Blue Light-emitting Diodes Research Articles

High-Performance Green and Blue Light-Emitting Diodes Enabled by CdZnSe/ZnS Core/Shell Colloidal Quantum Wells.

The unique anisotropic properties of colloidal quantum wells (CQWs) make them highly promising as components in nanocrystal-based devices. However, the limited performance of green and blue light-emitting diodes (LEDs) based on CQWs has impeded their practical applications. In this study, alloy CdZnSe core CQWs with precise compositions are tailored via direct cation exchange (CE) from CdSe CQWs with specific size, shape, and crystal structure and utilized hot-injection shell (HIS) growth to synthesize CdZnSe/ZnS core/shell CQWs exhibiting exceptional optoelectronic characteristics. This approach enabled the successful fabrication green and blue LEDs manifesting superior performance compared to previously reported solution-processed CQW-LEDs. The devices demonstrated a remarkable peak external quantum efficiency (20.4% for green and 10.6% for blue), accompanied by a maximum brightness 347,683cd m-2 for green and 38,063cd m-2 for blue. The high-performance represents a significant advancement for nanocrystal-based light-emitting diodes (Nc-LEDs) incorporating anisotropic nanocrystals. This work provides a comprehensive synthesis strategy for enhancing the efficiency of Nc-LEDs utilizing anisotropic nanocrystals.

Performance Analysis and Characterization of Natural Dye-sensitized Solar Cells (DSSCs) of Titanium Oxide (TiO2) Thin Film

Dye-sensitized solar cells (DSSCs) thin films of titanium oxide (TiO2) sensitized with the dyes of the almond and copper leaves extracted using ethanol and water (AE, AW, CE and CW) each, have been successfully deposited on FTO conductive glass substrate using the Dr Blading method. The deposited TiO2-DSSC thin films were subjected to UV-Vis spectroscopy, X-ray diffraction, scanning electron microscopy and I-V characteristics analysis to determine their optical, structural, morphological properties and solar cell parameters respectively. The results of the analysis showed that copper leaves dye-sensitized films (CE and CW) has absorbance is in the range of 0.45 to 0.9 and 0.25 to 0.45 respectively within the visible (VIS) regions. The absorbance of the films sensitized with almond leaves dye is lower in the range of 0.15 - 0.25 for AE and 0.04 – 0.09 for AW within the region. The percentage transmittance of the films was found to be in the range of 82.5% – 90% for the film AW, 35% – 55% for CW while the film AE has the lowest value of the order 12.5% - 35% within the VIS region. The reflectance percent of the films were generally low with the film CE having the highest value in the range of 27%-43%, CW in the range 17.5% - 26%, AE in the range 10% - 15%, while the film AW has values in the range 2.5% - 5.5% within the VIS region. All the deposited DSSCs films have high refractive index values throughout the VIS region. The bandgap energy values obtained for the films are 2.5 eV for film CE, 2.6 eV for CW, and 2.4 eV for the films AE and AW each. These are in the range of wide bandgap energies and are favourable for application in the device that required high temperature and fabrication of blue LEDs. The results of the structural analysis on the deposited thin films showed that both the films exhibited crystalline structure with crystallite sizes of 24.55 nm for CE, 27.68 nm for CW, 22.27 for AE and 36.30 for AW films. The films have low cell conversion efficiency but still within the margin of error for most DSSCs materials.

Manipulating Electron-Phonon Coupling for Efficient Tin Halide Perovskite Blue LEDs.

Low-dimensional perovskites have opened up a new frontier in light-emitting diodes (LED) due to their excellent properties. However, concerns regarding the potential toxicity of Pb limited their commercial development. Sn-based perovskites are regarded as a promising candidate to replace Pb-based counterparts, while they generally exhibit strong electron-phonon coupling and consequently blue emission quenching at room temperature (RT), thus the Sn-based perovskite blue LED devices have not yet been reported. Herein, the luminescence properties are regulated by assembling a rigid organic skeleton within perovskite structure, and the protonated 4-bromobenzylamine (BrPMA+ = C7H9BrN+) is employed as A site cation to synthesize a 100-oriented 2D perovskite (BrPMA)2SnBr4, which exhibits a strong lattice rigidity via strong intermolecular interaction and consequently weak electron-phonon coupling, achieving the excellent blue PL emission at RT. The high quality (BrPMA)2SnBr4 perovskite thin films are obtained by further inhibiting oxidation and promoting crystallization. Finally, the Sn-based perovskite blue emission LED is successfully fabricated for the first time at 467nm with a champion EQE of 1.3% and a maximum brightness of 800cdm-2. This work gives insights into the luminescence mechanism of Sn-based perovskites and provides a new theoretical basis for the development of lead-free blue LEDs.

Metal‐free visible‐light‐induced direct synthesis of alkyl‐substituted phosphonodithioates from white phosphorus (P4)

The direct synthesis of organic phosphorus compounds from white phosphorus (P4) is a longstanding challenge in organic synthesis. Here, we present a novel visible light‐induced three‐component functionalization reaction that integrates P4, disulfide compounds, and N‐hydroxyphthalimide (NHPI) esters to produce alkyl‐substituted phosphonodithioates in a one‐pot process. Using 2,4,5,6‐tetrakis(carbazol‐9‐yl)‐1,3‐dicyanobenzene (4CzIPN) as a photocatalyst, blue LEDs (456 nm) as the light source, and N,N‐diisopropylethylamine (DIPEA) as the reducing agent in an acetone‐toluene solvent system, this method achieves moderate to good yields of structurally diverse phosphonodithioates. The reaction proceeds under mild conditions, ensures complete conversion of P4, avoids chlorination, and uses inexpensive, readily available starting materials, offering potential for large‐scale applications.

Growth, Quality, and Nitrogen Metabolism of Medicago sativa Under Continuous Light from Red–Blue–Green LEDs Responded Better to High Nitrogen Concentrations than Under Red–Blue LEDs

Alfalfa is a widely grown forage with a high crude protein content. Clarifying the interactions between light quality and nitrogen level on yield and nitrogen metabolism can purposely improve alfalfa productivity in plant factories with artificial light (PFAL). In this study, the growth, quality, and nitrogen metabolism of alfalfa grown in PFAL were investigated using three nitrate-nitrogen concentrations (10, 15, and 20 mM, labeled as N10, N15, and N20) and continuous light (CL) with two light qualities (red–blue and red–blue–green light, labeled as RB-C and RBG-C). The results showed that the adaptation performance of alfalfa to nitrogen concentrations differed under red–blue and red–blue–green CL. Plant height, stem diameter, leaf area, yield, Chl a + b, Chl a, Chl b, crude protein contents, and NiR activity under the RB-CN15 treatment were significantly higher than RB-CN10 and RB-CN20 treatments. The RB-CN20 treatment showed morphological damage, such as plant dwarfing and leaf chlorosis, and physiological damage, including the accumulation of proline, H2O2, and MDA. However, the difference was that under red–blue–green CL, the leaf area, yield, and Chl a + b, carotenoid, nitrate, and glutamate contents under RBG-CN20 treatment were significantly higher than in the RBG-CN10 and RBG-CN15 treatments. Meanwhile, the contents of soluble sugar, starch, and cysteine were significantly lower. However, the crude protein content reached 21.15 mg·g−1. The fresh yield, dry yield, stomatal conductance, leaf area, plant height, stem diameter, crude protein, GS, and free amino acids of alfalfa were positively correlated with increased green light. In addition, with the increase in nitrogen concentration, photosynthetic capacity, NiR, and GOGAT activities increased, promoting growth and improving feeding value. The growth, yield, photosynthetic pigments, carbon, nitrogen substances, and enzyme activities of alfalfa were significantly affected by the interaction between nitrogen concentration and light quality, whereas leaf/stem ratio and DPPH had no effect. In conclusion, RB-CN15 and RBG-CN20 are suitable for the production of alfalfa in PFAL, and green light can increase the threshold for the nitrogen concentration adaptation of alfalfa.

Nondestructive halide exchange via SN2-like mechanism for efficient blue perovskite light-emitting diodes

Blue perovskite light-emitting diodes (PeLEDs) still remain poorly developed due to the big challenge of achieving high-quality mixed-halide perovskites with wide optical bandgaps. Halide exchange is an effective scheme to tune the emission color of PeLEDs, while making perovskites susceptible to high defect density due to solvent erosion. Herein, we propose a versatile strategy for nondestructive in-situ halide exchange to obtain high-quality blue perovskites with low trap density and tunable bandgaps through long alkyl chain chloride incorporated chloroform post-treatment. In comparison with conventional halide exchange method, the ionic exchange mechanism of the present strategy is similar to a bimolecular nucleophilic substitution process, which simultaneously modulates perovskite bandgaps and inhibits new halogen vacancy generation. Consequently, efficient PeLEDs across blue spectral regions are obtained, exhibiting external quantum efficiencies of 23.6% (sky-blue emission at 488 nm), 20.9% (pure-blue emission at 478 nm), and 15.0% (deep-blue emission at 468 nm), respectively.

Ultrabroadband Visible-Near-Infrared Phosphor CaY2Mg2Ge3O12:Ce3+/Cr3+ and Its Temperature Sensing.

With the wide application of phosphor conversion light-emitting diode (pc-LED) in nondestructive testing, spectral illumination, near-infrared (NIR) spectroscopy, agricultural medical care, and other fields, the ultrabroadband visible-NIR tunable emission phosphor is considered as the most promising fluorescent material. In this paper, Ce3+/Cr3+ single-doped and codoped CaY2Mg2Ge3O12 phosphors were successfully prepared by using the high-temperature solid-state method. Ce3+ and Cr3+ codoped phosphors show ultrabroadband visible-NIR emission from 480 to 900 nm with two emission peaks at visible 556 nm and infrared 758 nm. Interestingly, energy transfer and occupation competition are shown in the Ce3+/Cr3+ codoped CaY2Mg2Ge3O12. Additionally, the luminescence of Ce3+/Cr3+ codoped CaY2Mg2Ge3O12 is adjusted with the doping ion concentration or ambient temperature changes. The energy transfer mechanism of Ce3+-Cr3+ is studied according to Dexter's formula, and a dipole-dipole interaction is determined. Furthermore, its superior sensitivity with Sr of 1.331%K-1 at 298 K was calculated by using the fluorescence intensity ratio. The pc-LED device was fabricated by combining a commercial 460 nm blue LED chip with CaY2Mg2Ge3O12:Ce3+, Cr3+ phosphors, producing yellow-white light and broadband NIR light, indicating great potential application in night vision pc-LEDs.

Multiple Carbazole-Benzonitrile (CzBN) Derived TADF Molecules Targeting Efficient and Stable Blue OLEDs.

Thermally activated delayed fluorescence (TADF) materials have emerged as a promising avenue for developing efficient and stable blue organic light-emitting diodes (OLEDs) without incorporating heavy metals. Among the numerous donor-acceptor architectures explored, the carbazole (Cz) and benzonitrile (BN) combination has demonstrated exceptional potential for blue OLED applications. Herein, we delve into the recent advances in TADF materials based on the Cz-BN framework, with a particular focus on design strategies to accelerate exciton dynamics and improve material stability through kinetic and thermodynamic optimization. Eventually, challenges associated with the Cz-BN systems in blue OLEDs, as well as prospective research directions that could unlock the full potential of this intriguing category of materials, are also discussed.

The effect of supplemental LED lighting in the range of UV, blue, and red wavelengths at different ratios on the accumulation of phenolic compounds in pak choi and swiss chard

Phenolic compounds are known for their health-promoting effects on humans. Pak choi (Brassica rapa ssp. chinensis) and Swiss chard (Beta vulgaris subsp. vulgaris) are used here as model plants, as they are eaten raw as baby leaf lettuce and differ in their phenolic compound profile while showing similar morphology. In a greenhouse an artificial light source with UV-B (215 mW m−2), blue (104 μmol/m−2 s−1) and red (245 μmol/m−2 s−1) LEDs was implemented to increase phenolic compounds during the last days before harvest. Pak choi shows an increase or trend towards an increase in the monoacylated triglycosides of kaempferol and quercetin after 4 days of irradiation for 4 h each. For example kaempferol-3-caffeoyl-sophoroside-7-glucoside was increased at low PAR values in the third run and red-dominated light treatment by up to 120 %. In addition, it was observed that the red variety ‘Amur’ has higher concentrations of quercetin glycosides which were increased often. In swiss chard, on the other hand, there was only a sporadic increase in vitexin glycosides. Despite very different concentrations in some samples, 2″-glucosyl-vitexin and 2′′-glucosyl-6′′-malonyl-vitexin showed significant increases of up to 350 % in the two chard varieties Lukullus and Rhubarb chard. The results suggest that the exposure time or intensity of UV-B radiation needs to be optimized for each species and has not yet consistently led to an increase but trends in phenolic compounds and in antioxidant activity in this study.

Flower-like layered ZnO nanoflakes for cost-effective visible light-assisted photodynamic oxidation of tetracycline and bacterial disinfection

The conventional precipitation method was employed to synthesize the flower-like layered ZnO nano-flakes, characterized, and their photocatalytic potential was investigated for control of tetracycline antibiotics and high-strength pathogenic bacteria in wastewater effluent. Scanning electron microscope measurements confirm the formation of flower-like nano-flakes. Under white light, the catalytic efficiency of the ZnO nano-flakes is higher compared to blue light for the photocatalytic degradation of tetracycline, the inactivation of multidrug-resistant bacteria, and total coliforms. Under white light irradiation with the intensity of 80 mW/cm2, the ZnO nano-flakes showed the highest tetracycline degradation efficacy of 86 % within 120 min and complete inactivation of bacteria within 90 min without any additional oxygen sources. Scavenging experiments have clarified the photocatalytic mechanism of the degradation of tetracycline. The used catalyst was simply recovered by centrifugation (5 min) and could be reused without significant loss of photocatalytic activity. The remarkable efficiency and stability of the ZnO nano-flakes in this study mark a distinct approach to the development of heterogeneous photocatalysts for pollutant degradation. To evaluate the feasibility of a photocatalytic process for achieving consistent disinfection, microbial inactivation experiments were conducted using a batch-scale photocatalytic reactor with blue and white LEDs. The study targeted high-strength multidrug-resistant bacteria, including E. coli (Gram-negative) and S. aureus (Gram-positive), as well as total coliform in secondary effluent. This research clarifies the practical potential of ZnO nano-flakes for cost-effective photocatalytic oxidation treatment of wastewater pollutants.

Red-emitting phosphors NaLiXF6:Mn4+ (X = Ti, Si) for white LEDs with high color rendering index and low correlated color temperature

White light-emitting diodes (WLEDs) are widely used in various lighting applications due to their high brightness and energy efficiency. However, commercial WLEDs, which typically combine YAG:Ce3+ phosphors with blue light-emitting diode chips, often lack red components, resulting in a high correlated color temperature (CCT) and a low color rendering index (CRI). To address this issue, two novel Mn4+-doped red-emitting phosphors, NaLiTiF6 and NaLiSiF6, were synthesized using an ion exchange method. Both phosphors exhibit strong red light with a pronounced zero-phonon line (ZPL) emission under blue light excitation. Optimal photoluminescence emission intensities were observed at Mn4+ concentrations of 6% for NaLiTiF6 and 9% for NaLiSiF6. When the temperature increased from 303 K to 413 K, both phosphors demonstrated outstanding brightness and chromatic stability. Integrated into phosphor-converted light-emitting diodes (pc-LEDs), the device incorporating NaLiTiF6:6%Mn4+ achieved a CRI of 95.1 and a CCT of 3172 K, while the device with NaLiSiF6:9%Mn4+ showed a CRI of 87.9 and a CCT of 3784 K. In addition, the luminous efficacy, CRI, and CCT of both prototype pc-LEDs maintained minimal variation with increasing driving current. These results indicate the stability and suitability of the synthesized phosphors for enhancing the performance of warm WLEDs applications.

Optimum blue light exposure: a means to increase cell-specific productivity in Chinese hamster ovary cells

Research for biopharmaceutical production processes with mammalian cells steadily aims to enhance the cell-specific productivity as a means for optimizing total productivities of bioreactors. Whereas current technologies such as pH, temperature, and osmolality shift require modifications of the cultivation medium, the use of optogenetic switches in recombinant producer cells might be a promising contact-free alternative. However, the proper application of optogenetically engineered cells requires a detailed understanding of basic cellular responses of cells that do not yet contain the optogenetic switches. The knowhow of ideal light exposure to enable the optimum use of related approaches is missing so far. Consequently, the current study set out to find optimum conditions for IgG1 producing Chinese hamster ovary (CHO) cells which were exposed to blue LED light. Growth characteristics, cell-specific productivity using enzyme-linked immunosorbent assay, as well as cell cycle distribution using flow cytometry were analyzed. Whereas too harsh light exposure causes detrimental growth effects that could be compensated with antioxidants, a surprising boost of cell-specific productivity by 57% occurred at optimum high light doses. The increase coincided with an increased number of cells in the G1 phase of the cell cycle after 72 h of illumination. The results present a promising new approach to boost biopharmaceutical productivity of mammalian cells simply by proper light exposure without any further optogenetic engineering.Key points• Blue LED light hinders growth in CHO DP-12 cells• Antioxidants protect to a certain degree from blue light effects• Illumination with blue LED light raises cell-specific productivity

In situ growth of bismuth oxybromide/bismuth molybdate 2D/2D Z-scheme heterojunctions with rich interfacial oxygen vacancies for photocatalytic benzylic C(sp3)-H bond activation

The selective oxidation of toluene into valuable chemicals via photocatalytic C(sp3)-H bond activation represents a significant, yet challenging process. Here, the in situ construction of bismuth oxybromide/bismuth molybdate (BiOBr/Bi2MoO6) 2D/2D Z-scheme heterojunctions featuring interface-induced oxygen vacancies (OVs) is introduced. The optimized BiOBr/Bi2MoO6 sample has a remarkable yield rate of benzaldehyde at 2134.28 μmol g−1 h−1 under blue LED irradiation, surpassing the performance of BiOBr and Bi2MoO6 by 8.1 and 2.9 times, respectively. Insights from density functional theory (DFT) calculations, electron paramagnetic resonance (EPR), and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies highlight the critical role of the Z-scheme electronic configuration and OVs in attaining the superior photocatalytic toluene conversion efficiency. This study advances the photocatalytic conversion of benzaldehyde within an OV-enhanced direct Z-scheme system, facilitating the activation of inert C(sp3)-H bonds, and contributes to the development of high-performance catalysts for sustainable chemical processes.

Dielectric, structural and optical properties of lead-free Ba4(Dy2-xBix)Fe2Nb8O30 ferroelectrics

ABSTRACT A series of novel lead-free tungsten bronze-structured Ba4(Dy2-xBix)Fe2Nb8O30 (x = 0, 0.05, 0.1, 0.15, 0.2 and 0.25) were formulated by the traditional high-temperature solid-state method using ball milling for 30 hrs and calcined at 1115°C. The structural property was investigated using X-ray diffraction and Fourier transform infrared spectroscopy. The tetragonal structure with the P4bm space group was confirmed from Rietveld analysis. The scanning electron micrograph shows a uniform distribution of different-shaped grains with less porosity. The UV-vis analysis shows that the materials have band gaps in the range of 2.45–2.51 eV which makes them useful for photocatalytic applications. From photoluminescence analysis, it is confirmed that the samples can be used as violate-/blue light-emitting diodes. The impedance of the materials falls off with the rise in temperature showing their negative temperature coefficient behaviour. The variation of polarization with an electric field confirms the ferroelectric nature of the samples.

Synergetic effect driven LaMnO3@NiO composite based high energy semi-solid supercapacitor

Perovskite materials have gained substantial attention in last two decades as electrode materials for energy storage devices due to low cost, good electrochemical stability, mixed ionic-electronic conductivity, long-term stability, and environmentally friendly. We demonstrate the hybridization of lanthanum manganite (LaMnO3) and Nickel oxide (NiO) composite electrodes for supercapacitor application prepared via sol-gel assisted hydrothermal method. The structural, morphological, surface area, and elemental analysis has been done by X-ray diffraction, Field emission scanning electron microscopy, Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS) analysis. The structural, and morphological analysis confirmed the composite formation. The electrochemical properties have been examined by cyclic voltammetry, galvanostatic charge-discharge, and impedance analysis. The resulting LaMnO3/NiO composite material exhibits enhanced electrochemical performance compared to the individual components. The composite exhibits a specific capacitance of up to 170 F/g at a scan rate of 10 mV/s, which is higher than that of individual LaMnO3 or NiO materials. The composite also demonstrates desirable cycling stability, with a capacity retention of 76 % after 5000 cycles. These results advocate that the LaMnO3/NiO composite is a promising material for high-energy supercapacitor applications. Further performance of the nano-composite was evaluated by LED testing. Three symmetric SCs of the composite linked in series were able to glow a green, red, blue LED for about 1 min and a panel of 26 red LED was illuminated for about 12 min. These findings suggested that the obtained composite material is an exceptional electrode with huge potential for potential for supercapacitor application.

Light‐Induced Tetrafluoroethylation/Cyclization of N‐Methacryloyl‐2‐phenylbenzoimidazoles with 1,2‐Dibromotetrafluoroethane

Various N‐methacryloyl‐2‐arylbenzoimidazoles react with 1,2‐dibromotetrafluoroethane in the presence of photocatalyst 4CzIPN irradiated by 10 W blue LED to provide 5‐(3‐bromo‐2,2,3,3‐tetrafluoropropyl)‐5‐methylbenzo[4,5]‐imidazo[2,1‐a]isoquinolin‐6(5H)‐ones in good yield. The reaction proceeds through a sequential tetrafluoroethyl radical addition/cyclization pathway. The wide substrate scope, good functional group tolerance, and ease of scale‐up of this protocol are expected to promote its potential applications in pharmacy.

Fabrication of MnCo2O4@PANI nanocomposites as electrode material for high-energy density asymmetric supercapacitor

In this work, the co-precipitation method has been utilized to synthesize MnCo2O4 (MCO) and MnCo2O4@Polyaniline (PMCO) nanocomposites. The wt% of polyaniline (PANI) has been varied from 0 to 30 %, keeping the MnCo2O4 precursor quantity constant. The nanocomposite with 20 wt% PANI (P20MCO) exhibits better electrochemical properties compared to other synthesized nanocomposite samples. The P20MCO nanocomposite exhibits specific capacitances of 765 F g−1 at 0.5 A g−1 and 88.13 % capacitance retention over 10,000 consecutive cycles. An asymmetric supercapacitor (ASC) has been constructed using P20MCO as cathode and commercially activated carbon as anode. The fabricated ASC device exhibits outstanding cycling stability with 91.48 % capacitance retention for 45,000 cycles at 12 A g−1. The ASC has the highest power density of 14.3 kW kg−1 and specific energy density of 58 Wh kg−1. Moreover, a red LED is illuminated by a single device and putting two devices in series light the blue, green, and white LEDs. These ASCs glow a red LED for more than 13 min. Our results suggest that the P20MCO nanocomposite-based supercapacitor devices will be promising for energy storage applications because of their easy production approach and good electrochemical performance.

Conditions for thermally stable color characteristics of trichromatic white light-emitting diodes

We present a method to stabilize color characteristics from a trichromatic white light-emitting diode (LED) consisting of red, green, and blue (RGB) LEDs under varying ambient temperatures. Through colorimetric analyses, it was found that the trichromatic white LED could maintain its chromaticity coordinate by adjusting the light output power (LOP) of green and red LEDs as the temperature varied. Moreover, the correlated color temperature (CCT) could be invariant to the external temperature change by controlling only the LOP of a red LED. Using the developed mathematical model and temperature-dependent spectral data of commercial RGB LED samples, we determined the power ratios between RGB LEDs needed to achieve thermally stable color coordinates or CCT as the heat sink temperature varied from 20 to 100 °C. When operating under thermally stable CCT conditions, the chromaticity coordinate of the trichromatic LED moved along the iso-CCT line with only a minor color deviation as the temperature increased to 100 °C. The presented approach requires adjusting the power of only one LED to achieve thermally stable CCT operation in a trichromatic white LED, which is expected to simplify LED control circuits significantly.

Waste-to-resource strategy through green synthesis of PET-derived metal-organic frameworks for efficient photocatalytic dye degradation

Wastewater contaminated with dyes poses significant environmental and health hazards, including oxygen depletion and carcinogenesis. Photocatalytic technology offers a sustainable and efficient solution by harnessing abundant solar energy to drive chemical reactions, making it a cost-effective method for water treatment. Metal-Organic Frameworks (MOFs), known for their high surface area, porosity, and chemical tunability, are particularly promising materials for such applications. In this study, we developed a green synthesis method to repurpose polyethylene terephthalate (PET) bottles into terephthalic acid, which was then used to synthesize PET-MIL-101(Cr) (denoted as PM-101(Cr)). The synthesis process avoids the use of organic solvents such as HF or DMF to prevent secondary pollution. Further modification of PM-101(Cr) through nitration produced PET-NO2-MIL-101(Cr) (PO-101(Cr)), which was subsequently reduced to form amine-functionalized PET-NH2-MIL-101(Cr) (PH-101(Cr)). PH-101(Cr) demonstrated a dye removal efficiency of over 95 % within 4 h of blue light irradiation, surpassing the performance of PM-101(Cr). Additionally, after four catalytic cycles, PH-101(Cr) maintained a reduction efficiency above 95 % for 6 h, indicating its robust potential for effective dye treatment. In summary, PH-101(Cr) efficiently degrades methylene blue dye under blue LED light, achieving both waste recycling and environmental remediation for improved sustainability.

A novel pendulum-like deformation-limited piezoelectric vibration energy harvester triggered indirectly via a smoothly plucked drive plate

Vibration energy harvesting using the piezoelectric effect is emerging as a promising sustainable energy solution for micro-electromechanical systems and wireless sensor networks. Nevertheless, the advancement of piezoelectric vibration energy harvesters has been hindered by reliability issues stemming from piezoelectric material damage due to excessive deformation. To address this challenge, a pendulum-like deformation-limited piezoelectric vibration energy harvester triggered indirectly via a smoothly plucked drive plate (D-LPVEH) is proposed. The D-LPVEH effectively constrains the maximum deformation of the piezoelectric beam, enabling unidirectional deformation and enhancing reliability even under unexpected impacts, by introducing a drive plate. Simulation and experimental findings both validate the efficacy of limiting the piezoelectric beam’s deformation by integrating the drive plate structure. Besides, the D-LPVEH has a good environmental adaptability and designability, which means D-LPVEH can work in different frequency ranges by adjusting proof mass and mass arm length, even at low frequency environmental vibrations of a few Hertz. Moreover, the D-LPVEH demonstrates a peak output power of 0.77 mW at a mere 5.6 Hz, with an optimal load resistance of 100 kΩ, and can consecutively illuminate a minimum of 100 commercial blue LEDs. The D-LPVEH has demonstrated to have good power generation and high reliability. This design will provide a reference for the research on improving the reliability of PVEH.