Tin Oxide Surface Research Articles

Vibrational Spectroscopy Analysis of Oligothiophene Blend Film

One of the challenges in fabricating organic semiconductor thin film is to produce bettermolecular ordering that compromise its electronic properties. Molecular ordering of amorphous thin film can be improved in many ways. Here, high molecular weight polylactic acid (PLA) is introduced as binding matrix to promote 3'''-didodecyl-2,2':5',2'':5'',2'''-quaterthiophene (4T) film’s homogeinity across indium tin oxide (ITO) surface. Molecular ordering of the spin coated biodegradable PLA and 4T blend film processed at ambient atmosphere was studied using two vibrational spectroscopy methods. The complementary analysis of infrared absorption spectrum and Raman spectrum had identified several vibrational modes contributed by thiophene rings and alkyl functional groups. The Raman analysis implied there is a slight change of thiophene ringsʼ molecular orientation due to compressive stress after introduction of polymer. Microscopic characteristics of oligothiophenes especially at the π-π conjugated backbones contained crucial information in order to exploit the oligothiophene as flexible electronics devices.

Electrodeposition of Fe-Complexes on Oxide Surfaces for Efficient OER Catalysis

Progress in non-covalent/self-assembled immobilization methods on (photo)electrode materials for molecular catalysts could broaden the scope of attainable systems. While covalent linkage (though considered more stable) necessitates functional groups introduced by means of often cumbersome synthetic procedures, non-covalent assemblies require sufficient propensity of the molecular unit for surface adsorption, thus set less rigorous pre-requisites. Herein, we report efficient electrodeposition (ED) of two Fe(III) complexes prepared with closely related NN’N pincer ligands yielding stable and active ad-layers for the electrocatalysis of the oxygen-evolving reaction (OER). The ED method is based on the utilization of a chloride precursor complex [FeIIICl2(NN’N)], which is dissolved in an organic electrolyte undergoes chloride/aqua ligand exchange upon addition of water. ED provides patchy distribution of a chloride-depleted catalyst layer on indium tin oxide (ITO) and fluorine-doped tin oxide (FTO) surfaces, which can be applied for long periods as OER electrocatalysts. Compared to drop-casting or layering of [FeIIICl2(NN’N)] with Nafion (a commonly used support for molecular electrocatalysts), the surface modification by ED is a material saving and efficient method to immobilize catalysts.

Independently tunable double Fano-like resonances arising from the interference coupling of localized surface plasmons with waveguide modes

Research on the classical analogy of asymmetric Fano resonances has gained momentum in recent years, owing to the steep dispersion of the Fano-like profile in classical systems, such as plasmonic nanostructures and metamaterials, which has numerous applications. We studied the double Fano-like resonances arising in a waveguide structure made of a periodic array of gold nanospheres placed on the top surface of an indium tin oxide (ITO) film, which is deposited on a silica substrate. These resonances emanate from the interference coupling between the dipolar surface plasmon mode of the individual gold nanospheres and the zero-order transverse electric (TE) and transverse magnetic (TM) waveguide modes within the ITO film. Increasing the array period of the gold nanospheres or thickness of the ITO film shifted the resonance peaks towards the low-frequency side corresponding to the excitation frequencies of the zero-order TE and TM waveguide modes, which were red-shifted. Additionally, the double Fano-like resonance profiles were approximated using an analytical Fano interference model.

Large-area uniform Ag nanostructure films prepared by a heat reduction method for SERS application

We prepared an active large-area uniform Ag nanostructure film by using the thermally reducing polyvinyl alcohol (PVA)/silver nitrate (AgNO3) composite film for surface-enhanced Raman scattering (SERS) application. The PVA/AgNO3 composite films were spin-coated on the surface of indium tin oxide (ITO) glass, and then were heated to about 500 °C for 10 minutes, forming Ag nanostructure films with a thickness of 100 nm and a large area of 3.24 cm2. The results showed that single layer Ag nano-film had a network structure with a skeleton distribution. Moreover, the large ratio of Ag nanostructure to film area was about 63%. Using melamine molecules as a probe, the maximum enhancement factor of the SERS signal could reach 1149, and the SERS sensitivity and the minimum detection limit were respectively up to 76.91 and 3.85 ng/ml. This method of preparing SERS film can provide a new pathway for the application of low-cost and large-area SERS substrates.

Electrochemical and spectroscopic characterization of a new polymer based on eriochrome black T doped by carbon nanotubes

An electropolymerized film of new eriochrome black T (EBT) doped with carbon nanotubes (CNTs) has been prepared on the surface of indium tin oxide (ITO) in a solution of acetonitrile containing lithium perchlorate (LiClO4) as supporting electrolyte by cyclic voltammetry (CV). The distribution of CNTs in the poly eriochrome black T (PEBT) matrix was studied through scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy. Their chemistry and electrical properties were determined by CV and electrochemical impedance spectroscopy (EIS). The optical characterization of the composites was made by UV–Vis absorption. The results showed that CNTs nanoparticles were dispersed and co-deposited into the PEBT matrix; the voltammogram of EBT before and after doping with the semiconductor of CNTs present a large difference in the form of recorded cyclic voltammograms. It is noticed that the shape (intensity, potential and number of redox couple) of the cyclic voltamperogram varies with the addition of CNTs; the appearance of new peaks of oxidation and reduction suggests the formation of a new composite material. This confirmed that there is a reaction which develops between the EBT, CNTs and LiClO4. The best distinction of the peaks was obtained during the addition of 0.2 mg of CNTs, leading to increase the conductivity of the PEBT film that forms on the ITO electrode. The images of SEM confirm the presence of CNTs in the composite, which consequently modifies significantly the morphology of the film. The CV study showed redox couples characteristic of poly EBT at 0.6 and 0.5 V. The EIS measurements show that the resistance of the PEBT films decreases with increasing of CNTs amounts. This demonstrates that the inclusion of the CNTs enhance the electrical properties of the polymer. Thus, these composite films can be used in various fields. The optical bandgap decreased generally with increase in content of CNTs compared with PEBT only. This is explained by the introduction of the donor levels in the bandgap of PEBT by the CNTs, this decrease in gap energy is explained by the Burstein–Moss effect.

Oxygen Reduction Reaction in Layer-by-Layer Fabricated Cobalt Porphyrin-Based Nanostructures

Metalloporphyrin-based nanostructures were fabricated on 3-aminopropylmethoxysilane-modified indium tin oxide (ITO) surface. UV-visible spectroscopy and cyclic voltammetry are used for investigating electronic absorption spectra and catalytic activity in oxygen reduction reactions as alternative cathode electrochemical catalysts for polymer electrolyte membrane fuel cells (PEMFCs). Using of 5,10,15,20-tetrakis-(4-amiophenyl)-porphyrin-Co (II) as a building block and 1,4-phenylene diisocyanate as a linker, the mixed toluene/chloroform solution-based layer-by-layer process can produce linear growth of 5,10,15,20-tetrakis-(4-amiophenyl)-porphyrin-Co (II) up to 30 layers through urea bonds. The vacuum thermal annealing process demonstrated the improvement of catalytic activity in oxygen reduction reaction.

Electrochemical and surface enhanced infrared absorption spectroscopy studies of TEMPO self-assembled monolayers

The electron transfer kinetics of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) monolayers have been studied using both a chronocoloumetric method and surface sensitive infrared spectroelectrochemistry (attenuated total reflection surface enhanced infrared absorption spectroscopy, ATR-SEIRAS). Redox active self-assembled monolayers (SAMs) are constructed by covalently attaching 4-amino-TEMPO to preformed monolayers of different chain length alkanoic acid thiol monolayers. The density of TEMPO groups on the resulting Cn-TEMPO (n = 6, 8, 11, 12, 16) SAMs is approximately 20% of a full monolayer coverage and the resulting SAMs exhibit very little kinetic heterogeneity. Standard heterogeneous rate constants are measured as a function of SAM chain length. Tafel plots constructed for n = 12 show asymmetry between the forward (oxidation of the radical to the nitrosonium cation) and reverse (reduction to the TEMPO radical) reactions. The reorganization energy of the nitrosonium cation is estimated to be 1.0 ± 0.1 eV for the C16-TEMPO SAM. ATR-SEIRAS studies reveal that the oxidation of the TEMPO radical leads to a conformational change (chair-chair flip) in the piperdinyl ring. The nitrosonium conformer pushes the N=O+ center away from the electrode and into a polar environment. Conformational differences in the reduced and oxidized species are cited as the reason for kinetic asymmetry in the TEMPO/TEMPO+ redox system. Time-resolved ATR-SEIRAS is used to extract the standard rate constant for C12-TEMPO on gold island films deposited on an indium tin oxide (ITO) surface. Standard rate constants for SAMs formed on Au@ITO are found to be higher than those formed on gold beads due to greater kinetic heterogeneity caused by the larger roughness of the gold islands.

Direct Observation of the Light-Induced Exfoliation of Molybdenum Disulfide Sheets in Water Medium.

Single and a few atomic-layer molybdenum disulfide (MoS2) is a promising material in the fields of hydrogen generation, battery, supercapacitor, and environmental protection, owing to the outstanding electronic, optical, and catalytic properties. Although many approaches have been developed for exfoliation of MoS2 sheets, it is still essential to develop simple, convenient, and environmental friendly exfoliation methods. More importantly, the microscopic exfoliation process and the mechanism are still not clear, limiting a deeper understanding of the exfoliation. Herein, we develop a convenient and clean method for exfoliation of the 2H phase MoS2 (2H-MoS2) deposited on an indium tin oxide (ITO) surface. Importantly, the exfoliation process is observed directly and continuously under an optical microscope to reveal the detailed exfoliation process and mechanism. As illustrated, the light illumination triggers the exfoliation of the 2H-MoS2 sheets, and the presence of water is essential in this exfoliation process. The light intensity and wavelength, humidity, and bias all affect the exfoliation process obviously. The exfoliation is caused by the vaporization of the water molecules intercalated in 2H-MoS2 interlayers. By using this method, 2H-MoS2 nanosheets with different thicknesses are prepared on the ITO substrate, and microscopic catalysis mapping of the exfoliated sheets is demonstrated with single-molecule fluorescence microscopy, revealing that the prepared thin-layer 2H-MoS2 nanosheets show improved electrocatalysis activity (roughly 20 times). Our work will not only help deepen the understanding of exfoliation process of two-dimensional nanosheets but also provide an effective tool for the in situ study of various properties of the exfoliated sheets.

Mesoporous MnCo2O4, NiCo2O4, and ZnCo2O4 Thin-Film Electrodes as Electrocatalysts for the Oxygen Evolution Reaction in Alkaline Solutions

The oxygen evolution reaction (OER) is the bottleneck of the electrochemical water-splitting process, where the use of porous metal oxide electrodes is beneficial. In this work, we introduce a one-pot synthesis method to fabricate a series of mesoporous metal cobaltite (m-MCo2O4, M = Mn, Ni, and Zn) electrodes for the OER. The method involves preparation and coating of a homogeneous clear solution of all ingredients (metal salts and surfactants) over a fluorine-doped tin oxide surface as a thin lyotropic liquid crystalline film and calcination (as low as 250 °C) to obtain a 400 nm thick crystalline m-MCo2O4 electrode with a spinel structure. Mesophases and m-MCo2O4 films are characterized using structural and electrochemical techniques. All electrodes are stable during the electrochemical test in 1 M KOH aqueous solution and perform at as low as 204 mV overpotential at 1 mA/cm2 current density; the m-MnCo2O4 electrode works at current densities of 1, 10, and 100 mA/cm2 at 227, 300, and 383 mV overpotentials after compensating the IR drop, respectively. The Tafel slope is 60 mV/dec for the m-NiCo2O4 and m-ZnCo2O4 electrodes, but it gradually increases to 85 mV/dec in the m-MnCo2O4 electrode by thermal treatment, indicating a change in the OER mechanism.

Detection of Kallikrein-Related Peptidase 4 with a Label-free Electrochemical Impedance Biosensor Based on a Zinc(II) Phthalocyanine Tetracarboxylic Acid-Functionalized Disposable Indium Tin Oxide Electrode.

A new impedimetric biosensing system based on kallikrein-related peptidase 4 (KLK 4) antigen-specific antibodies and a zinc(II) phthalocyanine tetracarboxylic acid (Zn-PcTCa) matrix material was developed for the first time in this study. First, a Zn-PcTCa-coated indium tin oxide surface was used as an interface matrix material for the immobilization of anti-KLK 4 antibodies, and they bound to the platform via amide bonds. In the presence of KLK 4 antigens, the anti-KLK 4 antibodies specifically captured these antigens and caused changes in the electrochemical properties of the system. Randles equivalent circuit was utilized to evaluate the impedimetric signal, which was measured with the help of an electrochemical impedance spectroscopy method. After the specific interaction, the electron transfer resistance (Rct) was remarkably increased and displayed a linear relationship with the level of the KLK 4 antigen in the range of 0.02-15 pg/mL, with a a detection limit of 6.8 fg/mL. The designed biosensor was able to detect a KLK 4 antigen with good sensitivity, excellent specificity, and high stability. In addition, because of having a low-cost and robust procedure for fabrication, it could be repeatedly used in several areas including clinical diagnosis.

Catalysis on Nanostructured Indium Tin Oxide Surface for Fast and Inexpensive Probing of Antibodies during Pandemics

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global threat to human health and the economy. Society needs inexpensive, fast, and accurate quantitative diagnostic tools. Here, we report a new approach using a solid-state biosensor to measure antibodies, which does not require functionalization, unlike conventional biosensors. A nanostructured semiconductor surface with catalytic properties was used as a transducer for rapid immobilization and measurement of the antibody. The transducer response was based on solid-state electronics properties. The changes on the surface of the semiconductor induced changes in the direct current (DC) surface resistivity. This was a result of a catalytic chemical reaction on that surface. This new low-cost approach reduced the response time of the measurement significantly, and it required only a very small amount of sample on the microliter scale.

Stability of the structure and redox state of ferricytochrome c in the desolvation process

Stability of the structure and redox state of ferricytochrome c during continuous changing of the hydration environment from dilute solution to condensed phase was studied based on real-time resonance Raman measurement. Our experimental results indicated that the structure and redox state of ferricytochrome c were sufficiently maintained during the entire desolvation process, which reflected that the stabilizing excluded-volume effect was stronger than the destabilizing crowder-protein interaction, at the case of globular mini-protein itself acting as the crowder. Rapid reduction of ferricytochrome c was observed at measurement sites at the time of solution to condensed phase transition. Similar phenomenon was observed on cytochrome c adsorbed on indium tin oxide surface. At present conditions, the rapid reduction was found to be derived mainly from thermal reduction under laser illumination and secondarily from photoreduction induced by the residual adsorbed ferrocyanide anions. After re-dissolved, the protein which had undergone sufficient desolvation recovered the structure and redox state in the initial solution phase, suggesting that the crowding effect in solution prevented large protein deformations observed in gas phase condition.

Charge-Induced Birefringence in a Room-Temperature Ionic Liquid.

We have reported previously on the existence of a surface charge-induced free charge density gradient (ρf) in room-temperature ionic liquids (RTILs) with a characteristic persistence length of ca. 50 μm [Ma, K. Langmuir 2016, 32, 9507-9512]. The free charge density gradient is related to the dielectric response of the RTIL. We report here on the existence of a surface charge-induced gradient in the RTIL refractive index and quantify the relationship between the index gradient and ρf. Because ρf is uniaxial, the induced refractive index gradient is manifested as an induced birefringence. The RTIL sample holder has a curved surface such that the RTIL can function as a lens, and ρf is controlled by the surface charge density (σs) of the (concave) RTIL support. Current passed through an indium-doped tin oxide (ITO) surface layer on the support surface controls σs. The far-field image of light passed through the RTIL lens as a function of σs is used to measure the charge-induced changes of n in the RTIL. We demonstrate a modulation of the refractive index on the order of 15%, proportional to σs. This report places the relationship between ρf and RTIL dielectric response on a quantitative footing and suggests the utility of RTILs for electro-optic applications.

Development of a molecularly imprinted photoelectrochemical sensing platform based on NH2-MIL-125(Ti)–TiO2 composite for the sensitive and selective determination of oxtetracycline

In this work, a molecularly imprinted photoelectrochemical (MIP-PEC) sensor based on a novel PEC composite of metal-organic frameworks (MOFs) and TiO2 (NH2-MIL-125(Ti)–TiO2) was established for the ultrasensitive and selective detection of oxytetracycline (OTC). This is the first attempt of applying MOFs in the construction of MIP-PEC sensor. The NH2-MIL-125(Ti)–TiO2 was synthesized by a simple one-step solvothermal method and modified onto the surface of indium tin oxide (ITO) electrode as the photosensitive layer. Subsequently, molecularly imprinted polymer (MIP) was modified as recognition element by electropolymerization. The NH2-MIL-125(Ti)–TiO2 showed an enhanced photocurrent response due to stronger light absorption capacity and matched energy band. Furthermore, MIP greatly improved the selectivity and sensitivity of the constructed PEC sensor. The photocurrent response of the MIP-PEC sensor was reduced after OTC recognition because the specific binding of OTC to the imprinted cavities blocked the electron transfer of the electrode. Under optimal experimental conditions, the MIP-PEC sensor exhibited a wide detection range from 0.1 nM to 10 μM with a low limit of detection (LOD) of 60 pM, as well as certain reproducibility, stability and good applicability in real samples. The proposed sensor provides ideas for the application of MOFs in the construction of PEC sensors and will offer an alternative method for the detection of other pollutants in the field of food safety.

Evaluation of Indium Tin Oxide for Gas Sensing Applications: Adsorption/Desorption and Electrical Conductivity Studies on Powders and Thick Films.

By combining results of adsorption/desorption measurements on powders and electrical conductivity studies on thick and thin films, the interaction of indium tin oxide with various ambient gas species and carbon monoxide as potential target gas was studied between room temperature and 700 °C. The results show that the indium tin oxide surfaces exhibit a significant coverage of water-related and carbonaceous adsorbates even at temperatures as high as 600 °C. Specifically carbonaceous species, which are also produced under carbon monoxide exposure, show a detrimental effect on oxygen adsorption and may impair the film’s sensitivity to a variety of target gases if the material is used in gas sensing applications. Consequently, the operating temperature of an ITO based chemoresistive carbon monoxide sensor should be selected within a range where the decomposition and desorption of these species proceeds rapidly, while the surface oxygen coverage is still high enough to provide ample species for target gas interaction.

First-Principles Study of Epoxy Resin Adhesion to Tin Oxide Surface

A density functional theory (DFT) is used to investigate the energetics of an epoxy resin adhere on a tin oxide and a hydroxylated-alumina surface within a supercell approach. Self—consistent geometry optimization is performed for models of adhesion interface, which is comprised of a fragment of epoxy resin and hydroxylated-Al2O3 (001), and SnO2(001) and (110) surface. The epoxy resin studied was simplified fragment based on diglycidyl ether of bisphenol A (DGEBA). It is found that the distance between the resin and the surface where the adhesion force is maximized is substantially the same for all models. Analysis of the energy-distance plot reveals that the fragment of DGEBA molecule adhere most strongly to the SnO2(001) surface, suggesting that the adhesion force is induced by van der Waals (vdW) interaction.

Differences in ITO Interface Characteristics Change According to the Formation of Aromatic-Ring and Aliphatic Self-Assembled Monolayers

Herein, we confirm the performance difference according to the structure of self-assembling monolayer (SAM) and investigate the characteristics of the indium tin oxide (ITO) surface when ITO substrates are deposited by (3,3,3-trifluoropropyl)trimethoxysilane (F-3SAM) and (heptadecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane (F-10SAM) having different chain lengths with trifluoromethyl group as terminal functional group, as well as SAM benzoic acid (BA) and 2-naphthoic acid (NA) with benzene ring forms. Through these, it is possible to control the wetting properties, surface roughness, and work function of the ITO surface. Wetting characteristics, average roughness, and changes in work function of the ITO surface were characterized by contact angle measurement, atomic force microscopy (AFM), and UV photoelectron spectroscopy (UPS). The measured contact angles were 41.1°, 82.25°, and 118° for the bare ITO, NA, and F-10SAM, respectively, the average roughnesses of the SAM-modified surfaces were 1.377, 1.033, and 0.838 nm for the bare ITO, NA, and F-10SAM, respectively. The work function of the ITO surface modified with NA and F-10SAM increased from 0.21 and 0.36 eV to 5.01 and 5.16 eV, respectively. As a result, the surface properties of ITO were better for aliphatic SAM than for aromatic ring SAM.

Synthesis and Photovoltaics of Novel 2,3,4,5-Tetrathienylthiophene-co-poly(3-hexylthiophene-2,5-diyl) Donor Polymer for Organic Solar Cell.

This report focuses on the synthesis of novel 2,3,4,5-tetrathienylthiophene-co-poly(3-hexylthiophene-2,5-diyl) (TTT-co-P3HT) as a donor material for organic solar cells (OSCs). The properties of the synthesized TTT-co-P3HT were compared with those of poly(3-hexylthiophene-2,5-diyl (P3HT). The structure of TTT-co-P3HT was studied using nuclear magnetic resonance spectroscopy (NMR) and Fourier-transform infrared spectroscopy (FTIR). It was seen that TTT-co-P3HT possessed a broader electrochemical and optical band-gap as compared to P3HT. Cyclic voltammetry (CV) was used to determine lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energy gaps of TTT-co-P3HT and P3HT were found to be 2.19 and 1.97 eV, respectively. Photoluminescence revealed that TTT-co-P3HT:PC71BM have insufficient electron/hole separation and charge transfer when compared to P3HT:PC71BM. All devices were fabricated outside a glovebox. Power conversion efficiency (PCE) of 1.15% was obtained for P3HT:PC71BM device and 0.14% was obtained for TTT-co-P3HT:PC71BM device. Further studies were done on fabricated OSCs during this work using electrochemical methods. The studies revealed that the presence of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) on the surface of indium tin oxide (ITO) causes a reduction in cyclic voltammogram oxidation/reduction peak current and increases the charge transfer resistance in comparison with a bare ITO. We also examined the ITO/PEDOT:PSS electrode coated with TTT-co-P3HT:PC71BM, TTT-co-P3HT:PC71BM/ZnO, P3HT:PC71BM and P3HT:PC71BM/ZnO. The study revealed that PEDOT:PSS does not completely block electrons from active layer to reach the ITO electrode.

Enhanced electrochemiluminescence at single lithium iron phosphate nanoparticles for the local sensing of hydrogen peroxide efflux from single living cell under a low voltage

The pursuit of strong electrochemiluminescence (ECL) at a low voltage is crucial, but challenging, for further development of ECL based bioanalysis, especially at single cells. In this work, single lithium iron phosphate (LiFePO4, LFP) nanoparticles at the surface of indium tin oxide (ITO) is firstly applied to produce enhanced ECL from luminol and hydrogen peroxide under a low voltage of 0.5 V. Lithium ions from single LFP particles are proposed to be de-intercalated during the charging process and then inserted into ITO to form LiSnO2, in which the oxidation of a luminol derivative (L012) is promoted resulting in an ECL emission at a low voltage. Meanwhile, the transformation of LiFePO4 into FePO4 under this voltage accelerates the generation of oxygen intermediates from hydrogen peroxide, and thus, leads to an elevated ECL intensity. Eventually, the efflux of hydrogen peroxide from single living cells is directly visualized under a voltage of 0.5 V using the ECL imaging approach, which is significantly lower than the previous voltage of 1.0 V. The first coupling of lithium migration in ECL reaction will pave a new direction to improve the ECL emission efficiency, and ultimately, push the development of ECL technology in highly spatial sensing of single cells.

High polarization and fast modulation speed of dual wavelengths electroluminescence from semipolar (20-21) micro light-emitting diodes with indium tin oxide surface grating

We present highly polarized dual wavelength semipolar InGaN micro-light-emitting diodes (μLEDs) by combining an indium tin oxide (ITO) surface grating and Al-coated dual-color surface plasmons (DSPs). The ITO grating DSPs enable a significant enhancement of the polarization ratio (PR) from electrically driven semipolar (20-21) μLEDs with dual emission wavelengths: the overall PR was increased by 1.7-folds and the output power was enhanced by 78% as compared to the conventional semipolar μLEDs at an injection current density of 100 A/cm2. Moreover, a high 3 dB modulation bandwidth of 612 MHz is achieved at ∼1.4 kA/cm2 in a visible-light communication (VLC) system, suggesting a near 1.24 Gbit/s under a non-return-to-zero on-off keying modulation scheme. This design marks significant progress in developing polarized μLEDs with potential applications in various fields, such as displays and VLC.