Didem Dede, Evelijn Akerboom, Riccardo Brondolin, Tom Veeken, Thomas Hagger, Raphael Lemerle, Esther Alarcon Llado, Valerio Piazza, W Craig Carter, Albert Polman, Anna Fontcuberta I Morral
{"title":"Selective-Area Deposition of Indium and Its Plasmonic Properties.","authors":"Didem Dede, Evelijn Akerboom, Riccardo Brondolin, Tom Veeken, Thomas Hagger, Raphael Lemerle, Esther Alarcon Llado, Valerio Piazza, W Craig Carter, Albert Polman, Anna Fontcuberta I Morral","doi":"10.1021/acsaom.5c00373","DOIUrl":"10.1021/acsaom.5c00373","url":null,"abstract":"<p><p>We present an effective process sequence for the deposition of indium nanostructures using molecular beam epitaxy (MBE) on a silicon substrate. Using a template structure composed of inverted pyramids and V-grooves, we deposit indium nanostructures with various dimensions. Spatially resolved cathodoluminescence spectroscopy (CL) using an electron-beam energy of 30 keV electrons shows a localized surface plasmon (LSP) resonance in spherical particles with a peak wavelength at 300 nm and a full width at half-maximum of 70 nm for the smallest particles (diameter of 85 nm), showing high optical quality of the grown indium. V-groove template structures create indium nanowires for which CL spectroscopy reveals efficient propagation of surface plasmon polaritons (SPPs), and angle-resolved CL on the periodic inverted pyramids reveals optical lattice resonances arising from the array's periodicity. The high optical quality of these nanostructures enables further applications of plasmonic nanostructures in the ultraviolet (UV) spectral range.</p>","PeriodicalId":29803,"journal":{"name":"ACS Applied Optical Materials","volume":"3 12","pages":"2826-2832"},"PeriodicalIF":3.8,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12751113/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145879217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jesus Hernan Mendoza-Castro, Silvia Schobesberger, Artem S Vorobev, Simone Iadanza, Giovanni Magno, Liam O'Faolain, Bernhard Lendl, Marco Grande
{"title":"Flow Injection-Based Refractive Index Sensing with a Si<sub>3</sub>N<sub>4</sub> Photonic Crystal Nanobeam-Microring Fano Resonator.","authors":"Jesus Hernan Mendoza-Castro, Silvia Schobesberger, Artem S Vorobev, Simone Iadanza, Giovanni Magno, Liam O'Faolain, Bernhard Lendl, Marco Grande","doi":"10.1021/acsaom.5c00500","DOIUrl":"10.1021/acsaom.5c00500","url":null,"abstract":"<p><p>Asymmetric optical resonances shaped by Fano interference can provide enhanced signal contrast and tunable lineshapes in integrated photonics. However, realizing and exploiting these effects in fabricated devices remains challenging, as nanofabrication often reduces asymmetry and slope steepness. In this work, we experimentally demonstrate a hybrid silicon nitride photonic crystal nanobeam-microring resonator (PhCN-MRR) for refractive index (RI) sensing and systematically analyze how Fano-induced line shape asymmetry impacts transduction under realistic flow conditions. Despite exhibiting only moderate asymmetry, the PhCN-MRR shows distinct optical advantages for intensity-based detection, demonstrated using glucose solutions as a model analyte. The sensor was integrated into a custom Si<sub>3</sub>N<sub>4</sub> microfluidic platform and tested under both stopped-flow and dynamic flow-injection conditions over concentrations from 0.5 to 10 mg/mL. Time-resolved spectral scans (0.5-1 Hz) enabled dual transduction channels via wavelength shifts (Δλ) and fixed-wavelength intensity changes (Δ<i>I</i>). Compared with a conventional microring resonator (MRR) featuring symmetric Lorentzian responses, the PhCN-MRR exhibited comparable Δλ sensitivities (∼111 to 113 nm/RIU) but delivered enhanced Δ<i>I</i> responsivity and improved contrast at low concentrations (e.g., 2 mg/mL) due to its asymmetric resonance slopes. These results link controlled Fano asymmetry to measurable sensing gains, demonstrating how modestly asymmetric resonances can improve real-time refractometric detection and expand the design space of Si<sub>3</sub>N<sub>4</sub> photonic platforms for lab-on-chip analytical applications.</p>","PeriodicalId":29803,"journal":{"name":"ACS Applied Optical Materials","volume":"3 12","pages":"2946-2959"},"PeriodicalIF":3.8,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12751107/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145879172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ryan Bower, Daniel A L Loch, Ethan Muir, Bruno Rente, Xiaofei Xiao, Ming Fu, Papken Eh Hovsepian, Arutiun P Ehiasarian, Rupert Oulton, Peter K Petrov
{"title":"TiN Plasmonic Metamaterial Arrays Fabricated at Low Temperatures on Versatile Substrates.","authors":"Ryan Bower, Daniel A L Loch, Ethan Muir, Bruno Rente, Xiaofei Xiao, Ming Fu, Papken Eh Hovsepian, Arutiun P Ehiasarian, Rupert Oulton, Peter K Petrov","doi":"10.1021/acsaom.5c00449","DOIUrl":"10.1021/acsaom.5c00449","url":null,"abstract":"<p><p>Transition metal nitrides (TMNs) have emerged as promising alternative materials for plasmonic and optoelectronic applications in the visible and near-IR spectral ranges. However, the deposition of TMNs with optical properties suitable for plasmonic applications typically requires high temperatures (>800 °C). In this work, we use high-power impulse magnetron sputtering (HIPIMS) to deposit plasmonic TiN thin films at room temperature, without intentional heating. HIPIMS increases the energies of metal ions and dissociated nitrogen (N<sup>1+</sup>) in the flux, enabling the low-temperature deposition of high-quality TiN thin films on a range of industrially relevant substrates, including flexible polymer substrates. We demonstrate that the room-temperature deposition method can be used to produce plasmonic TiN nanoarrays via colloidal lithography, with tunable shapes and dimensions, creating features on the order of 100-500 nm. We characterize the optical response and plasmonic performance of these nanoarrays, demonstrating tailorable resonances in the visible and NIR spectral range, in agreement with optical simulations reported here.</p>","PeriodicalId":29803,"journal":{"name":"ACS Applied Optical Materials","volume":"3 12","pages":"2883-2892"},"PeriodicalIF":3.8,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12751110/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145879284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Taichi Goto, Takumi Koguchi, Yuki Yoshihara, Hibiki Miyashita, Kanta Mori, Toshiaki Watanabe, Allison C Kaczmarek, Pang Boey Lim, Mitsuteru Inoue, Caroline A Ross, Kazushi Ishiyama
{"title":"Magnetotaxial Perpendicular Magnetic Anisotropy and Enhanced Faraday Rotation in Ion Beam Sputtered Cerium-Substituted Yttrium Iron Garnet.","authors":"Taichi Goto, Takumi Koguchi, Yuki Yoshihara, Hibiki Miyashita, Kanta Mori, Toshiaki Watanabe, Allison C Kaczmarek, Pang Boey Lim, Mitsuteru Inoue, Caroline A Ross, Kazushi Ishiyama","doi":"10.1021/acsaom.5c00496","DOIUrl":"10.1021/acsaom.5c00496","url":null,"abstract":"<p><p>Ferrimagnetic iron garnets are valuable for photonic and spintronic devices because of their large magnetooptical (MO) effects and tunable magnetic anisotropy and domain structures. In particular, cerium-substituted yttrium iron garnet (Ce:YIG) has an excellent MO figure of merit in the near-infrared region. However, achieving perpendicular magnetic anisotropy (PMA) in Ce:YIG films has conventionally relied on strain engineering, constraining the relationship between substrate lattice parameters and magnetic properties. We demonstrate strain-independent PMA in epitaxially grown Ce:YIG (Ce<sub>0.9</sub>Y<sub>2.1</sub>Fe<sub>5</sub>O<sub>12</sub>) films on two different (111)-oriented garnet substrates using ion beam sputtering. Despite opposite strain states (tensile and compressive), both films exhibit robust PMA with labyrinth-shaped magnetic domains with widths of 219 nm. Comprehensive surface and interface characterization reveals high-quality epitaxial growth with coherent film-substrate interfaces. The films demonstrated superior MO performance with a Faraday rotation of -1.05°/μm and a figure of merit of 74.7°/dB at 1064 nm wavelength. Detailed anisotropy analysis reveals that magnetotaxial (growth-induced) anisotropy of up to ∼30 kJ/m<sup>3</sup> dominates over magnetoelastic contributions, enabling strain-independent PMA formation. Three-dimensional (3D) micromagnetic simulations confirm mixed Néel-Bloch domain wall configurations. This work demonstrates that PMA in Ce:YIG films can be achieved through magnetotaxial anisotropy independent of the substrate strain state, providing valuable insights for magnetooptical material design.</p>","PeriodicalId":29803,"journal":{"name":"ACS Applied Optical Materials","volume":"3 12","pages":"2923-2934"},"PeriodicalIF":3.8,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12751105/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145879258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sonny Brebels, Emma V Puttock, Tom Cardeynaels, Kamile Bareikaite, Lucy A Weatherill, Melissa Van Landeghem, Huguette Penxten, Andrew Danos, Koen Vandewal, Andrew P Monkman, Benoît Champagne, Wouter Maes
{"title":"A Direct Arylation Approach toward Thermally Activated Delayed Fluorescence-Active Benzo[<i>c</i>][1,2,5]thiadiazole Emitters for Near-Infrared Solution-Processed OLEDs.","authors":"Sonny Brebels, Emma V Puttock, Tom Cardeynaels, Kamile Bareikaite, Lucy A Weatherill, Melissa Van Landeghem, Huguette Penxten, Andrew Danos, Koen Vandewal, Andrew P Monkman, Benoît Champagne, Wouter Maes","doi":"10.1021/acsaom.5c00340","DOIUrl":"10.1021/acsaom.5c00340","url":null,"abstract":"<p><p>An isomeric emitter (<b>2TPA-iCNBT</b>) is designed and synthesized, displaying enhanced thermally activated delayed fluorescence (TADF) properties as compared to the reference near-infrared (NIR) emitter TPACNBz (hereafter referred to as <b>2TPA-CNBT</b>). Its modified benzo-[<i>c</i>]-[1,2,5]-thiadiazole-4,7-dicarbonitrile (<b>iCNBT</b>) acceptor (A) core positions the two triphenylamine (TPA) donor (D) units adjacently, thereby increasing the D-A torsion angle. Synthesis is realized through the use of an unexploited direct arylation strategy, which, besides offering the desired materials in an efficient and straightforward way, can also yield monofunctionalized emitters (<b>1TPA-CNBT</b> and <b>1TPA-iCNBT</b>). In total, four emitters are synthesized, characterized, and subsequently compared in terms of their spectroscopic and device properties. Density functional theory is applied to simulate their relative molecular geometry and the arrangement of their (emissive) excited states. Steady-state and time-resolved emission spectroscopy reveal strongly contrasting TADF properties, with <b>2TPA-iCNBT</b> exhibiting the largest increase in the photoluminescence quantum yield on removal of oxygen (from 27 to 55%), and the fastest TADF emission kinetics in doped films (<i>k</i> <sub>RISC</sub> ∼ 10<sup>5</sup> s<sup>-1</sup>). In solution-processed organic light-emitting diodes, decent maximum external quantum efficiency (EQE) values are obtained for <b>2TPA-iCNBT</b> (2.49%), <b>1TPA-CNBT</b> (2.91%), and <b>1TPA-iCNBT</b> (2.76%), in clear contrast to <b>2TPA-CNBT</b> (1.16%), highlighting the decisive role of the D-A substitution pattern (and the number of D groups) on the performance of NIR-TADF emitters. Furthermore, <b>2TPA-iCNBT</b> is shown to maintain the highest EQE at larger current densities (EQE = 1.98% at 10 mA cm<sup>-2</sup>) within the investigated series, a consequence of its standout TADF behavior.</p>","PeriodicalId":29803,"journal":{"name":"ACS Applied Optical Materials","volume":"3 11","pages":"2583-2594"},"PeriodicalIF":3.8,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12671064/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145670145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marlo Vega, Jean-François Bryche, Julien Moreau, Michael Canva
{"title":"Plasmonic Film with Diluted Nanostructures for Light Energy Harvesting and Sensing.","authors":"Marlo Vega, Jean-François Bryche, Julien Moreau, Michael Canva","doi":"10.1021/acsaom.5c00307","DOIUrl":"10.1021/acsaom.5c00307","url":null,"abstract":"<p><p>Harvesting the electromagnetic light field in spatially dispersed nanostructures and focusing the sensing events at those locations enables a gain of several orders of magnitude in sensitivity. It significantly reduces the amount of target material needed to produce a measurable signal. This paper establishes that, contrary to common belief, at very low target concentrations, increasing the periodicity of a nanoparticle array instead of diminishing it significantly lowers the limit of detection (LOD) of such structured plasmonic sensors. We demonstrate this numerically on a thin gold film covered by an array of 50 nm diameter nanocylinders with periodicity ranging from 400 to 3000 nm. We found a minimal capture target volume per surface unit of a few tens of nm<sup>3</sup>/μm<sup>2</sup>, which is an improvement of orders of magnitude from about 10<sup>4</sup> nm<sup>3</sup>/μm<sup>2</sup> necessary for obtaining the same minimal signal using a conventional propagative-based plasmon sensor, or about 10<sup>3</sup> nm<sup>3</sup>/μm<sup>2</sup> for a similar plasmonic biochip structure but with a typical 200-400 nm periodicity array range. Two key mechanisms are involved in achieving such a significant breakthrough. First, energy harvesting is enhanced by incorporating the underlying thin film, which enables the coupling of electromagnetic field energy into the localized plasmon mode of the nanoparticles. This harvesting coupling effect is shown to be limited by the film's plasmon propagation attenuation length and, consequently, its appropriate thickness. Second, target binding events must be precisely positioned in areas of enhanced optical field intensity.</p>","PeriodicalId":29803,"journal":{"name":"ACS Applied Optical Materials","volume":"3 10","pages":"2329-2338"},"PeriodicalIF":3.8,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12560813/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145402169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kristine Q Loh, Nathan J Eylands, Vivian E Ferry, Uwe R Kortshagen
{"title":"Spectral Engineering with Quantum Dot Films for Enhanced Crop Growth.","authors":"Kristine Q Loh, Nathan J Eylands, Vivian E Ferry, Uwe R Kortshagen","doi":"10.1021/acsaom.5c00338","DOIUrl":"10.1021/acsaom.5c00338","url":null,"abstract":"<p><p>Passive spectral manipulation strategies tune transmitted sunlight to more optimal wavelengths for plant growth. Quantum dots (QDs) embedded in polymer films are a promising material system for this application. Here, we simulate lettuce growth under nine different nontoxic QD films. QDs that strongly absorb blue/green light and downshift it to red/far-red wavelengths result in yield enhancements of up to 45%. We find that these QD films can be utilized broadly in greenhouses in the United States. Contrary to prevailing belief, increasing the intensity of down-shifted photoluminescence does not further increase yield, indicating that QD absorption is the most important factor.</p>","PeriodicalId":29803,"journal":{"name":"ACS Applied Optical Materials","volume":"3 10","pages":"2251-2256"},"PeriodicalIF":3.8,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12560175/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145402149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jasper van Gastel, Pyry Kivisaari, Jani Oksanen, Elias Vlieg, John J Schermer
{"title":"Design of PV Cells and LEDs Robust to Grid Shadowing Losses in Emission.","authors":"Jasper van Gastel, Pyry Kivisaari, Jani Oksanen, Elias Vlieg, John J Schermer","doi":"10.1021/acsaom.5c00269","DOIUrl":"10.1021/acsaom.5c00269","url":null,"abstract":"<p><p>In photovoltaics, it is generally assumed that the emission and absorption efficiency is linearly affected by the grid coverage fraction. Typically, the top grid is therefore optimized to allow maximal light exposure with minimal electrical resistance, while the optical properties of the grid are not treated to the same extent. In this work, we provide a numerical study that shows that as a result of the optical properties of the grid, the light extraction efficiency and resulting emission changes nonlinearly with grid coverage, contrary to the standard approximation. If the grid is optically lossy while light is mostly trapped in the diode, the loss in emission is more than linear and therefore larger than expected based on the standard grid shadowing assumption. However, with an optically reflective grid and a good light extraction scheme, the structure obtains a robustness against losses from grid, leading to a meaningful increase in the light extraction efficiency. This is shown using a simple 300 nm GaAs light-emitting diode (LED) structure the emissive properties of which generalize to a thin-film PV cell. Specifically, it is found that depending on the design of the grid and backside mirror, at 10% grid coverage the light extraction efficiency need only be reduced less than 4% absolute. Conversely, in particularly detrimental cases, at 10% grid coverage the light extraction efficiency is reduced by over 35% absolute.</p>","PeriodicalId":29803,"journal":{"name":"ACS Applied Optical Materials","volume":"3 9","pages":"2153-2162"},"PeriodicalIF":3.8,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12481568/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145207802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniela F. Duarte, Gilberto J. Arruda, Luiz A. O. Nunes, Sandro M. Lima and Luis H. C. Andrade*,
{"title":"Green Synthesis of Tb3+-Doped CaMoO4 Nanothermometers Using Plant Extract: Enhanced Optical Properties for Temperature Sensing Applications","authors":"Daniela F. Duarte, Gilberto J. Arruda, Luiz A. O. Nunes, Sandro M. Lima and Luis H. C. Andrade*, ","doi":"10.1021/acsaom.5c00208","DOIUrl":"https://doi.org/10.1021/acsaom.5c00208","url":null,"abstract":"<p >Luminescent temperature sensors enable precise thermal monitoring at cellular levels, facilitating cancer treatment approaches and industrial process monitoring across wide temperature ranges. These sensors, when constructed from inorganic matrices incorporating specific luminescence-activating centers, allow temperature estimation through their emission characteristics. This work investigates the optical properties of Tb<sup>3+</sup>-doped CaMoO<sub>4</sub> crystals synthesized via an environmentally friendly coprecipitation method using an extract from the leaves of the <i>Tabebuia aurea</i> tree. Spectroscopic characterization confirms the formation of the CaMoO<sub>4</sub> crystalline phase and successful incorporation of Tb<sup>3+</sup> ions into the crystal lattice. Particle morphology was examined using scanning electron microscopy. Temperature-dependent luminescence measurements reveal exceptional performance as an optical sensor, with a calculated relative sensitivity of 2.8% K<sup>–1</sup> at 363 K, surpassing previously reported values for other Tb<sup>3+</sup>-doped materials. This green synthesis approach demonstrates that environmentally sustainable methods can produce nanothermometers with enhanced sensing capabilities, surpassing conventionally synthesized alternatives, and with significantly reduced organic residues, which correlates with a superior radiative lifetime and excellent stability and reproducibility for practical applications.</p>","PeriodicalId":29803,"journal":{"name":"ACS Applied Optical Materials","volume":"3 8","pages":"1810–1820"},"PeriodicalIF":3.8,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/acsaom.5c00208","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144885187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Heterovalent Substitution of K2SrP2O7:Cr3+ to Achieve Anti-Thermal-Quenching Broadband Near-Infrared Luminescence","authors":"Hexi Zhang, and , Yuanbing Mao*, ","doi":"10.1021/acsaom.5c00201","DOIUrl":"https://doi.org/10.1021/acsaom.5c00201","url":null,"abstract":"<p >Broadband near-infrared (NIR) light sources based on phosphor-converted light-emitting diodes are highly desirable for biochemical analysis and medical diagnosis applications. However, thermal quenching remains a demanding challenge for developing efficient NIR phosphors. Herein, we report the enhancement of both quantum efficiency and thermal stability in Cr<sup>3+</sup>-activated K<sub>2</sub>SrP<sub>2</sub>O<sub>7</sub> phosphors through a heterovalent substitution strategy by replacing Sr<sup>2+</sup> with Al<sup>3+</sup> in K<sub>2</sub>Sr<sub>1–<i>x</i></sub>Al<sub><i>x</i></sub>P<sub>2</sub>O<sub>7</sub> (0.05 ≤ <i>x</i> ≤ 0.2) to obtain optimized broadband NIR emission. Structural modulation via Al<sup>3+</sup> substitution leads to the optimized composition, K<sub>2</sub>Sr<sub>0.88</sub>Al<sub>0.1</sub>P<sub>2</sub>O<sub>7</sub>:0.02Cr<sup>3+</sup>, which emits across a broad NIR range of 650–1100 nm peaking at 807 nm with a full width at half-maximum of ∼130 nm under 448 nm excitation. Remarkably, its emission intensity at 150 °C remains 120% of the initial value at room temperature, demonstrating a rare antithermal-quenching behavior. Temperature-dependent XRD studies further reveal that Al<sup>3+</sup> substitution effectively suppresses lattice expansion at elevated temperatures, indicating enhanced lattice stability under thermal excitation. Detailed structural and spectral analyses show that the substitution enhances local site symmetry, reduces electron–phonon coupling, increases thermally induced absorption probability, and fortifies energetic barriers against nonradiative transitions. These synergistic effects collectively endow this NIR phosphor with a superior thermal stability. Furthermore, NIR light-emitting diodes fabricated with this phosphor exhibit strong potential for applications in information identification, nondestructive detection, and night vision technologies. This study demonstrates a local structure engineering strategy for designing thermally robust Cr<sup>3+</sup>-activated NIR phosphors, offering valuable insights into material discovery and NIR spectroscopy device development.</p>","PeriodicalId":29803,"journal":{"name":"ACS Applied Optical Materials","volume":"3 8","pages":"1766–1776"},"PeriodicalIF":3.8,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/acsaom.5c00201","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144885252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}