Enhanced bactericidal performance of copper doped CeO2 nanocomposites

Visualizing concealed optical information by using optical materials enables the identification of hidden threats and early risk warnings. However, current approaches to multimode optical detection using fluorescent materials often employ composite luminescence from multiple rare-earth ions, significantly limiting their application. Here, Mn2+ ions are introduced into LiAlO2 and ingeniously utilize multisite occupation to achieve visual detection of both UV and X-ray radiation. Compared to the yellow photoluminescence (PL) and green long-persistent luminescence (LPL) of LiAlO2:Mn2+, the LPL following X-ray irradiation exhibits a similar yellow emission. However, controlling temperature changes reveals a remarkable yellow-to-green color shift in the high-temperature LPL following X-ray irradiation at temperatures above 398 K. The integration of PL with LPL establishes a novel technical paradigm for designing multimode optical visualization detection materials.

Water pollution arising from persistent organic dyes constitutes a critical environmental and public health concern. In this work, ZnO nanorods (NRs), Fe3O4 nanoparticles (NPs), and their corresponding Ag@ZnO and Fe3O4@ZnO nanocomposites were successfully fabricated via a facile and cost-effective microwave-assisted hydrothermal approach. The photocatalytic activities of ZnO NRs, Fe3O4 NPs, and the as-prepared nanocomposites,including Ag@ZnO, were systematically evaluated for the degradation of malachite green (MG) dye. In addition, Ag@ZnO was further employed as an efficient active substrate for surface-enhanced Raman spectroscopy (SERS) sensing, demonstrating its dual functionality in both photocatalytic degradation and sensing applications. Structural, morphological, and optical properties were comprehensively characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman spectroscopy, diffuse reflectance spectroscopy (DRS), photoluminescence (PL), transmission electron microscopy (TEM), and dynamic light scattering (DLS) analysis. The XRD analysis confirmed the hexagonal wurtzite structure for both ZnO NRs and Ag@ZnO nanocomposites, in addition to the cubic structure for Fe3O4NPs. The FTIR and Raman studies confirmed the formation of ZnO, Ag@ZnO, and Fe3O4 NPs by revealing their distinct characteristic vibrational bands. Zeta potential results display the negative surface charge of Fe3O4 NPs, indicating their strong adsorption affinity toward positively charged malachite green (MG) dye. The DRS and PL results reveal the effect of Ag NPs on improving the optical property of ZnO and reducing the (e-h) recombination rate. Photocatalytic experiments under visible-light irradiation showed that ZnO achieved 55% degradation of MG within 90 min, whereas complete degradation was achieved using Ag@ZnO and Fe3O4@ZnO nanocomposites, highlighting their superior photocatalytic performance. In addition, Ag@ZnO exhibited excellent SERS activity, enabling the detection of MG down to 2 ppm, attributed to strong localized surface plasmon resonance and interfacial charge-transfer effects. The combined photocatalytic efficiency, adsorption capability, and SERS sensitivity demonstrate that Ag@ZnO and Fe3O4@ZnO nanocomposites are promising multifunctional materials for wastewater treatment and trace-level pollutant detection.

This work designs the synthesis of defect-engineered TiO2 nanosheets (T12 NSs) coupled with reduced graphene oxide (rGO) via a facile polyol method, demonstrating their enhanced performance in Rhodamine B (RhB) dye degradation and photoelectrochemical (PEC) water splitting. The novelty lies in the controlled introduction of oxygen vacancies (Ov's)/Ti3+ states and optimized TiO2/rGO ratios, which synergistically improve light absorption, charge separation, and catalytic efficiency compared to pristine TiO2. Structural analyses (XRD, Raman, TEM) confirmed successful hybridization between defect-rich TiO2 NSs and conductive rGO sheets, forming a hierarchical nanosheet-nanosheet heterostructure with intimate interfacial contact. Among all compositions, T2G1 (TiO2:rGO = 2:1) exhibited optimal structural and electronic properties, including enhanced lattice strain, bandgap narrowing (2.68 eV), and increased surface area (186.88 m2 g-1). Spectroscopic studies (photoluminescence (PL), time resolved PL (TRPL), EPR, and XPS) revealed that T2G1 possessed abundant surface and bulk defects, prolonged carrier lifetime (37.8 ns), and effective suppression of recombination through rGO-mediated charge transfer. Photocatalytically, T2G1 achieved a rate constant of 0.0227 min-1 at 93.9%, significantly surpassing that of pristine T12 (0.0072 min-1). In PEC studies, T2G1 displayed the highest photocurrent density, lowest overpotentials (0.909 V for the OER, 0.411 V for the HER), and smallest Tafel slopes (73 and 41 mV·dec-1), confirming superior redox kinetics and charge transport behavior. Overall, this work establishes an effective strategy for synergistic defect and interface engineering in TiO2/rGO hybrids, where oxygen vacancies, Ti3+ centers, and graphene coupling collectively enhance light harvesting and electron mobility. The optimized T2G1 nanocomposite serves as an efficient and stable material for environmental remediation and solar-driven water splitting, advancing sustainable photocatalytic technologies.

Mn-based hybrids are emerging stimuli-responsive luminescent materials, whose response mechanism is generally based on chromic behavior induced by a transition from octahedral (Oh) to tetrahedral (Td) coordination. Upon a reversible phase transition driven by H2O/Cl- ligand exchange in an octahedral configuration (Oh to Oh), an alternative chromic mechanism is reported herein. Two zero-dimensional (0D) hybrid manganese chlorides, (C4H8N4)2[MnCl4(H2O)2]·2Cl (Mn-c) and (C4H8N4)2MnCl6 (Mn-r), were synthesized, featuring 4,6-diaminopyrimidinium cations and isolated Mn-centered octahedral motifs. Structural, spectroscopic, and theoretical analyses reveal that the cyan emission of Mn-c originates from the organic cations, whereas the red emission of Mn-r stems from Mn-centered d-d transitions. Interconversion between Mn-c and Mn-r can be triggered via the H2O/Cl- ligand exchange induced by heating (>108 °C) or by soaking in hydrochloric acid, resulting in a reversible phase transition and switchable photoluminescence (PL) behavior. Leveraging this reversible chromism, anticounterfeiting patterns were fabricated. This novel Oh-Oh phase transition and the related PL switching of 0D hybrid Mn-based halides provide a new platform for developing intelligent, multicolor-responsive luminescent materials.

The heavy-atom effect plays a pivotal role in promoting intersystem crossing and enhancing phosphorescence. However, its impact on electroluminescence in light-emitting diode (LED) devices remains largely unexplored, and a clear molecular-level understanding is still lacking. Herein, we report a nearly isostructural pair of copper(I) clusters, [Cu4S(dppm)4](PF6)2 (Cu4S) and [Cu4Se(dppm)4](PF6)2 (Cu4Se), which differ solely by a single-atom substitution of the central S2- (Z=16) with Se2- (Z=34). Despite exhibiting nearly identical photoluminescence (PL) characteristics and comparable external quantum efficiencies (EQEs) in non-doped devices (5.8% vs. 5.5%), the lighter-atom-incorporated Cu4S consistently outperforms its heavier analog Cu4Se across three distinct host matrices. In particular, the Cu4S-based device employing the thermally activated delayed fluorescence (TADF) hosts achieved a maximum EQE of 20.9% at λEL=608nm, significantly surpassing that of devices with Cu4Se (12.9%). Systematic studies reveal that the S-centered cluster exhibits stronger resistance to concentration quenching, more enhanced charge transport, and a significantly reduced trap-state density, thereby effectively circumventing heavy-atom-induced non-radiative losses during electroluminescence. These findings demonstrate that single-atom variations within the cluster core decisively govern EL efficiency via an anti-heavy-atom effect and provide a new strategy for improving LED performance by exploiting this effect.

Enhancing light-matter coupling in two-dimensional (2D) semiconductors, such as transition metal dichalcogenide monolayers, remains a central challenge in nanophotonics due to their atomic thickness, which limits their interaction volume with light. Here, we demonstrate that higher-order optical resonances, including photonic guided modes (GMs) and quasi-bound states in the continuum (quasi-BICs) supported by a freestanding metasurface, provide exceptionally strong surface field enhancement, enabling efficient coupling with a tungsten disulfide (WS2) monolayer. Triangular-lattice polymer patterns on silicon nitride membranes are fabricated to realize these higher-order modes. Simulations reveal that second-order modes possess optimal surface electric-field distributions that strongly overlap with the overlying WS2 monolayer, significantly outperforming their first-order counterparts. Photoluminescence (PL) measurements confirm a remarkable PL enhancement factor of 193 for the second-order GM, over an order of magnitude greater than that of the first-order modes. These results establish higher-order modes in freestanding metasurfaces as a promising route to engineer light-matter interactions in 2D semiconductors for advanced nanophotonic and quantum photonic applications.

The application of machine learning to materials discovery is often constrained by the availability of large-scale, experimentally verified materials databases. This study presents an automatic, end-to-end framework that bridges this gap by training machine-learning predictors for materials properties on experimental data mined directly from the literature. We apply this framework to predict the photoluminescence (PL) wavelengths of thermally activated delayed fluorescence molecules. By integrating "chemistry-aware" natural language processing with automated chemical structure resolution, a dataset of 643 experimentally measured PL wavelengths was afforded. This experimentally grounded data were used to train a heterogeneous graph neural network and a ridge-regression model; both achieved mean absolute errors below 0.13 eV in less than 3 min on a personal laptop, effectively capturing complex structure-property relationships without manual feature engineering. These results demonstrate that our framework provides a fast, scalable, and generalizable pathway to generate experimentally grounded models for property predictions in organic optoelectronics.

The conversion of waste materials into value-added functional photocatalysts represents a sustainable strategy for environmental restoration. Metal-organic frameworks (Cu-BDC) synthesized from waste-derived precursors were utilized as templates to construct CuO@ZnO n-n heterojunction photocatalysts. XRD analysis confirmed the growth of wurtzite ZnO and monoclinic CuO phases, as evidenced by selected-area electron diffraction (SAED) patterns showing well-defined diffraction rings, indicating crystallinity. HRTEM revealed lattice spacings of 0.262nm and 0.232nm corresponding to ZnO (002) and CuO (111), respectively. DRS-Tauc analysis demonstrated enhanced visible-light absorption and a narrowing of the bandgap from 3.1 to 2.89eV upon CuO incorporation. CuO0.25@ZnO achieved the highest photocatalytic performance, with 99.0% and 97.7% degradation of methylene blue (MB) and rhodamine B (RhB), respectively. The degradation kinetics followed pseudo-first-order kinetics, with rate constants of 0.025 and 0.024min-1 for MB and RhB, respectively, which were higher than those for pure ZnO. Photoelectrochemical measurements and photoluminescence (PL) spectra revealed high charge separation and reduced recombination of CuO0.25@ZnO. Scavenger experiments and terephthalic acid fluorescence analysis confirmed the generation of reactive species, supporting a Z-scheme charge-transfer mechanism. Ultimately, we anticipate that this novel photocatalyst will have meaningful applications in the energy sector and environmental remediation.

The development of organic narrowband emitters faces long-standing challenges in expanding structural diversity, improving synthetic efficiency, elucidating narrowband emission mechanisms, and enhancing overall electroluminescence (EL) performance. Herein, we report a new class of narrowband emitters based on 1,2-BN-heteroarenes, enabled by a systematic design strategy that integrates planar locking, peripheral rotation, and BN-unit extension to tailor vibronic progression in alignment with the principles governing narrowband emission. They are readily synthesized using a borenium species-promoted, amine-directed one-pot borylation in yields over 80%, and exhibit tunable emission colors arising from interplay among locally excited (LE), long-range charge-transfer (CT), and short-range CT states. Representative emitters [B-N]2 and [B-N]2-DPA exhibit peak emissions at 460 and 482 nm with ultranarrow full widths at half-maximums (FWHMs) of 16 and 18 nm, respectively, and near-unity photoluminescence (PL) quantum yields. Furthermore, by employing a "hot-exciton layer" design to facilitate exciton dynamics, the corresponding narrowband organic light-emitting diodes (OLEDs) deliver a high maximum external quantum efficiency (EQE) of 29.6%, an exceptionally low efficiency roll-off of 5.7% at 1000 cd m-2, and superior operational stability compared with the control 1,4-BN-heteroarene. These findings offer new insights into the design of narrowband emitters with diverse structures and high EL performance.

Photoluminescence (PL) power efficiency, represented by the ratio of emitted to absorbed light energy, is a crucial factor for applications like radiative cooling. Yet, unlike PL quantum yield, achieving near-100% power efficiency in PL emitters remains mostly elusive. Here, we use spectrally resolved absolute radiometry method to study the PL quantum yield and power efficiency of solution-dispersed CsPbBr3 quantum dots (QDs). The samples were optimized by ligand engineering and controlled aging over the span of several months. Absorption edge changes reveal that the aging causes self-healing of intraband defect states that are otherwise contributing to a decrease of the PL quantum yield. In the optimized samples, we observed PL quantum yield reaching 100% and the PL power efficiency also approaching unity. This result means that all the absorbed excitation light energy is reemitted as luminescence. For the excitation wavelength of 532 nm, the emitted light energy comprises ∼ 80% of anti-Stokes PL and 20% of Stokes-shifted PL, while for the wavelength of 543 nm, the emission is composed entirely of anti-Stokes PL. These parameters are promising for many potential advanced applications, such as radiative cooling.

Monolayer transition metal dichalcogenides (TMDCs) are promising materials for next-generation optoelectronic devices owing to their strong excitonic responses and atomic thickness. Controlling their light emission electrically is a crucial step toward realizing practical nanoscale optoelectronic devices, such as light-emitting diodes and optical modulators. However, photoluminescence (PL) quenching in van der Waals TMDC/metal heterostructures, caused by ultrafast interlayer charge or energy transfer, impedes such electrical modulation. Here, we investigate monolayer MoSe2/bulk NbSe2 heterostructures and demonstrate that a vertical electric field tunes the PL intensity by nearly 3 orders of magnitude in bare MoSe2 and by about 1 order of magnitude in the MoSe2/NbSe2 heterostructure. First-principles calculations with spin-orbit coupling reveal stronger electronic coupling and band hybridization in the MoSe2/NbSe2 heterostructure than in conventional graphene-based counterparts. This enhances the sensitivity to a perpendicular electric field and enables a transition between direct and indirect bandgaps, strongly affecting the photoluminescence response. Unlike bare MoSe2, the heterostructure exhibits a pronounced thermal dependence of the enhancement factor, implying that the exciton lifetime dominates over interfacial transfer processes. Our findings demonstrate reversible, electric-field-driven PL control at a TMDC/metal interface, providing a pathway to electrically tunable light emission and improved contact engineering in two-dimensional optoelectronic devices.

Metal halide perovskite nanocrystals (NCs) are promising luminescent materials for optoelectronic applications. However, the highly sensitive nature of the perovskite lattice to water significantly limits the perovskite NCs for photocatalysis in aqueous phase. Here, we present a core-shell engineering strategy based on an epoxide-mediated sol-gel process to grow metal oxides on the surfaces of perovskite NCs. Benefit from the versatile inorganic metal salts, different metal oxides (such as SnO2, Al2O3, and Eu2O3) are deposited onto the perovskite core under ambient conditions. Owing to the protection of dense metal oxide shell, the exemplified SnO2@CsPbBr3 NCs display intense emission after annealing and slightly photoluminescence (PL) quenching in water over 30 days. Interestingly, they additionally behave outstanding dispersibility in water (with a zeta potential of ∼42mV). These features, combined with the type II band alignment of SnO2@CsPbBr3 NCs facilitating the photo-generated charge separation, result in a NH4 + production rate of 47µmol g-1·h-1 without any sacrificial agents. This work explores a generalized approach to produce core-shell structured perovskite NCs to enhance their aqueous stability. Besides, it also expands the aqueous applications of perovskite communities and gives a guideline for designing novel nitrogen fixation photocatalysts.

The success of near-infrared (NIR) to visible upconversion (UC) and NIR downshifting photoluminescence (PL) is mainly due to 4f-4f energy transfer (ET) interactions of lanthanide ion pairs. This concept was later extended to 3d-4f ion pairs, where Cr3+ enabled UC PL via intra-configurational spin-flip (ICSF) transition. Interestingly, recent studies reveal that heavier transition-metal ions such as Mo3+ (4d) can exhibit multiple ICSF emissions spanning the NIR-I and NIR-II regions. This finding raises a key question: can a 4d-4f ion pair be designed to achieve multimode downshifting NIR and UC PL by combining f-f and ICSF d-d transitions? Herein, we report the first synthesis of Mo3+/Er3+ -codoped Cs2NaInCl6 double perovskite, exhibiting tunable NIR-II downshifting emissions at 1095nm (Mo3+) and 1540nm (Er3+). Both emissions can be achieved by excitation of either Mo3+ d-electrons or Er3+ f-electrons through efficient 4d-4f ET, as established by temperature-dependent (300-6.3K) PL. Furthermore, this 4d-4f interaction enables the demonstration of two-photon UC PL from Mo3+ d-electrons at 700nm upon Er3+ f-electrons excitation at 980nm. This finding establishes 4d-4f interaction as a strategy to simultaneously tune downshifting and UC pathways, opening a new opportunity to tailor optical and optoelectronic materials.

Layered hybrid perovskites are attractive optoelectronic materials for a wide range of applications. This study reports three layered Ruddlesden-Popper (RP) bromides comprising small isopropylammonium (IPA+) cations: IPA2MA2Pb3Br10, IPA2DMAPb2Br7, and IPA2(IPA0.77MHy0.23)Pb2Br7 (MA+ = methylammonium, DMA+ = dimethylammonium, MHy+ = methylhydrazinium). Crucially, the IPA2(IPA0.77MHy0.23)Pb2Br7 compound represents a unique case where IPA+ cations occupy the perovskite cavities, thus acting as a perovskitizer, a dual role previously unobserved for this cation in lead halide perovskites. All compounds undergo structural phase transitions, the mechanisms of which are analyzed based on X-ray diffraction, Raman spectroscopy, and dielectric data. Nonlinear optical (NLO) and dielectric studies demonstrate that IPA2MA2Pb3Br10 exhibits second-harmonic generation (SHG) at low temperatures and bistable dielectric switching. Photoluminescence (PL) studies reveal that IPA2MA2Pb3Br10 displays narrowband purplish-blue emission attributed to free excitons (FEs), whereas the other compounds exhibit broadband PL attributed to self-trapped excitons (STEs). The broadband emission shows remarkable thermochromism, transitioning from yellow (orange) at 80 K to blue (white) at high temperatures for IPA2DMAPb2Br7 and IPA2(IPA0.77MHy0.23)Pb2Br7, respectively. These results exemplify the unusual ability of IPA+ to function simultaneously as a spacer and a perovskitizer, highlighting the critical role of A-site cations in modulating the structural, electric, and optical properties of multilayered perovskites.

In this study, novel g-C3N4/UiO-66/Ag2CrO4 ternary nanocomposites with different mass ratios of Ag2CrO4 were synthesized effectively via the precipitation method for the treatment of polluted water. Solvothermal and co-precipitation techniques were used to synthesize the UiO-66 and Ag2CrO4 nanoparticles, respectively. The precipitation process was also used to produce binary nanocomposites (g-C3N4/UiO-66 and UiO-66/Ag2CrO4). UV-visible spectrophotometry, photoluminescence (PL) study, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) evidenced ample and efficient interactions between the components within the composites. The photocatalytic activities of each nanocomposite were evaluated using aqueous solutions of model methyl orange (MO) and a real sewage sample solution collected from Hawasa Textile Industry. The photocatalytic efficiencies of the ternary nanocomposites (g-C3N4/UiO-66/Ag2CrO4, 10%, 20%, and 30% of Ag2CrO4) were found to be higher than those of single and binary nanocomposites due to synergistic effects in the composite, which favored efficient interfacial charge transfer and improved separation of photoinduced electron–hole pairs. In particular, the ternary nanocomposite containing 20% of Ag2CrO4 exhibited the highest photocatalytic activity. The effect of various experimental parameters, such as pH, initial dye concentration, photocatalyst load and scavengers' effects, on MO degradation was investigated using this g-C3N4/UiO-66/Ag2CrO4 ternary nanocomposite. Results showed that at optimum pH (2), catalyst load (0.2 g L−1) and initial dye concentration (10 ppm), the percent degradation of MO under visible-light irradiation (indoor system) was found to be 97.0% in 120 min, and in the outdoor system, it was found to be 99.6% in 40 min. The selected photocatalyst was also applied for the degradation of a real sewage sample solution, and a percent degradation of 76.2% was observed. Importantly, the catalytic efficiency did not decrease significantly even after three reaction cycles, showing it had good stability and recyclability. Hydroxide radicals (*OH) and holes (h+) were identified as the most active species in the photocatalytic process. Therefore, the g-C3N4/UiO-66/Ag2CrO4 ternary nanocomposite may be a viable option for industrial photocatalytic applications, particularly in the removal of organic dyes from wastewater.

Phosphorene is a two-dimensional (2D) material obtained from black phosphorus and has attracted considerable attention for its outstanding electronic properties, such as tunable bandgap and high carrier mobility. This review presents the structural and morphological study of direct bandgap phosphorene by atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), which verified the successful exfoliation and uniformity of the nanosheets. Also, the crystalline studies and optical properties investigated through Raman spectroscopy, X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) spectroscopy have been presented. Photoluminescence (PL) spectroscopy can measure the bandgap energy, demonstrating tunability which is dependent on the number of layers. The increase from 0.33 eV in the bulk to 1.88 eV in bilayers showcases phosphorene's band gap evolution in large-scale synthesis, with a higher-energy transition from 2.0 eV to 3.23 eV highlighting its unique optoelectronic properties. The characterization of phosphorene underscores its promising attributes for bandgap formation, with potential applications ranging from transistors to photodetectors.

The co-dependent challenges of environmental remediation and solar energy conversion necessitate the development of highly efficient, noble-metal-free photocatalytic systems, particularly those engineered to overcome rapid charge recombination while preserving high redox potential. Herein, we report the construction of an intimate PTA/Ni3V2O8 (Phosphotungstic Acid/Nickel Vanadate) nanocomposite via a facile hydrothermal method, aiming to leverage the multi-electron redox properties of PTA as a highly efficient charge mediator. Structural and optical characterization confirmed the formation of a robust heterojunction with enhanced visible-light harvesting capabilities. Under simulated solar irradiation, the optimized PTA10/Ni3V2O8 composite demonstrated remarkable dual-functional performance: achieving 94.4% degradation of Methylene Blue (MB) with a kinetic rate constant ~ 7.2-fold higher than that of pristine Ni3V2O8. Furthermore, the composite exhibited superior CO2 photoreduction activity, doubling the yield of valuable liquid fuels (HCOOH and HCHO) in 6h. Detailed mechanistic analyses, encompassing photoluminescence (PL) spectroscopy and radical trapping experiments, validated the direct Z-scheme charge transfer mechanism. This pathway successfully spatialized charge carriers, confirmed by PL quenching, and preserved their potency, evidenced by the prevalence of highly oxidizing holes (h+ on the PTA HOMO) and potent reducing species (•O2- derived from the Ni3V2O8 CB). This work establishes PTA as an effective interfacial promoter for vanadate-based materials, presenting a sustainable, high-performance Z-scheme composite for advanced environmental and energy applications.

Zinc–antimony–boro–germanate glasses highly doped with Sm2O3 were synthesized by the conventional melt-quenching method. Their structural, optical, and luminescent properties were systematically investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance UV–Vis (DR-UV–Vis), and photoluminescence (PL) spectroscopy. XRD analysis confirmed the amorphous nature of all prepared samples. XPS measurements were used to examine the surface chemical composition of the Sm2O3-doped glasses, with particular focus on verifying samarium incorporation and identifying its oxidation state after synthesis, since Sm ions act as the luminescent centers in these materials. For the sample containing the highest Sm2O3 concentration, the DR-UV–Vis spectrum exhibited ten absorption bands assigned to intra 4f electronic transitions. Based on these data, the nephelauxetic and bonding parameters were determined, indicating that increasing Sm2O3 content enhances the ionic character of the bonds within the glass network. PL spectra revealed three characteristic emission bands associated with Sm3+ luminescent centers. The emission intensity reached a maximum at 3 mol% Sm2O3, while further increases in samarium content led to luminescence quenching. The most intense emission band was in the yellow–orange region of the visible spectrum, highlighting the potential of these materials for yellow–orange-emitting solid-state laser applications. The excitation spectra show that the optical response is strongly dependent on concentration, with a sample doped with 3 mol% Sm2O3 exhibiting the highest excitation efficiency. The dominant excitation band centered near 402 nm, together with weaker bands in the blue region, indicating that these glasses are promising candidates for near-UV-pumped orange-emitting photonic devices.

In this work, optical properties of Silicon (Si) Oxide powders with Si nanocrystals (Si-nCs) embedded in a polymeric matrix (polymethyl methacrylate-PMMA) on BK7 glass and flexible substrates (acetate) are reported. The Si oxide powders were exfoliated from porous silicon layers (PSLs) with porosities of 57–98.3% obtained at 65 mA. The PSLs were obtained by electrochemical etching using, Si p-type (110), ρ=0.25-0.6 Ω-cm. For this, current densities of 65 mA and 35 mA were used with hydrofluoric acid and ethanol solution (Hf:EtOH) in (3:1), (1:3), (1:2), and (1:1) proportions respectively. To passivate and preserve the Photoluminescence (PL), the Si-oxide powders collected from exfoliation of PSLs were immersed at the polymeric matrix and deposited on acetate and BK7 glass substrates by spin-coating method. The PSLs were characterized by Photoluminescence (PL), Scanning Electron Microscopy (SEM) and X-ray spectroscopy (EDS). Subsequently, Si-oxide powders as a polymeric film exhibited strong PL emission either on acetate or on BK7 glass substrates, for which samples were characterized by PL and Raman measurements. The presence of oxidized Si-nCs were detected by Raman measurements, with average sizes between 1 to 1.5 nm, creating radiative defects (Si=O) that could be responsible of PL. The PSLs PL emission maximum position remained almost at the same wavelength even after when it is deposited on the polymer. In this manner, oxidized Si-nCs serve as effective passivating agents for PL. • SiOPF films were obtained from exfoliated PSLs and transferred onto BK7 and acetate substrates. • SiOPF exhibit PL emission in the 550–700 nm range, and their PL intensity depends on oxygen content and the initial PSLs porosity. • Raman analysis confirms oxidized Si–nCs with crystal sizes of 1–1.5 nm. • A blue shift in PL emission is observed in the SiOPF/BK7 and SiOPF/acetate samples as the oxygen concentration increases.