Optical Absorption Properties Research Articles

Recent progress in atomically precise metal nanoclusters for photocatalytic application.

Photocatalysis is a widely recognized green and sustainable technology that can harness inexhaustible solar energy to carry out chemical reactions, offering the opportunity to mitigate environmental issues and the energy crisis. Photocatalysts with wide spectral response and rapid charge transfer capability are crucial for highly efficient photocatalytic activity. Atomically precise metal nanoclusters (NCs), an emerging atomic-level material, have attracted great interests owing to their ultrasmall size, unique atomic stacking, abundant surface active sites, and quantum confinement effect. In particular, the molecule-like discrete electronic energy level endows them with small-band-gap semiconductor behavior, which allows for photoexcitation in order to generate electrons and holes to participate in the photoredox reaction. In addition, metal NCs exhibit strong light-harvesting ability in the wide spectral UV-near IR region, and the diversity of optical absorption properties can be precisely regulated by the composition and structure. These merits make metal NCs ideal candidates for photocatalysis. In this review, the recent advances in atomically-precise metal NCs for photocatalytic application are summarized, including photocatalytic water splitting, CO2 reduction, organic transformation, photoelectrocatalytic reactions, N2 fixation and H2O2 production. In addition, the strategy for promoting photostability, charge transfer and separation efficiency of metal NCs is highlighted. Finally, a perspective on the challenges and opportunities for NCs-based photocatalysts is provided.

The coexistence of high piezoelectricity and superior optical absorption in Janus Bi2X2Y (X = Te, Se; Y = Te, Se, S) monolayers.

Bismuth chalcogenide and its derivatives have been attracting attention in various fields as semiconductors or topological insulators. Inspired by the high piezoelectric properties of Janus Bi2TeSeS monolayer and the excellent optical absorption properties of the Bi2X3 (X = Te, Se, S) monolayers, we theoretically predicted four new-type two-dimensional (2D) monolayers Janus Bi2X2Y (X = Te, Se; Y = Te, Se, S) using the first principles combined with density functional theory (DFT). The thermal, dynamic, and mechanical stabilities of Janus Bi2X2Y monolayers were confirmed based on ab initio molecular dynamics (AIMD) simulations, phonon dispersion, and elastic constants calculations. Their elastic properties, band structures, piezoelectric, and optical properties were systematically investigated. It was found that Janus Bi2X2Y monolayers have a typical Mexican hat-shaped valence band edge structure and, therefore, have a ring-shaped flat band edge, which results in their indirect band gaps. The results show that Janus Bi2X2Y monolayers are semiconductors with moderate band gaps (0.62-0.98 eV at the HSE + SOC level). After considering the electron-phonon renormalization (EPR), the band gaps are reduced by less than 5% at 0 K under the zero-point renormalization (ZPR) and further reduced by approximately 10% at 300 K. Besides, Janus Bi2X2Y monolayers also exhibit excellent optical absorption properties in the blue-UV light region, with the peak values at the order of 8 × 105 cm-1. Particularly, the Janus Bi2Te2S monolayer was found to exhibit a piezoelectric strain coefficient d11 of up to 20.30 pm V-1, which is higher than that of most of the 2D materials. Our results indicate that Janus Bi2X2Y monolayers could be promising candidates in solar cells, optical absorption, and optoelectronic devices; especially, a Janus Bi2Te2S monolayer can also be an excellent piezoelectric material with great prospects in the fields of mechanical and electrical energy conversion.

Photophysics of a nucleic acid-protein crosslinking model strongly depends on solvation dynamics: an experimental and theoretical study.

We present a combined experimental and theoretical study of the photophysics of 5-benzyluracil (5BU) in methanol, which is a model system for interactions between nucleic acids and proteins. A molecular dynamics study of 5BU in solution through efficient DFT-based hybrid ab initio potentials revealed a remarkable conformational flexibility - allowing the population of two main conformers - as well as specific solute-solvent interactions, which both appear as relevant factors for the observed 5BU optical absorption properties. The simulated absorption spectrum, calculated on such an ensemble, enabled a molecular interpretation of the experimental UV-Vis lowest energy band, which is also involved in the induced photo-reactivity upon irradiation. In particular, the first two excited states (mainly involving the uracil moiety) both contribute to the 5BU lowest energy absorption. Moreover, as a key finding, the nature and brightness of such electronic transitions are strongly influenced by 5BU conformation and the microsolvation of its heteroatoms.

Improving the optical properties of CuCoMnOx spinel absorber using ZnO nanorod arrays for thermal collector and photocatalytic applications

Solar-selective and high entropy materials are one of the key factors for thermal applications. CuCoMnOx (CCMO) spinel compound is also a suitable material for this purpose due to its spin-allowed transitions in partially filled d orbitals. In this study, the CCMO absorber compound was coated on ZnO nanorod-coated aluminum (Al) substrates for the first time by the sol-gel dip-coating method, and its optical, structural, and morphological properties were examined. According to the results obtained, ZnO nanorods increased the active surface area of the Al substrate and accordingly increased the absorptance value of the CCMO material from 87 % to 94 %. Analyzes performed with FT-IR spectrometry showed that the thermal emittance values were 90 % and 67 % for Al/CCMO and Al/ZnO/CCMO samples, respectively. The thermal emittance reduced by around 25 % with the use of ZnO nanorods on the Al substrates in the wavelength range of 2.5 μm–25 μm. The photocatalytic effect of this spinel compound was also investigated. The degradation spectra of organic methylene blue (MB) solution within 120 min were examined with UV–Vis spectroscopy, and the degradation efficiency increased by 23 % in the presence of ZnO nanorods. The obtained results showed that ZnO nanorod structures significantly changed both the solar and photocatalytic properties of the CCMO compound.

Transition metal (Mn, Fe, Co, Ni) and nitrogen co-doping for improving the photocatalytic activity of monolayer MoS2

Exploring efficient photocatalyst is important for environmental protection. In this work, we systematically investigate the doping configuration, formation energy, band structures, density of state, recombination rate, catalytic active site, work function, redox potential, and optical absorption properties of transition metal and nitrogen co-doped monolayer MoS2. In transition doped MoS2, transition metal atoms replace Mo. Transition metal and nitrogen atoms substitute Mo and S atoms in transition metal and nitrogen co-doped MoS2, respectively. Compared with undoped MoS2, transition metal and nitrogen co-doped MoS2 have low photogenerated carrier recombination rate, abundant catalytic active sites, small work function, suitable redox potentials, and strong light absorption, especially Mn-N and Ni-N co-doped MoS2.

Structural Instability Stimulated Heteroatoms Co‐Doping of 2D Quaternary Semiconductor for Optoelectronic Applications

AbstractAlthough the structural and electrical engineering of transition metal dichalcogenides using atomic doping or doping‐induced phase modulation can be used to attain high‐performance and wavelength‐tunable optoelectronic devices, accessible substitutional doping to overcome the large lattice mismatch between the host and guest atom‐related bonding states remains elusive. This study corroborates an innovative synthetic route for molybdenum disulfide (MoS2)‐derived two‐dimensional (2D) quaternary semiconductors substitutionally doped with Re and O using a solution‐based large‐area compatible approach combined with the thermal evaporation of dopants. The substitutional doping of Re into MoS2 crystals with a large lattice mismatch is effectively accomplished by adopting structurally unstable host films, resulting in the large‐scale synthesis of 2D quaternary multi‐layers with a Re doping concentration >10%. Comprehensive spectroscopic and microscopic evaluations are performed to determine the efficacy of the host films with structural instability for the synthesis of 2D RexMo(1‐x)O2yS2(1‐y) quaternary multi‐layers. The capability of the quaternary semiconductor for versatile nanophotonic devices is validated by ascertaining the simultaneous enhancement of the photoelectrical properties with wide‐range optical absorption and photoelectrochemical properties, as compared with those of their binary counterparts.

Preparation and photocatalytic performance of nanosheet BiOClxBryI1-x-y with high visible light activity by one-pot solvothermal method

A ternary solid solution (BiOClxBryI1-x-y) was constructed in this work to improve the photocatalytic activity of BiOX (X = Cl, Br, I). Compared with BiOCl and BiOBr, the optical absorption properties of BiOClxBryI1-x-y in the visible light region have been enhanced due to their narrower band gap. This enhancement could be attributed to the modulation of electronic structure originated from the coupling of Cl, Br and I. Additionally, the separation of photogenerated carriers has been enhanced, and the active species, h+ and •O2–, contributed more to the photocatalytic performance due to the positions of VB and CB. The pseudo-first-order rate constant of the optimal sample BiOCl0.6Br0.2I0.2 was 14 times higher than that of BiOCl in photodegradation of RhB and 4 times higher in the case of tetracycline.

Revealing the Untapped Potential of Photocatalytic Overall Water Splitting in Metal Organic Frameworks

AbstractThe past decade witnessed substantial attention toward metal‐organic frameworks (MOFs) for photocatalytic water splitting owing to their versatile structural and optoelectronic characteristics. However, MOFs capable of efficient photocatalytic overall water splitting (OWS) remain notably scarce. Although MOF‐based photocatalysts with OWS potential are highly promising due to their diverse building blocks and topological configurations, the vast number of possible MOFs renders traditional trial‐and‐error materials discovery approaches impractical. Herein, a data‐driven methodology that integrates machine learning with high‐throughput first‐principles computations to identify MOFs with OWS capability is presented. By systematically assessing factors including water stability, band gap, band positions, charge carrier transport, and optical absorption properties, 14 MOFs from the Quantum‐MOF (QMOF) database containing over 20,000 MOFs as promising candidates for visible‐light‐driven OWS are identified. Notably, five of them exhibit exceptional electronic and optical properties, outperforming previously reported MOF OWS photocatalysts, such as UIO66(Zr)‐NH2, MIL125(Ti)‐NH2, and MIL53(Al)‐NH2 is established. This work represents a large‐scale, data‐driven exploration of MOF‐based photocatalysts for water splitting, shedding light on the untapped potential of photocatalysis in MOFs.

SCAPS-FDTD simulation of 20.1 % efficient Perovskite-SnS tandem solar cell based on alternative charge transport layers and Au-nanoparticles

Perovskite-based tandem solar cells emerged as potential candidates for efficient photovoltaic applications. These devices exhibit high optical absorption properties and tunable direct band-gap. In this work, a novel lead-free Perovskite-SnS Tandem solar cell based on alternative charge transport layers combined with plasmonic-based light management approach is proposed. Accurate numerical investigation is carried out to assess the influence of the charge transport layers of top sub-cell on the optoelectronic properties of the tandem cell. The obtained results reveal the potential of SnO2 and CuO materials as electron and hole transport layers, respectively, demonstrating a good conduction band offset (CBO) and thereby enhanced recombination losses. Furthermore, the role of Gold-nanoparticles in enhancing absorption and light-trapping mechanisms in the bottom SnS-based sub-cell is investigated using FDTD computations. It is found that the optimized tandem cell with Au-NPs exhibits a high power conversion efficiency of 20.1%. Therefore, this work can open up new paths to boost the power conversion of Sn-based Perovskite/SnS Tandem cells for high-performance and eco-friendly photovoltaic applications.

Advancing understanding of structural, electronic, and magnetic properties in 3d-transition-metal TM-doped α-Ga2O3 (TM = V, Cr, Mn, and Fe): A first-principles and Monte Carlo study

In this paper, we investigated the properties of transition metal (TM)-doped α-Ga2O3 using first-principles calculations and Monte Carlo simulations. α-Ga2O3 is a wide-bandgap semiconductor material with enhanced performance and lower fabrication costs on sapphire substrates compared to β-Ga2O3. Doping with TMs can modify electrical transport, optical absorption, and magnetic properties, yet theoretical studies on this are scarce. Our study focused on V, Cr, Mn, and Fe impurities. We introduced a newly proposed scheme for efficiently determining the ground-state defect configuration during structural relaxation. We adopt a recent, novel image charge correction method to accurately calculate formation enthalpy and thermodynamic transition levels for spin-polarized transition metal ion doping, without employing the empirical dielectric constant. Results showed Cr ions tend to neutral substitutional Ga, while V, Mn, and Fe impurity ions tend to carry a negative charge in common n-type α-Ga2O3. Magnetic moments and spin-splitting impurity levels primarily arise from transition metal impurities and their d orbitals. We used the generalized four-state method to calculate exchange interaction constants between substitution lattice sites and identified (anti) ferromagnetic couplings at specific distances in a 120-atom supercell, which are negligible in total energy calculations. Monte Carlo simulations indicated a Curie temperature of 360 K in n-type α-Ga2O3: Mn system with 12.5% doping, suggesting intrinsic ferromagnetic ordering based on the Heisenberg model. Our study contributes to understanding TM-doped α-Ga2O3 electronic structure and magnetic properties through improved methodologies. The approach can be applied in research involving other TM-doped oxides or wide-bandgap semiconductors.

Study of blue-light emission properties of WO3:Eu microstructures

Structural, surface morphological, optical absorption and emission properties of 0–5% Eu doped WO3 samples are studied. The samples are synthesised by acidic precipitation method. The structural analysis reveals that the sample has ‘room-temperature monoclinic’ structure. The average crystallite size of the undoped sample is ∼58.57 nm and it decreases to 34.72 nm after doping of Eu at 5%. The undoped sample has hexagonal disc-like grain structures with average diameter of ∼0.84 μm. All the samples show a sharp absorption edge above 350 nm. The transmittance of the samples increases above 400 nm and reaches its maximum at ∼490 nm. The extinction coefficient of the undoped sample is minimum at 390 nm and it has a relatively smaller value than that of the doped samples. The optical bandgap of the undoped sample is found to be 3.56 eV and it decreases to 3.28 eV with the increase of concentration of Eu to 5%. Analyses of PL spectra show that the undoped sample under 355 nm UV excitation produces a broad blue emission band with five maxima at ∼403, 414, 435, 473 and 495 nm due to band-to-band transitions and transitions involving intrinsic defects. A blue emission band centred at ∼435 nm is increased by two-fold after doping of Eu at 1%. In addition, a secondary emission band is found at ∼505 nm due to formation of an aggregate defect (F2 centre). When the doping concentration is increased to 5%, another secondary band is observed at 610 nm due to interstitial Eu3+ centre. The enhancement of the blue emission band is attributed to formation of oxygen vacancies due to substitution of W6+ ions by Eu3+ ions. The enhanced blue light in the sample doped with 1% of Eu has potential application in WLED as well as other light emitting applications.

Synthesis of Graphene Quantum Dots: A Comprehensive Review

Semiconductor quantum dots such as CdSe, PbSe, PbS, CdS, CuInS, CuInSe, etc. have been extensively studied for their size-tunable optical absorption and emission properties, which enable their applications in different optoelectronics applications. Although despite having high photoaborption and photosensing properties these semiconductor quantum dots possess certain limitation due to their high level of toxicity and complex synthesis process. Graphene quantum dots (GQDs) are a zero-dimensional (0D) nontoxic nanomaterial of the carbon family, and have sparked a lot of attention in the domains of optoelectronics and electronics. In this review, a number of GQD synthesis methods such as laser ablation, hydrothermal, solvothermal, thermal pyrolysis, electrochemical, chemical oxidation and cutting have been summarized in detail.

Investigation on Optical Absorption and Reflection of Carbon Nanotubes Mixed Copper Composites for Laser Sintering Process Improvement

Selective laser sintering (SLS) of copper components manufactured via powder metallurgy is widely studied due to minimal material wastage. However, copper has poor optical absorption when exposed to infrared (IR) lasers, such as in laser-based additive manufacturing or laser surface processing. To address this issue, an innovative approach to enhance the optical absorption of copper powders during infrared laser sintering is presented in this study. Carbon nanotubes (CNTs) have several unique properties, including their high surface area, plasmonic response, excellent conductivity, and optical absorption properties. CNTs were mixed with copper powders at different weight percentages using an acoustic method. The resulting Cu-CNT compositions were fabricated into pellets. The Box-Behnken Design of Experiments methodology was used to optimize the IR laser processing conditions for sintering. Spectroscopic analysis was conducted to evaluate the reflection and thermal absorption of the IR wavelengths by the Cu-CNT composites. Density and hardness measurements were taken for the laser-sintered Cu-CNT pellets. The coating of copper powders with CNTs demonstrated enhanced optical absorption and correspondingly reduced reflection. Due to the enhanced optical absorption, increased control and sensitivity of the laser sintering process was achieved, which enabled improvement in the mechanical properties of strength, hardness, and density, while also enabling control over the composite thermal expansion coefficient. A maximum average hardness of 66.5 HV was observed. Indentation test results of the samples revealed maximum tangential and radial stresses of 0.148 MPa and 0.058 Mpa, respectively.

VTe2: Broadband Saturable Absorber for Passively Q-Switched Lasers in the Near- and Mid-Infrared Regions.

In this study, we demonstrate the fabrication of a novel 2D transition metal dichalcogenide, VTe2, into a saturable absorber (SA) by using the liquid phase exfoliation method. Furthermore, the first-principles calculations were conducted to elucidate the electronic band structures and absorption spectrum. The nonlinear optical absorption properties of VTe2 at 1.0, 2.0, and 3.0 μm were measured using open-aperture Z-scan and P-scan methods, which showed saturation intensities and modulation depths of 95.57 GW/cm2 and 9.24%, 3.11 GW/cm2 and 7.26%, and 15.8 MW/cm2 and 17.1%, respectively. Furthermore, in the realm of practical implementation, the achievement of stable passively Q-switched (PQS) lasers employing SA composed of few-layered VTe2 nanosheets has manifested itself with broadband operating wavelengths from 1.0 to ∼3.0 μm. Specifically, PQS laser operations from near-infrared to mid-infrared with pulse durations of 195 and 563 ns for 1.0 and 2.0 μm solid-state lasers, respectively, and 749 ns for an Er3+-doped fluoride fiber laser at 3.0 μm were obtained. Our experimental results demonstrate that VTe2 is a potential broadband SA device for achieving PQS lasers. To the best of our knowledge, this is the first demonstration of using VTe2 as an SA in PQS lasers in the near- and mid-infrared regions, which highlights the potential of VTe2 for future research and applications in optoelectronic devices.

Fabrication of g-C3N4/CuS heterostructures for efficient visible light-driven photocatalysts

The g-C3N4/CuS heterojunction was synthesized using a wet impregnation process. Powder X-ray diffraction (PXRD), High resolution scanning electron microscopy (HR-SEM), X-ray photoelectron spectroscopy (XPS), Diffused reflectance spectroscopy (UV–vis DRS), and Photoluminescence (PL) were employed to examine the crystalline structure, morphology, elemental configuration, optical absorption characteristics, electron hole recombination, and charge transfer property of the prepared materials, respectively. The specific surface area and pore volume of the produced materials were calculated using N2 adsorption–desorption isotherms and BET studies. Rhodamine B (RhB) is broken down by the catalysts in the presence of visible light. In 40 min, the catalyst showed quick photocatalytic degradation of the RhB dye (98.6 %). The synthesized catalyst performs at the highest level for photocatalytic degradation due to its low e-h recombination rate, broad spectrum of absorption light, increased photo-generated electrons, and larger specific surface area. Higher photocatalytic activity might be a result of the matched overlapping band structure and the interaction between CuS and g-C3N4. The photoluminescent spectra show that the interaction of g-C3N4 and CuS would not only boost the optical absorption property of g-C3N4, but would also produce more interfaces for the efficient transfer of photo-generated electron-hole pairs to limit recombination. The repeatability experiment's results unequivocally demonstrate that the developed catalyst has a high photo-stability. The results of the degrading efficiency tests were competitive with numerous photocatalysts that had already been published.

Nonlinear optical properties and ultrafast carrier dynamics of ultrathin ReSe2.

Rhenium diselenide (ReSe2) has shown great application potential in the field of optical devices because of its excellent optoelectronic properties. In this study, we systematically investigated the nonlinear optical absorption properties of mono- and bi-layer ReSe2 and the ultrafast carrier dynamics process in the ultraviolet to near-infrared spectral range as the essential foundational groundwork for harnessing the potential of ultrathin ReSe2-based optoelectronic devices. We found that ReSe2 has excellent nonlinear absorption performance and a low saturation absorption intensity that is better than that of many semiconductor materials. Meanwhile, pump-probe and transient absorption technology revealed the underlying dynamic mechanisms, including bandgap renormalization and Auger recombination. This study can broaden the horizons of material science and propel the development of different applications of ReSe2.

Tuning the Inter-Nanoplatelet Distance and Coupling Strength by Thermally Induced Ligand Decomposition.

CdSe nanoplatelets (NPLs) are promising 2D semiconductors for optoelectronic applications, in which efficient charge transport properties are desirable. It is reported that thermal annealing constitutes an effective strategy to control the optical absorption and electrical properties of CdSe NPLs by tuning the inter-NPL distance. Combining optical absorption, transmission electron microscopy, and thermogravimetric analysis, it is revealed that the thermal decomposition of ligands (e.g., cadmium myristate) governs the inter-NPL distance and thus the inter-NPL electronic coupling strength. Employing ultrafast terahertz spectroscopy, it is shown that this enhanced electronic coupling increases both the free carrier generation efficiency and the short-range mobility in NPL solids. The results show a straightforward method of controlling the interfacial electronic coupling strength for developing functional optoelectronic devices through thermal treatments.

Photocatalytic and antimicrobial activity of decahedron-like MIL-125(Ti) anchored on AgI towards efficient degradation of tetracycline:activity evaluation, mechanism and pathway

In this work, AgI nanoparticles were anchored on decahedron-like MIL-125(Ti) through wet precipitation method, and the photocatalytic activities were analyzed by tetracycline (TC) degradation rates under simulated sunlight. The structures, morphologies, valence bonds, optical absorption properties, charge separation efficiencies of the prepared samples were tested by XRD, SEM, EDS, XPS, UV–Vis DRS and PL spectroscopy. Compared with pure MIL-125(Ti), AgI@MIL-125(Ti) displayed excellent photocatalytic performance on TC degradation. When the mass fraction of AgI in AgI@MIL-125(Ti) was 10 %, AgI@MIL-125(Ti)-10 % displayed the best photocatalytic efficiency, which 96.9 % of TC was removed under simulated sunlight for 30 min. The results of active species trapping experiments and ESR tests showed that the Z-Scheme heterojunction between AgI and MIL-125(Ti) promoted the separation of photogenerated charges. Furthermore, a part of Ag+ were reduced to Ag NPs in the process of photocatalytic reaction, which constructed a cross-linking bridge for the charges at the interface of AgI and MIL-125(Ti) and further accelerated the electron transmission. The intermediate toxicity experiments proved that the toxic structures are destroyed in TC solution after MIL-125(Ti)-10 % photocatalytic degradation, and the toxicity of the reaction system was reduced effectively.

Direct Z-scheme MoSTe/g-GeC heterostructure for photocatalytic water splitting: A first-principles study

In this paper, based on the first-principle calculations of hybrid density functional theory, the MoSTe/g-GeC of the Z-scheme heterostructure is constructed. The stability, electronic properties, optical absorption properties, and photocatalytic mechanism of the heterostructure is investigated. The band structure of MoSTe/g-GeC heterostructure is staggered, and the bandgap is 0.47 eV. The built-in electric field from g-GeC to MoSTe, with a size of 1.03 eV. The optical absorption coefficient of MoSTe/g-GeC heterostructures is significantly higher than that of MoSTe and g-GeC layer. When pH ranges from 0 to 7, the reduction reaction occurs in g-GeC layer, and the oxidation reaction occurs in the MoSTe layer. In the MoSTe/g-GeC heterostructure under different stresses, the band structure is arranged in a staggered manner. Importantly, under tensile strain, the bandgap of MoSTe/g-GeC heterostructure can be changed from the indirect into a direct bandgap. The bandgap of heterostructure decreases under the strain. In addition, the analysis of the photocatalytic mechanism shows that the redox reaction of the MoSTe/g-GeC heterostructure occurs on the layer with strong redox ability, and their light absorption ability is significantly enhanced compared to single-layers, which effectively improves the photocatalytic properties. It's a potential high-efficiency photocatalytic materials for direct Z-scheme heterostructure.

Heavy water coupling gel for short-wave infrared photoacoustic imaging.

Changes in lipid, water, and collagen (LWC) content in tissue are associated with numerous medical abnormalities (cancer, atherosclerosis, and Alzheimer's disease). Standard imaging modalities are limited in resolution, specificity, and/or penetration for quantifying these changes. Short-wave infrared (SWIR) photoacoustic imaging (PAI) has the potential to overcome these challenges by exploiting the unique optical absorption properties of . This study's aim is to harness SWIR PAI for mapping LWC changes in tissue. The focus lies in devising a reflection-mode PAI technique that surmounts current limitations related to SWIR light delivery. To enhance light delivery for reflection-mode SWIR PAI, we designed a deuterium oxide (, "heavy water") gelatin (HWG) interface for opto-acoustic coupling, intended to significantly improve light transmission above 1200nm. HWG permits light delivery up to 1850nm, which was not possible with water-based coupling ( light delivery up to 1350nm). PAI using the HWG interface and the Visualsonics Vevo LAZR-X reveals a signal increase up to 24dB at 1720nm in lipid-rich regions. By overcoming barriers related to light penetration, the HWG coupling interface enables accurate quantification/monitoring of biomarkers like LWC using reflection-mode PAI. This technological stride offers potential for tracking changes in chronic diseases (in vivo) and evaluating their responses to therapeutic interventions.