most used semiconductor for heterogeneous photocatalysis. However, there is a limitation to its use because it is only activated under ultraviolet radiation (below 390 nm). Sunlight comprises only 5 % of UV radiation and consequently limits the use of TiO2 as a photocatalyst. Several studies were performed to extend the photocatalytic activity of TiO2 to the visible spectrum. Therefore, in this work two TiO2 NPs (S1 and P25) were sensitized with natural extracts to extend their photocatalytic activity to the visible light. In a previous work of our group TiO2 nanoparticles with a high surface area were synthesized via controlled precipitation method (called S1). In sequence they were wet sensitized with extracts of curcumin and Chlorella pyrenoidosa microalga to extend their photocatalytic activity to the visible light. After sensitization with natural extracts, the samples were characterized. The photoactivity of the NPs was evaluated for the degradation of phenol and the methylene blue, Rhodamine B and methyl orange dyes, under visible light using conventional LED lamps (380 to 780 nm). By XRD analysis all samples showed anatase and rutile as the only phases. The NPs sensitized with the highest content of chlorella and curcumin showed the highest mass loss (16 and 49 wt%, respectively), determined by DSC/TG, proving the adsorption of both extracts. Chemical bonds ascribed to both extracts were observed by the FTIR analysis. In addition, the NPs sensitized with the less content of the extracts presented the higher specific surface areas (∼207 m2/g, by BET analysis). The NPs are stable in water solution, presenting a zeta potential of −33 mV. Chlorella shows a larger absorption spectrum than curcumin. The calculated band gaps are 2.25 eV for chlorella and 2.07 eV for curcumin. Finally, the sensitization did not change the size or shape of the NPs (FESEM). The results of the photocatalytic activity tests show that the sensitized S1 NPs show higher efficiency than the commercial sensitized P25 NPs for the discoloration of the dyes, reaching 97 % for rhodamine B dye.