Well-ordered Monolayers Research Articles

Machine Learning Aided Design and Optimization of Antifouling Surfaces.

Antifouling surfaces, renowned for their strong surface resistance to proteins, cells, or tissues in various biological and environmental conditions, have broad applications in implanted devices, antibacterial coatings, biosensors, responsive materials, water treatment, and lab-on-a-chip. While extensive experimental research exists on antifouling surfaces, machine learning studies on this topic are relatively few. This perspective specifically focuses on exploring the complex relationships between the composition, structure, and properties of antifouling surfaces, examining how these factors correlate with surface hydration and protein adsorption. Different machine learning models have been developed to analyze and predict single and multiple protein adsorptions on various types of surfaces, ranging from structureless surfaces to well-ordered and rigid self-assembled monolayers, dynamically ordered polymer brushes, and complex filtration membranes. These models not only identify key descriptors or functional groups critical for antifouling performance (surface hydration, protein adsorption) but also predict the antifouling properties for a specific surface. Recognizing current challenges, this perspective delineates future research directions in the antifouling field. By leveraging and comparing current machine learning approaches, it aims to advance both the design and fundamental understanding of antifouling surfaces, thereby pushing the boundaries of innovation in this critical field.

Directed Self-Assembly of Polystyrene-Block-Polyhedral Oligomeric Silsesquioxane Monolayer by Nano-Trench for Nanopatterning.

This work pioneers to combine fast self-assembly of polyhedral oligomeric silsesquioxanes (POSS) nanocage-based giant surfactants with high etching contrast and directed self-assembly for reliable long-range lateral order to create well-aligned sub-10nm line nanopatterns via reactive ion etching (RIE). Polystyrene-block-oligo(dimethylsiloxane) substituted POSS (PS-b-oDMS7POSS) with seven oligo(dimethylsiloxane) at the corners of the POSS nanocage and one polystyrene (PS) tail is designed and synthesized as a giant surfactant with self-assembly behaviors like block copolymer (BCP). In contrast to BCP, oDMS7POSS gives a volume-persistent "nanoatom" particle with higher mobility for fast self-assembly and higher segregation strength with PS for smaller feature size. By taking advantage of directed self-assembly using nano-trench fabricated by electron beam lithography, well-ordered nanostructured monolayer with well-aligned parallel oDMS7POSS cylinders can be formed by confined self-assembly within the nano-trench. With the optimization of the RIE treatment using O2 as an etchant, the high etching contrast from the oDMS7POSS and PS gives the formation of well-defined line nanopatterns with sub-10nm critical dimension that can serve as a mask for pattern transfer in lithography. These results demonstrate a cost-effective approach for nanopatterning by utilizing a creatively designed giant surfactant with sub-10nm feature size and excellent etching contrast for modern lithographic applications.

Enhancement of pH imaging of light addressable potentiometric sensor by colloidal spherical lens array

Visualizing the distribution of pH in a solution is an important basis for monitoring reaction processes and metabolic changes in micro-biochemical species. Light addressable potentiometric sensor (LAPS), as a simple structure, flexible imaging, low-cost and label-free electrochemical sensor, has been widely used to pH imaging. However, its spatiotemporal resolution is greatly affected by the frequency of modulation light, thus limiting its imaging performance. In this study, LAPS device modified by well-ordered and low-cost polystyrene (PS) colloidal monolayer as spherical lens array is proposed to obtain higher available modulation frequency of the maximum photoresponse. The morphology, optical properties and the electric field distribution of PS colloidal spherical lens array were tested and analyzed. pH sensing, imaging of uniform pH solution, the spatiotemporal pH imaging and dynamic imaging of enzymatic reactions of LAPS modified by PS colloidal spherical lens array were tested and evaluated. The experimental results show that LAPS modified by PS colloidal spherical lens array not only has acceptable pH sensing, but also widens the modulation frequency of the maximum photoresponse to 40 kHz. LAPS modified by colloidal spherical lens array modulated at the frequency of 40 kHz shows acceptable sensitivity and linearity, good reproducibility and stability, high SNR and high-spatiotemporal pH imaging capability. This work can be suitable for high-spatiotemporal monitoring of the changes in electrolyte environmental pH caused by the reaction and metabolism of the biochemical species.

Photoinduced Stitching of Self-Assembled Triangular Silver Nanoprisms at the Air-Water Interface.

This study investigates the influence of optical excitation on the self-assembly of triangular nanoprisms of silver into a continuous monolayer at the air-water interface. Langmuir monolayers of octadecylamine (ODA) have been used to electrostatically assemble citrate-capped silver triangular nanoprisms (AgTNPs) in the presence and absence of light. Under optical excitation, the nanoprisms were observed to assemble into a well-ordered monolayer through plasmon-mediated stitching, whereas the particles were merely in close contact during assembly in the dark. These findings suggest new avenues for tailoring particle properties through light-mediated assembly in two dimensions.

Ultrasensitive, label-free, electrochemical detection of miRNA-206 in human plasma: A potential biomarker associated with Alzheimer’s disease

An impedance-based biosensor for the ultrasensitive, selective, and label-free detection of a blood miRNA associated to Alzheimer disease (AD), miRNA-206, was developed. The principle was grounded in the changes in the charge transfer resistance (RCT) as an effect of intramolecular forces between miRNAs and ferro/ferricyanide in a well-structured transducer platform. A compact well-ordered mixed monolayer made of co-immobilized miRNA capture to 6-mercapto-1-hexanol (MCH) in a 1:4 M ratio (at 37 °C), uplifted the performance of the sensor through effectively assisting the orientation of the oligonucleotides. In this work, the remarkable response of the sensor was generated through new insights into the use of different moieties of miRNA capture to MCH, aiming to control interfacial constants, surface densities, and hybridization efficiency.A very low limit of detection, 0.15 aM, is achieved and the sensor has a wide linear dynamic range (from 1 aM to 1 μM), high selectivity to mismatches, low non-specific binding of proteins (BSA) and good stability (<10 % change in response after 14 days storage). Importantly, the sensor successfully measured miRNA-206 concentrations in real plasma samples (>95 % recovery), correlating directly with qPCR results. Nanomolar concentrations of miRNA-206 were found in the plasma of confirmed AD patients, while healthy controls, had a concentration of pM or lower. The biosensor's ability to quantitatively detect miRNA-206 in plasma without target amplification, e.g., using PCR, is significant, opening the possibility of developing a point-of-care diagnostic device for AD screening, contributing to clinical trials and patient care.

Massively Scalable Self-Assembly of Nano and Microparticle Monolayers via Aerosol Assisted Deposition.

An extremely rapid process for self-assembling well-ordered, nano, and microparticle monolayers via a novel aerosolized method is presented. The novel technique can reach monolayer self-assembly rates as high as 268 cm2 min-1 from a single aerosolizing source and methods to reach faster monolayer self-assembly rates are outlined. A new physical mechanism describing the self-assembly process is presented and new insights enabling high-efficiency nanoparticle monolayer self-assembly are developed. In addition, well-ordered monolayer arrays from particles of various sizes, surface functionality, and materials are fabricated. This new technique enables a 93× increase in monolayer self-assembly rates compared to the current state of the art and has the potential to provide an extremely low-cost option for submicron nanomanufacturing.

Electrochemistry of Redox Active Ferrocene Covalently Attached to Glassy Carbon Electrodes

Formation of well-ordered redox active monolayers is desirable for systematic study of electron transfer for sensor applications and generation of tailored hybrid materials. We have covalently attached 6-bromohexylferrocene (Fc(CH2)6Br) to glassy carbon electrodes through a Grignard reaction and used cyclic voltammetry to characterize interfacial electron transfer and probe disorder in these modified electrodes. X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry confirmed attachment of the expected Fe(II) species and reversible electron transfer is observed. However, the full width at half max of the cyclic voltammogram features deviates from the ideal value of 90.6 mV and varies with surface coverage, indicating a disordered surface. We determine this disorder arises from phase segregation where some domains have a high loading of the hexylferrocene chains while others have a lower loading of hexylferrocene resulting in different local environments that are distinguishable by cyclic voltammetry.

Molecular Orientations of Myristic Acid Derivatives with Different Perfluoroalkyl Chain Lengths at the Air/Water Interface Evaluated by Heterodyne-Detected Sum Frequency Generation Spectroscopy

Surface-related properties of perfluoroalkyl compounds such as hydrophobicity and adhesion force can have a close relationship with the orientational order of the molecules at the surface. Myristic acid (MA) derivatives with perfluoroalkyl (Rf) groups have been known to form a well-ordered monolayer at the air/gold substrate interface. In this study, molecular orientations of the MA derivative monolayers at the air/water interface were investigated by heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy. We estimated the molecular orientation of MA derivative monolayers with a marker band observed at around 1370 cm–1. The Rf chain length and the surface pressure dependence of the molecular orientation of four MA derivatives were examined. The marker bands were observed except for the derivative with the shortest Rf chain at the higher surface pressure, whereas the marker bands were observed only for the two derivatives with relatively longer Rf chain lengths at the lower surface pressure. The observation indicates that the longer the Rf chain is and the higher the surface pressure is, MA derivatives tend to adopt a standing orientation closer to perpendicular to the interface.

Self-Assembled Monolayer for Low-Power-Consumption, Long-Term-Stability, and High-Efficiency Quantum Dot Light-Emitting Diodes

Quantum dot light-emitting diodes (QLEDs) are an emerging class of optoelectronic devices with a wide range of applications. However, there still exist several drawbacks preventing their applications, including long-term stability, electron leakage, and large power consumption. To circumvent the difficulties, QLEDs based on a self-assembled hole transport layer (HTL) with reduced device complexity are proposed and demonstrated. The self-assembled HTL is prepared from poly[3-(6-carboxyhexyl)thiophene-2,5-diyl] (P3HT-COOH) solution in N,N-dimethylformamide (DMF) forming a well-ordered monolayer on an indium-tin-oxide (ITO) anode. The P3HT-COOH monolayer has a smaller HOMO band offset and a sufficiently large electron barrier with respect to the CdSe/ZnS quantum dot (QD) emission layer, and thus it is beneficial for hole injection into and electron leakage blocking from the QD layer. Interestingly, the QLEDs exhibit an excellent conversion efficiency (97%) in turning the injected electron-hole pairs into light emission. The performance of the resulting QLEDs possesses a low turn-on voltage of +1.2 V and a maximum external quantum efficiency of 25.19%, enabling low power consumption with high efficiency. Additionally, those QLEDs also exhibit excellent long-term stability without encapsulation with over 90% luminous intensity after 200 days and superior durability with over 70% luminous intensity after 2 h operation under the luminance of 1000 cd m-2. The outstanding device features of our proposed QLEDs, including low turn-on voltage, high efficiency, and long-term stability, can advance the development of QLEDs toward facile large-area mass production and cost-effectiveness.

Sterically crowded di-indazolyl-pyridines: Iron(II) complexation studies

Abstract 4-(2,6-Di(2H-indazol-2-yl)pyridin-4-yl)benzoic acid (1) and 10-(2,6-di(1H-pyrazol-1-yl)pyridin-4-yl)anthracene-9-carboxylic acid (2) were required for adsorption studies on Ag(111), with a view to subsequent iron(II) complexation and formation of well-ordered spin-responsive self-assembled monolayers. While the generation of these compounds has remained elusive, several intermediates and by-products were obtained, potentially useful as dipyrazolylpyridine-related derivatives and for metal ion coordination. 3,5-Dichloro-2,6-diindazolylpyridine-4-amine, which forms as a mixture of regioisomers, was synthesised, the mixture separated, and the components characterised (3,5-dichloro-2,6-di(2H-indazol-2-yl)pyridin-4-amine; 3,5-dichloro-2-(1H-indazol-1-yl)-6-(2H-indazol-2-yl)pyridin-4-amine; 3,5-dichloro-2,6-di(1H-indazol-1-yl)pyridin-4-amine). Their iron(II) complexes have been prepared and fully characterised, including single crystal X-ray structure determination. The complexes are instructive examples of the influence of ligand design (“steric jamming”) on the spin-crossover (SCO) activity of FeII centres. Bulky substitution, which entails twisted ligand conformation, increases intramolecular crowding. This prevents contraction of the metal coordination sphere, which would be a prerequisite for thermally inducible SCO. Mössbauer spectroscopy has revealed that the complexes remain predominantly high-spin (HS) between 20 and 200 K, and that a mixture of conformational HS isomers is present in the microcrystalline solid.

Long and oriented graphene nanoribbon synthesis from well-ordered 10,10'-dibromo-9,9'-bianthracene monolayer on crystalline Au surfaces.

Bottom-up synthesis on metal surfaces has attracted attention for the fabrication of graphene nanoribbons (GNRs) with atomically-precise chemical structures to realize novel electronic devices. However, control of length and orientation on surfaces during GNR synthesis is difficult, thus, achieving longer and aligned GNR growth is a significant challenge. Herein, we report GNR synthesis from a well-ordered dense monolayer on Au crystalline surfaces for long and oriented GNR growth. Scanning tunneling microscopy showed that 10,10'-dibromo-9,9'-bianthracene (DBBA) precursors deposited on Au(111) at room temperature self-assembled into a well-ordered dense monolayer, and the straight molecular wire structure was formed where Br atoms in each precursor were adjacent along the wire axis. The DBBAs in the monolayer were found to be hardly desorbed from the surface under subsequent heating and efficiently polymerize along with the molecular arrangement, resulting in more long and oriented GNR growth compared to the conventional growth method. The result is attributed to be suppression of random diffusion and desorption of the DBBAs on the Au surface during polymerization due to the densely-packed DBBA structure. Additionally, an investigation of the effect of the Au crystalline plane on the GNR growth revealed further anisotropic GNR growth on Au(100) compared to Au(111) due to the stronger interactions of DBBA with Au(100). These findings provide fundamental knowledge for controlling GNR growth from a well-ordered precursor monolayer to achieve more long and oriented GNRs.

Formation and structural characterization of two-dimensional wetting water layer on graphite (0001).

Understanding the structure and wettability of monolayer water is essential for revealing the mechanisms of nucleation, growth, and chemical reactivity at interfaces. We have investigated the wetting layer formation of water (ice) on the graphite (0001) surface using a combination of low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM). At around monolayer coverages, the LEED pattern showed a (2 × 2) periodicity and STM revealed a hydrogen-bonded hexagonal network. The lattice constant was about 9% larger than that for ice Ih/Ic crystals, and the packing density was 0.096 Å-2. These results indicate that an extended ice network is formed on graphite, different from that on metal surfaces. Graphite is hydrophobic under ambient conditions due to the airborne contaminant but is considered inherently hydrophilic for a clean surface. In this study, the hydrophilic nature of the clean surface has been investigated from a molecular viewpoint. The formation of a well-ordered commensurate monolayer supports that the interaction of water with graphite is not negligible so that a commensurate wetting layer is formed at the weak substrate-molecule interaction limit.

Cooperative Effect of Electron Spin Polarization in Chiral Molecules Studied with Non-Spin-Polarized Scanning Tunneling Microscopy.

Polyalanine molecules (PA) with an α-helix conformation have recently attracted a great deal of interest, as the propagation of electrons through the chiral backbone structure comes along with spin polarization of the transmitted electrons. By means of scanning tunneling microscopy and spectroscopy under ambient conditions, PA molecules adsorbed on surfaces of epitaxial magnetic Al2O3/Pt/Au/Co/Au nanostructures with perpendicular anisotropy were studied. Thereby, a correlation between the PA molecules ordering at the surface with the electron tunneling across this hybrid system as a function of the substrate magnetization orientation as well as the coverage density and helicity of the PA molecules was observed. The highest spin polarization values, P, were found for well-ordered self-assembled monolayers and with a defined chemical coupling of the molecules to the magnetic substrate surface, showing that the current-induced spin selectivity is a cooperative effect. Thereby, P deduced from the electron transmission along unoccupied molecular orbitals of the chiral molecules is larger as compared to values derived from the occupied molecular orbitals. Apparently, the larger orbital overlap results in a higher electron mobility, yielding a higher P value. By switching the magnetization direction of the Co layer, it was demonstrated that the non-spin-polarized STM can be used to study chiral molecules with a submolecular resolution, to detect properties of buried magnetic layers and to detect the spin polarization of the molecules from the change in the magnetoresistance of such hybrid structures.

Nonlinear Behavior during the Electrochemical Oxidation of Thiols

The electrochemical behavior of sulfur-containing compounds is of great importance in fields ranging from diagnostics to energy-storage and materials chemistry. For example, thiols (R-SH) are important components of many electrochemical sensors and are routinely used in materials applications as they are known to form well-ordered and reproducible monolayers (self-assembled monolayers, SAMs) on various metal surfaces. Sulfur compounds are also interesting from the viewpoint of nonlinear dynamics owing to the presence of multiple oxidation states, which has been exploited to study complex dynamic behavior in both chemical and electrochemical systems. In this work we explore the oscillatory behavior of 2-(dimethylamino)ethanethiol (DMAET), a known hydrolysis product of V-type nerve agents, on platinum electrodes. Interestingly, the electrochemical oxidation of DMAET leads to two distinct regions of oscillatory behavior. Probing the system with electrochemical impedance spectroscopy (EIS), resulted in the classification of the DMAET system as an HN-NDR type oscillator. These results are compared to structurally similar thiol containing compounds towards the goal of elucidating general features which permit the evolution of dynamic behavior in thiol-based electrochemical systems.

Impact of Adsorption of Straight Chain Alcohol Molecules on the Optical Properties of Calcite (10.4) Surface.

Calcium carbonate plays a central role in controlling the chemistry of the oceans, biomineralization and oil production, to name a few. In this work, using density functional theory with semiempirical dispersion corrections and simplified TD-DFT using Tamm–Dancoff approximation, we investigated the impact of the adsorption of straight chain alcohol (ethanol and pentanol) molecules on the optical properties of a calcite (10.4) surface. Our results show that ethanol and/or pentanol molecules form a well-ordered monolayer (through their hydroxyl group with carbon chains sticking away in a standing-up position) on the calcite (10.4) surface. Additionally, we found intriguing modulations in the photoabsorption spectra and circular dichroism spectra. In particular, the latter was a unique optical fingerprint for a molecule-adsorbed calcite (10.4) surface. Our findings provide useful insights into the structural and optical features of calcite-based systems at the atomic level.

Sub-5 nm Anisotropic Pattern Transfer via Colloidal Lithography of a Self-Assembled GdF3 Nanocrystal Monolayer.

Patterning materials with nanoscale features opens many research opportunities ranging from fundamental science to technological applications. However, current nanofabrication methods are ill-suited for sub-5 nm patterning and pattern transfer. We demonstrate the use of colloidal lithography to transfer an anisotropic pattern of discrete features into substrates with a critical dimension below 5 nm. The assembly of monodisperse, anisotropic nanocrystals (NCs) with a rhombic-plate morphology spaced by dendrimer ligands results in a well-ordered monolayer that serves as a 2D anisotropic hard mask pattern. This pattern is transferred into the underlying substrate using dry etching followed by removal of the NC mask. We exemplify this approach by fabricating an array of pillars with a rhombic cross-section and edge-to-edge spacing of 4.4 ± 1.1 nm. The fabrication approach enables broader access to patterning materials at the deep nanoscale by implementing innovative processes into well-established fabrication methods while minimizing process complexity.

A Machine-Learning Approach to Correcting Non-Ideal Background Currents in Disordered Self-Assembled Monolayers

In traditional studies of electroactive molecules tethered to metal surfaces through well-ordered self-assembled monolayers (SAMs), cyclic voltammetry is the primary tool used to measure the coverage of the tethered molecules. The charge under the peak in the voltammogram is directly proportional to the coverage of the redox-active molecules. Accurate coverage measurements are possible because well-ordered SAMs exhibit ideal background currents which are easy to subtract from the total current to isolate the SAMs faradaic current. However, for disordered electroactive SAMs with poor surface blocking properties, specific interactions with the metal substrate create non-ideal background currents which are difficult to separate from the SAMs faradaic current. Although analytical approaches exist to account for background currents in other electrochemical systems, they have some fundamental limitations that impede their practical application to electroactive SAMs. In our work, we propose a simple machine-learning approach to empirically correct for background currents in disordered SAMs, and we apply this approach to determine the surface coverage of partially-desorbed ferrocene-terminated monolayers (Fc-SAMs) from gold surfaces. We use LASSO regression and an ensemble of background scans from partially-desorbed unfunctionalized decanethiol SAMs to approximate the Fc-SAM background currents. Using the approximated background, we estimate the coverage of Fc-SAMs after background correction. This technique allows us to explore Fc-SAM coverage as a function of potential when applying potentials near and beyond the onset of the so-called reductive desorption potential of the SAM which induces non-ideal background currents. To verify the accuracy of the coverages determined using our LASSO method, we used two verification methods: 1) backfilling with decanethiol and 2) chemical stripping of the disordered SAM followed by inductively-coupled plasma-mass spectrometry (ICP-MS). The pros and cons of both confirmation methods will be discussed along with a comparison of error rates and limits of detection between traditional background subtraction method and the LASSO method. We propose that this new approach will enable a more quantitative description of disordered SAM films after reductive desorption events.

ADSORPTION-INDUCED INCREASING SPECULARITY OF CONDUCTION ELECTRONS’ SURFACE SCATTERING

We present a review of our investigations on the increasing specularity of surface scattering of conduction electrons on the W(011), Mo(011), and W(001) surfaces after covering the surfaces with well-ordered (sub)monolayers of adsorbed hydrogen or deuterium. The degree of the specularity of surface scattering was estimated on the base of measurements of magnetoresistance of single-crystalline plates, cooled with liquid He, under ultra-high vacuum conditions, and in a strong magnetic field. The structures of adsorbed hydrogen and deuterium layers were determined from LEED patterns. It is found that the magnetoresistance non-monotonically depends on submonolayer hydrogen coverage and degree of the ordering of adsorbed layers, showing a drastic increase of the specularity (which is higher than for the atomically-clean surfaces!) after the formation of the well-ordered [Formula: see text]-H structures and a pronounced increase of the specularity after the formation of the well-ordered [Formula: see text]-2H structure. Changes in the magnetoresistance induced by the ordering of structures of adsorbed H(D) layers are found to corroborate with the adsorption-induced transformation of Fermi contours of surface electronic states obtained in performed DFT calculations. The increase of the specularity of the scattering caused by the ordering of the surface structures is attributed to the decrease of the probability of electronic transitions between the surface and bulk electronic states induced by surface scattering.

Reflection Absorption Infrared Spectroscopy Characterization of SAM Formation from 8-Mercapto-N-(phenethyl)octanamide Thiols with Phe Ring and Amide Groups.

Multifunctional amide-containing self-assembled monolayers (SAMs) provide prospects for the construction of interfaces with required physicochemical properties and distinctive stability. In this study, we report the synthesis of amide-containing thiols with terminal phenylalanine (Phe) ring functionality (HS(CH2)7CONH(CH2)2C6H5) and the characterization of the formation of SAMs from these thiols on gold by reflection absorption infrared spectroscopy (RAIRS). For reliable assignments of vibrational bands, ring deuterated analogs were synthesized and studied as well. Adsorption time induced changes in Amide-II band frequency and relative intensity of Amide-II/Amide-I bands revealed two-state sigmoidal form dependence with a transition inflection points at 2.2 ± 0.5 and 4.7 ± 0.5 min, respectively. The transition from initial (disordered) to final (hydrogen-bonded, ordered) structure resulted in increased Amide-II frequency from 1548 to 1557 cm−1, which is diagnostic for a strongly hydrogen-bonded amide network in trans conformation. However, the lateral interactions between the alkyl chains were found to be somewhat reduced when compared with well-ordered alkane thiol monolayers.

Well-ordered polystyrene colloidal spheres for light addressable potentiometric sensor

Light addressable potentiometric sensor (LAPS) is a flexible addressable potential sensor with many advantages including simple structure, high sensitivity, low manufacturing cost and light addressability. It can help us to achieve a high performance and low cost of LAPS to combine well-ordered polystyrene (PS) colloidal monolayer with fabricating of LAPS. This paper presents an alcohol-assisted interfacial fabrication method for fabricating low-cost, large-scale and well-ordered PS colloidal monolayer for LAPS in a simple laboratory. The effects of dispersants on PS colloidal self-assembly monolayer are investigated. The mechanism of well-ordered PS colloidal monolayer fabricated with methyl alcohol as the dispersant and the mechanism of disordered PS colloidal monolayer fabricated with ethyl alcohol as the dispersant are described in detail. The PS colloidal monolayer as a template, is used in fabrication of honeycomb meshed array working electrode to optimize performance of LAPS. Moreover, it is proved that the area ratio of the honeycomb meshed array to the silicon substrate is a constant which is independent of the diameter of the PS colloidal sphere. LAPS with honeycomb meshed array has an acceptable sensitivity of 53.47 mV/pH and high linearity of 99.8% in the measurement of pH. The change of photocurrent is also compared deeply for optimization. The results show that LAPS with honeycomb meshed array can reduce signal crosstalk between the detection points and improve addressability of LAPS.