Search

This review comprehensively addresses the developments and applications of polymer materials in optoelectronics. Especially, this review introduces how the materials absorb, emit, and transfer charges, including the exciton–vibrational coupling, nonradiative and radiative processes, Förster Resonance Energy Transfer (FRET), and energy dynamics. Furthermore, it outlines charge trapping and recombination in the materials and draws the corresponding practical implications. The following section focuses on the practical application of organic materials in optoelectronics devices and highlights the detailed structure, operational principle, and performance metrics of organic photovoltaic cells (OPVs), organic light-emitting diodes (OLEDs), organic photodetectors, and organic transistors in detail. Finally, this study underscores the transformative impact of organic materials on the evolution of optoelectronics, providing a comprehensive understanding of their properties, mechanisms, and diverse applications that contribute to advancing innovative technologies in the field. [ABSTRACT FROM AUTHOR]

Midinfrared photonic devices are used as lasers and photodetectors in optical gas sensors and fiber‐optic communications. Herein, the pair number dependence and strain compensation dependence of the InAsSb/InAsP superlattice structure to increase luminescence intensity and reduce crystal defects is investigated. InAs substrates are used to demonstrate various effects of strain compensation, including its role in increasing luminescence intensity and improving the surface flatness. Furthermore, the photoluminescence spectra of a grown superlattice between the InAs substrate and GaAs substrate with two‐temperature‐step growth are shown. [ABSTRACT FROM AUTHOR]

In this paper, two-and-three channel all-optical AND logic gates based on four-wave mixing in a highly nonlinear fiber for 120 Gbps on–off keying signals were designed, simulated, and investigated. Simulation results show low bit error rate and consequently fairly high Q-factor at the receiving end in both two and three inputs AND gates, as well as the logic operation, is confirmed by the open eye diagrams with moderate power penalties for both designs. [ABSTRACT FROM AUTHOR]

The synergistic supremacy of a hybrid nanocomposite made of reduced graphene oxide (rGO), molybdenum disulfide (MoS2) and gold nanoparticles (Au) for Q-switching and optical limiting applications is investigated. Hydrothermally synthesized Au-rGO-MoS2 hybrid with varying concentrations of Au (2.5, 5, 7.5 and 10 wt%) was subjected to interact with Q-switched Nd:YAG nanosecond green laser pulses. The intensity dependent nonlinear absorption studies revealed a switch over in the nonlinear behaviour from saturable absorption (SA) to reverse saturable absorption (RSA) behaviour. SA occurs due to ground state bleaching at comparatively lower laser irradiances serving the need for Q-switching and optical communications. The RSA trait at higher laser irradiance is attributed to sequential two-photon absorption which serves as the platform for optical limiting behaviour prompting laser safety and effective photothermal therapy applications. The strong mid-visible and UV absorption promotes the availability of multiple energy bands for energy transitions of excited state absorption (ESA). Enhanced local fields due to localized surface plasmon resonance effect, structural defects, hierarchical morphology, increased absorption cross-section and plasmon induced energy transfer promotes robust ESA process. These tunable nonlinear optical properties make Au-rGO-MoS2 hybrid promising futuristic candidates for applications in nonlinear photonic devices, ultrafast optical switches and all-optical signal processing systems.

Due to their extended p-orbital delocalization, conjugated polymers absorb light in the range of visible–NIR frequencies. We attempt to exploit this property to create materials that compete with inorganic semiconductors in photovoltaic and light-emitting materials. Beyond competing for applications in photonic devices, organic conjugated compounds, polymers, and small molecules have also been extended to biomedical applications like phototherapy and biodetection. Recent research on conjugated polymers has focused on bioapplications based on the absorbed light energy conversions in electric impulses, chemical energy, heat, and light emission. In this review, we describe the working principles of those photonic devices that have been applied and researched in the field of biomaterials. [ABSTRACT FROM AUTHOR]

Highlights An overview of the superhydrophobic surface -assisted strategies for fabricating microspheres and supraparticles are presented. The applications of microspheres and supraparticles fabricated using SHS-assisted strategies are discussed in detail. NCrucial challenges facing the development of microspheres and supraparticles fabricated through SHS-assisted strategies are analysed.

New emerging low‐dimensional such as 0D, 1D, and 2D nanomaterials have attracted tremendous research interests in various fields of state‐of‐the‐art electronics, optoelectronics, and photonic applications due to their unique structural features and associated electronic, mechanical, and optical properties as well as high‐throughput fabrication for large‐area and low‐cost production and integration. Particularly, photodetectors which transform light to electrical signals are one of the key components in modern optical communication and developed imaging technologies for whole application spectrum in the daily lives, including X‐rays and ultraviolet biomedical imaging, visible light camera, and infrared night vision and spectroscopy. Today, diverse photodetector technologies are growing in terms of functionality and performance beyond the conventional silicon semiconductor, and low‐dimensional nanomaterials have been demonstrated as promising potential platforms. In this review, the current states of progress on the development of these nanomaterials and their applications in the field of photodetectors are summarized. From the elemental combination for material design and lattice structure to the essential investigations of hybrid device architectures, various devices and recent developments including wearable photodetectors and neuromorphic applications are fully introduced. Finally, the future perspectives and challenges of the low‐dimensional nanomaterials based photodetectors are also discussed. [ABSTRACT FROM AUTHOR]

Highlights: An overview of the superhydrophobic surface -assisted strategies for fabricating microspheres and supraparticles are presented. The applications of microspheres and supraparticles fabricated using SHS-assisted strategies are discussed in detail. NCrucial challenges facing the development of microspheres and supraparticles fabricated through SHS-assisted strategies are analysed. Superhydrophobic surface (SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them to retain spherical shapes, and the low adhesion of SHS facilitates easy droplet collection when tilting the substrate. These characteristics make SHS suitable for a wide range of applications. One particularly promising application is the fabrication of microsphere and supraparticle materials. SHS offers a distinct advantage as a universal platform capable of providing customized services for a variety of microspheres and supraparticles. In this review, an overview of the strategies for fabricating microspheres and supraparticles with the aid of SHS, including cross-linking process, polymer melting, and droplet template evaporation methods, is first presented. Then, the applications of microspheres and supraparticles formed onto SHS are discussed in detail, for example, fabricating photonic devices with controllable structures and tunable structural colors, acting as catalysts with emerging or synergetic properties, being integrated into the biomedical field to construct the devices with different medicinal purposes, being utilized for inducing protein crystallization and detecting trace amounts of analytes. Finally, the perspective on future developments involved with this research field is given, along with some obstacles and opportunities. [ABSTRACT FROM AUTHOR]

Owing to their unique tunable optical properties, chalcogenide phase change materials are increasingly being investigated for optics and photonics applications. However, in situ characterization of their phase transition characteristics is a capability that remains inaccessible to many researchers. Herein, a multifunctional silicon microheater platform capable of in situ measurement of structural, kinetic, optical, and thermal properties of these materials is introduced. The platform can be fabricated leveraging industry‐standard silicon foundry manufacturing processes. This platform is fully open‐sourced, including complete hardware design and associated software codes. [ABSTRACT FROM AUTHOR]

Diffractive optical neural networks (DONNs) are emerging as high‐throughput and energy‐efficient hardware platforms to perform all‐optical machine learning (ML) in machine vision systems. However, the current demonstrated applications of DONNs are largely image classification tasks, which undermine the prospect of developing and utilizing such hardware for other ML applications. Herein, the deployment of an all‐optical reconfigurable DONNs system for scientific computing is demonstrated numerically and experimentally, including guiding two‐dimensional quantum material synthesis, predicting the properties of two‐dimensional quantum materials and small molecular cancer drugs, predicting the device response of nanopatterned integrated photonic power splitters, and the dynamic stabilization of an inverted pendulum with reinforcement learning. Despite a large variety of input data structures, a universal feature engineering approach is developed to convert categorical input features to images that can be processed in the DONNs system. The results open up new opportunities for employing DONNs systems for a broad range of ML applications. [ABSTRACT FROM AUTHOR]

Diffractive optical neural networks (DONNs) are emerging as high‐throughput and energy‐efficient hardware platforms to perform all‐optical machine learning (ML) in machine vision systems. However, the current demonstrated applications of DONNs are largely image classification tasks, which undermine the prospect of developing and utilizing such hardware for other ML applications. Herein, the deployment of an all‐optical reconfigurable DONNs system for scientific computing is demonstrated numerically and experimentally, including guiding two‐dimensional quantum material synthesis, predicting the properties of two‐dimensional quantum materials and small molecular cancer drugs, predicting the device response of nanopatterned integrated photonic power splitters, and the dynamic stabilization of an inverted pendulum with reinforcement learning. Despite a large variety of input data structures, a universal feature engineering approach is developed to convert categorical input features to images that can be processed in the DONNs system. The results open up new opportunities for employing DONNs systems for a broad range of ML applications.

Owing to their unique tunable optical properties, chalcogenide phase change materials are increasingly being investigated for optics and photonics applications. However, in situ characterization of their phase transition characteristics is a capability that remains inaccessible to many researchers. Herein, a multifunctional silicon microheater platform capable of in situ measurement of structural, kinetic, optical, and thermal properties of these materials is introduced. The platform can be fabricated leveraging industry‐standard silicon foundry manufacturing processes. This platform is fully open‐sourced, including complete hardware design and associated software codes.

In recent years, with the further ministration of the semiconductor device in integrated circuits, power consumption and data transmission bandwidth have become insurmountable obstacles. As an integrated technology, photonic integrated circuits (PICs) have a promising potential in the post‐Moore era with more advantages in data processing, communication, and diversified sensing applications for their ultra‐high process speed and low power consumption. Silicon photonics is believed to be an encouraging solution to realize PICs because of the mature CMOS process. The past decades have witnessed a huge growth in silicon PICs. However, there is still a demand for the development of silicon PICs to enable powerful chip‐scale systems and new functionalities. In this paper, a review of the photonic components, functional blocks, and emerging applications for PICs is offered. The common photonic components are classified into several sections, including on‐chip light sources, fiber‐to‐chip couplers, photonic resonators, waveguide‐based sensors, on‐chip photodetectors, and modulators. The functional blocks of the PICs mentioned in this review are photonic memories and photonic neural networks. Finally, the paper concludes with emerging applications for further study. [ABSTRACT FROM AUTHOR]

Versatile optical devices with smaller space footprint are crucial for integrated optics. In this work, we design a dual-waveguide power splitter with adjustable splitting ratio depending on the input ports. The modulated gain and loss are imposed on two waveguides to nullify the non-adiabatic coupling using non-Hermitian shortcut to adiabaticity technique. Simulation results reveal that the length of the power splitter can be shortened to about one ninth compared to the one along the adiabatic path, meanwhile, the proposed splitter has good robustness against possible fabrication errors. [ABSTRACT FROM AUTHOR]

The recently proposed concept of graphene photodetectors offers remarkable properties such as unprecedented compactness, ultrabroadband detection, and an ultrafast response speed. However, owing to the low optical absorption of pristine monolayer graphene, the intrinsically low responsivity of graphene photodetectors significantly hinders the development of practical devices. To address this issue, numerous efforts have thus far been made to enhance the light-graphene interaction using plasmonic structures. These approaches, however, can be significantly advanced by leveraging the other critical aspect of graphene photoresponsivity enhancement-electrical junction control. It has been reported that the dominant photocarrier generation mechanism in graphene is the photothermoelectric (PTE) effect. Thus, the two energy conversion mechanisms involved in the graphene photodetection process are light-to-heat and heat-to-electricity conversions. In this work, we propose a meticulously designed device architecture to simultaneously enhance the two conversion efficiencies. Specifically, a gap plasmon structure is used to absorb a major portion of the incident light to induce localized heating, and a pair of split gates is used to produce a p-n junction in graphene to augment the PTE current generation. The gap plasmon structure and the split gates are designed to share common key components so that the proposed device architecture concurrently realizes both optical and electrical enhancements. We experimentally demonstrate the dominance of the PTE effect in graphene photocurrent generation and observe a 25-fold increase in the generated photocurrent compared to the un-enhanced cases. While further photocurrent enhancement can be achieved by applying a DC bias, the proposed device concept shows vast potential for practical applications.

Melanin comes from a wide range of sources. It can be isolated and characterized from some plants, animals and microorganisms, and can also be simply polymerized by dopamine. It has many biological properties such as antioxidant, ultraviolet shielding and bacteriostasis. Based on the above characteristics, the addition of melanin to film-forming materials can improve the relevant physical properties and functional properties of the film. In this article, the structure and properties of melanin were briefly introduced, and then the advantages and related research progress of melanin as a functional filler in the field of composite film were summarized.

In recent years, tremendous attention has been paid to the investigation of single‐element 2D materials. These 2D materials mainly consist of elements from group IV and group V such as silicene, phosphorene, and antimonene. Together with other four elements from groups III and VI, they are classified as 2D Xenes and exhibit rich optical and optoelectronic properties such as broadband optical response, strong nonlinearity, ultrafast recovery time, and layer‐dependent bandgap. 2D Xenes can be easily integrated with microfibers and other optical platforms. On the basis of their attracting characteristics, 2D Xenes have been utilized in various functional devices. In this review, the optical and optoelectronic properties of the most intensively studied 2D Xenes are introduced. Their applications in photonic devices including all‐optical modulators, wavelength converters, ultrafast lasers, and photodetectors are explicitly explored. Finally, the challenges and future perspectives of photonic devices based on 2D Xenes are discussed. [ABSTRACT FROM AUTHOR]

The ultrafast response and broadband absorption of all-optical graphene switches are highly desirable features for on-chip photonic switching. However, because graphene is an atomically thin material, its absorption of guided optical modes is relatively low, resulting in high saturation thresholds and switching energies for these devices. To boost the absorption of graphene, we present a practical design of an electrically-biased all-optical graphene switch that is integrated into silicon slot waveguides, which strongly confine the optical mode in the slotted region and enhance its interaction with graphene. Moreover, the design incorporates a silicon slab layer and a hafnia dielectric layer to electrically tune the saturation threshold and the switching energy of the device by applying direct-current voltages of < 0.5 V. Using this device, a high extinction ratio of 10.3 dB, a low insertion loss of < 0.7 dB, and an ultra-efficient switching energy of 79 fJ/bit at 0.23 V bias are attainable for a 40 µ m long switch. The reported performance metrics for this device are highly promising and are expected to serve the needs of next-generation photonic computing systems. [ABSTRACT FROM AUTHOR]

The electronic structure, dipole moment (µ), average polarizability (< α >), anisotropie (Δα), first molecular hyperpolarizability (βmol), molar refractivity (κ) , HOMO energy (EHOMO), LUMO energy (ELUMO), energy gap (Egap), ionization potential (IP), electron affinity (EA), electronegativity (ς) , chemical potential (δ) , chemical hardness (ϑ) , chemical softness (σ) , and electrophilicity index (ω) , , total electronic energy (E0), zero point vibrational energy (zpve), thermal energy (E), Molar heat capacity at constant volume (CV), entropy (S), total electronic energy without Zero point correction (E1), total electronic energy with Zero point correction (E2), total electronic energy with thermal Energies (E3), total electronic energy with Enthalpies (E4), total electronic energy with thermal free Energies (E5), Volume (V), average Electric field (E), Polarization density (P), electric susceptibility (χ), relative dielectric constant (ɛr), dielectric constant (ɛ), refractive index (ɳ) and displacement vector (D) of doped and undoped pentacene and petracene have been determined by using Restricted Hartree–Fock (RHF), and Density Functional Theory (DFT) methods (B3LYP, WB97XD and BPBE) with the cc-PVDZ basis set. The aim of this work is to research new materials that can have applications in the fields of linear and nonlinear optics, electronics and optoelectronics. The results obtained from B3LYP, WB97XD and BPBE level show that the molecules are good semiconductor with very good optoelectronic properties and may have application in photonic, electronic, optoelectronics, organic light-emitting diode (OLEDs) and thin films. The large values of the refractive index (ɳ) and electric susceptibility (χ) of these molecules allow us to conclude that these molecules have good linear and nonlinear optical, electronic optoelectronic and photonic applications. [ABSTRACT FROM AUTHOR]

Films and patterns of 3D-oriented metal-organic frameworks (MOFs) afford well-ordered pore structures extending across centimeter-scale areas. These macroscopic domains of aligned pores are pivotal to enhance diffusion along specific pathways and orient functional guests. The anisotropic properties emerging from this alignment are beneficial for applications in ion conductivity and photonics. However, the structure of 3D-oriented MOF films and patterns can rapidly degrade under humid and acidic conditions. Thus, more durable 3D-ordered porous systems are desired for practical applications. Here, oriented porous polymer films and patterns are prepared by using heteroepitaxially oriented N 3 -functionalized MOF films as precursor materials. The film fabrication protocol utilizes an azide-alkyne cycloaddition on the Cu 2 (AzBPDC) 2 DABCO MOF. The micropatterning protocol exploits the X-ray sensitivity of azide groups in Cu 2 (AzBPDC) 2 DABCO, enabling selective degradation in the irradiated areas. The masked regions of the MOF film retain their N 3 -functionality, allowing for subsequent cross-linking through azide-alkyne coupling. Subsequent acidic treatment removes the Cu ions from the MOF, yielding porous polymer micro-patterns. The polymer has high chemical stability and shows an anisotropic fluorescent response. The use of 3D-oriented MOF systems as precursors for the fabrication of oriented porous polymers will facilitate the progress of optical components for photonic applications., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

The realization of semiconductor heterostructures marks a significant advancement beyond silicon technology, driving progress in high-performance optoelectronics and photonics, including high-brightness light emitters, optical communication, and quantum technologies. In less than a decade since 1997, nanowires research has expanded into new application-driven areas, highlighting a significant shift toward more challenging and exploratory research avenues. It is therefore essential to reflect on the past motivations for nanowires development, and explore the new opportunities it can enable. The advancement of heterogeneous integration using dissimilar substrates, materials, and nanowires-semiconductor/electrolyte operating platforms is ushering in new research frontiers, including the development of perovskite-embedded solar cells, photoelectrochemical (PEC) analog and digital photonic systems, such as PEC-based photodetectors and logic circuits, as well as quantum elements, such as single-photon emitters and detectors. This review offers rejuvenating perspectives on the progress of these group-III nitride nanowires, aiming to highlight the continuity of research toward high impact, use-inspired research directions in photonics and optoelectronics., (© 2024 Wiley‐VCH GmbH.)

Programmable and reconfigurable optics hold significant potential for transforming a broad spectrum of applications, spanning space explorations to biomedical imaging, gas sensing, and optical cloaking. The ability to adjust the optical properties of components like filters, lenses, and beam steering devices could result in dramatic reductions in size, weight, and power consumption in future optoelectronic devices. Among the potential candidates for reconfigurable optics, chalcogenide-based phase change materials (PCMs) offer great promise due to their non-volatile and analogue switching characteristics. Although PCM have found widespread use in electronic data storage, these memory devices are deeply sub-micron-sized. To incorporate phase change materials into free-space optical components, it is essential to scale them up to beyond several hundreds of microns while maintaining reliable switching characteristics. This study demonstrated a non-mechanical, non-volatile transmissive filter based on low-loss PCMs with a 200 × 200 µm 2 switching area. The device/metafilter can be consistently switched between low- and high-transmission states using electrical pulses with a switching contrast ratio of 5.5 dB. The device was reversibly switched for 1250 cycles before accelerated degradation took place. The work represents an important step toward realizing free-space reconfigurable optics based on PCMs., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

We propose and demonstrate an accurate method of measuring the effective refractive index of silicon-on-insulator waveguides. By conducting the combined analysis to the troughs' wavelength in spectra of Mach–Zehnder interferometers on chip. The wavelength-dependent and temperature-dependent effective refractive index of the fabricated waveguides are measured experimentally, and obtained the thermo-optic coefficient of silicon-on-insulator waveguides is about 2×10−4 /℃ in the 1550 nm communication band. The maximum measurement error for effective and group refractive index respectively are 1.5×10−5 and 1.5×10−3 obtained by numerical simulation. And an improved method for taking value of the free spectral range was discussed to obtain a more accurate group refractive index. It proves a fast and lost-cost measurement way to evaluate key optical parameters of waveguide, which can indicate the quality of fabrication process and optimize photonic components. [Display omitted] • We demonstrate an accurate method of measuring the effective refractive index of silicon-on-insulator waveguides. • An improved method for taking value of the free spectral range is discussed to obtain a more accurate group refractive index. • The method proves a fast and lost-cost measurement way to evaluate the optical and geometric parameters of waveguides. [ABSTRACT FROM AUTHOR]

Notwithstanding the great scientific−technological interest in lithium niobate (LiNbO3), its optical bandgap Egap has been subject of intense discussion. So far, the literature exhibits different Egap values spanning over about 2 eV and comprises a mixture of compositions, structures, and theoretical methods − not always clearly indicated or discussed. In view of that, this work presents a thorough investigation of the Egap (at room-temperature and in the ∼80–800 K temperature range) of the congruent ferroelectric LiNbO3 (Z-cut) single crystal.

Passive optical tapping can be implemented by stacking multiple layers of polydimethylsiloxane (PDMS), which is used as planar waveguides for the transmission and capturing of light. Once the main waveguide is installed in the communications system, each additional stacked waveguide represents an optical sniffer where it is possible to intercept the data from an input optical fibre, allowing the information to also flow to the output fibre unnoticeably from the point of view of the transmitter. The waveguides can be stacked or removed, making it a dynamic device that overcomes the limitations of previous designs, and the optical sniffer shows fixed implementation. In addition, it is demonstrated that PDMS is a versatile material that permits the control of the coupling of light among the waveguides, depending on its properties, and the thickness of each waveguide is also critical for the performance of the device. Furthermore, the experimental results are supported with a theoretical analysis that permits better understanding of the performance of the device, whose use can be extended to other applications, such as a passive optical hub or a signal combiner/splitter.

2D materials are emerging as ideal candidates for fundamental investigations and new technologies due to their unique optoelectronic properties. Giant nonlinear susceptibility and perfect phase matching in 2D materials lead to extraordinary nonlinear light matter interactions, thus enabling several potential applications and fundamental scientific discoveries in nonlinear optics. For instance, second harmonic generation in 2D materials play an important role in optical devices such as, lasers, tunable waveguides, electro‐optic modulators, and switches. This review will discuss optical harmonic generation (OHG) processes, various characterization modes, and tuning techniques in 2D materials. The future prospectives for OHG in 2D materials is discussed. The extremely promising attributes of combining nonlinear optics and 2D materials is becoming a highly important multidisciplinary field. [ABSTRACT FROM AUTHOR]

Anisotropic 2D materials are promising building blocks for future photonic and optoelectronic devices due to their low structural symmetry and in‐plane optical anisotropy. This review systematically summarizes the crystalline structure, growth dynamics, optical anisotropy and their modulation strategies, and the corresponding photonic applications for emerging anisotropic 2D materials. First, the physical properties and crystalline structures of typical anisotropic 2D materials are briefly introduced. After that, special attention is paid to the growth mechanism of low‐symmetry lattices, where the competition between different growth modes determines the crystal morphologies. Then, the physical principles of anisotropic optical absorption, photoluminescence, Raman scattering, photodetection, and nonlinear response are discussed based on recent scientific advances. The discussion on the techniques to modify the intrinsic in‐plane anisotropy, along with the possibility of introducing optical anisotropy to the isotropic materials, add a new degree of freedom to the control over their optical properties. The review of application prospects also helps bridge the gap between the scientific exploration of novel anisotropic materials and the development of polarization‐sensitive photonic devices. The discussions in this review will push forward the scientific frontier in the crystalline growth and anisotropy control of anisotropic 2D materials. [ABSTRACT FROM AUTHOR]

In this study, metallic nanoislands were prepared by thermal annealing of gold thin film produced by vacuum evaporation on a glass substrate to investigate the surface-enhanced Raman scattering (SERS) effect on them. The influence of the analyte on the enhancement factor of SERS was studied with riboflavin and rhodamine 6G dye. Two laser excitation sources at 532 and 633 nm wavelengths were used for SERS measurements. We found that the enhancement factors of the gold nanoisland SERS substrates were influenced by the analytes' adsorption tendency onto their surfaces. The SERS amplification was also found to be dependent on the electronic structure of the molecules; higher enhancement factors were obtained for rhodamine 6G with 532 nm excitation, while for riboflavin the 633 nm source performed better. [ABSTRACT FROM AUTHOR]

A series of samarium ions (Sm3+) activated barium sodium niobate (Ba2NaNb5O15) samples have been successfully synthesized via employing a solid‐state reaction technique. Single phase, crystalline tetragonal Ba2NaNb5O15 were formed and the crystallite size of the prepared sample varied with doping of Sm3+ ions. The scanning electron microscopy (SEM) images of Ba2NaNb5O15:Sm3+ illustrate that the particles possess a non‐uniform spherical structure with some agglomeration. The prepared Ba2NaNb5O15:Sm3+ phosphors were efficiently excited with near‐ultraviolet (n‐UV) (406 nm) and emit strong visible emission peaks in the range 550–725 nm. The phenomenon of concentration quenching was detected after x = 0.10 mol of Sm3+ ions concentration for Ba2NaNb5O15, which arises due to non‐radiative energy transfer through dipole–dipole interaction among activator ions. Colour coordinates (0.586, 0.412) for the optimized phosphor lies in the visible reddish orange region. A bi‐exponential decay behaviour was observed for the photoluminescence decay curve of the optimized phosphor sample with an average decay time in milliseconds. The temperature dependent emission intensity confirms that the Ba2−xNaNb5O15:xSm3+ (x = 0.10 mol) phosphor exhibits adequate thermal stability having high value of activation energy (ΔE = 0.201 eV). The comprehensive study and analysis of the as‐prepared samples suggest that the intense reddish orange emitting thermally stable Ba2NaNb5O15:Sm3+ phosphor can act as a potential luminescent material in phosphor coated lighting, solar cells and other photonic devices. [ABSTRACT FROM AUTHOR]

Cholesteric liquid crystals (CLCs) are a major class of photonic materials that display selective reflection properties arising from their helical ordering. The temperature response of CLCs, comprising dynamic reflection color changes upon variation of temperature, is exploited using material systems consisting of small mesogenic molecules, polymer‐dispersed liquid crystals (PDLCs), polymer‐stabilized liquid crystals (PSLCs), or liquid‐crystalline polymers. Taking advantage of the easy processability and flexibility of the molecular design, these temperature‐responsive CLCs are fabricated into different forms of photonic devices, including cells, coatings, free‐standing films, and 3D objects. Temperature‐responsive devices developed from CLCs are integrated for application in temperature sensors, energy‐saving smart windows, smart labels, actuators, and adding aesthetically pleasing features to common objects. Herein, the device capabilities of the different material systems of temperature‐responsive CLCs are summarized: small mesogenic molecules, PDLCs, PSLCs, and CLC polymers. For each system, examples of different device forms are presented, with their temperature responsiveness and the underlying mechanisms discussed. In addition, the potential of each material system for future device applications and product developments is envisioned.

The popularity of polyhedral oligomeric silsesquioxanes (POSS) for use in hybrid organic–inorganic materials and devices has grown in the past two decades due to desirable properties such as good thermal stability and biocompatibility, as well as their potential to be functionalized for a wide range of applications, from polymer composites to optoelectronics. Herein, the role of POSS for photonic applications, including sensing, bioimaging, and optoelectronic devices, is summarized. Functionalized POSS building blocks commonly incorporated with luminescent materials are identified, and areas of potential growth within the field are discussed. The addition of POSS to light‐emitting materials is widely shown to prevent aggregation in organic lumophores and inorganic nanocrystals, leading to reduced photoluminescence quenching. The POSS unit is also capable of acting as a passivating agent for nanocrystals and thin films, improving the emission quantum yields of photoluminescent materials and devices. POSS therefore offers the potential to enhance both the functional and photonic properties of cutting‐edge hybrid technologies.

We propose a method to analyze the performance variability caused by fabrication uncertainty in photonic circuits with a large number of correlated parameters. By combining a sparse polynomial chaos expansion model with dimensionality reduction in the form of Karhunen-Loève transform and principal component analysis, we demonstrate the stochastic analysis of the transfer function of cascaded Mach-Zehnder interferometers with up to 38 correlated uncertain parameters. [ABSTRACT FROM AUTHOR]

Liquid crystal (LC) planar optical elements (POEs) based on photoalignment technology have emerged as a promising approach to manipulating light in various ways. Owing to the high diffraction efficiency, polarization sensitive, and simple fabrication process, LC POEs have found enormous applications in display and photonic devices. In this review, we analyze the Pancharatnam-Berry (PB) phase, polarization holography and photoalignment mechanism, and present a variety of applications in display and photonic devices including optically rewritable liquid crystal device, LC grating, LC lens, LC near-eye displays, LC encryption and LC robots. Although photoalignment-based LC POEs have greatly promoted the development of optics in academia and engineering, there are still many issues that need to be resolved, such as small field of view, uneven imaging quality, chromatic aberration, etc. Due to the ultrathin nature of LC POEs, they can be seamlessly integrated into modern displays, wearables, and many other systems. This review finally concludes with a summary and perspectives on the challenges and opportunities for the applications of LC POEs. It is believed that the developments introduced here can provide directions for future research, and present potential opportunities to encourage future research in the applications of LC POEs. • The working principles of LC, PB phase and photoalignment are introduced. • Applications of LC POEs in display and photonic devices are presented. • This article briefly sorts out and summarizes the latest results of LC POEs. [ABSTRACT FROM AUTHOR]