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1. Epitaxial mid-IR nanophotonic optoelectronics

   https://doi.org/10.1063/5.0086774  

   Nordin, L.; Wasserman, D. (May 2022, Applied Physics Letters)

   There are a range of fundamental challenges associated with scaling optoelectronic devices down to the nano-scale, and the past decades have seen significant research dedicated to the development of sub-diffraction-limit optical devices, often relying on the plasmonic response of metal structures. At the longer wavelengths associated with the mid-infrared, dramatic changes in the optical response of traditional nanophotonic materials, reduced efficiency optoelectronic active regions, and a host of deleterious and/or parasitic effects makes nano-scale optoelectronics at micro-scale wavelengths particularly challenging. In this Perspective, we describe recent work leveraging a class of infrared plasmonic materials, highly doped semiconductors, which not only support sub-diffraction-limit plasmonic modes at long wavelengths, but which can also be integrated into a range of optoelectronic device architectures. We discuss how the wavelength-dependent optical response of these materials can serve a number of different photonic device designs, including dielectric waveguides, epsilon-near-zero dynamic optical devices, cavity-based optoelectronics, and plasmonic device architectures. We present recent results demonstrating that the highly doped semiconductor class of materials offers the opportunity for monolithic, all-epitaxial, device architectures out-performing current state of the art commercial devices, and discuss the perspectives and promise of these materials for infrared nanophotonic optoelectronics. 

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2. An ionic Fe-based metal–organic-framework with 4′-pyridyl-2,2′:6′,2′′-terpyridine for catalytic hydroboration of alkynes

   https://doi.org/10.1039/D2RA08040K  

   Zhang, Guoqi; Zheng, Shengping; Neary, Michelle C. (January 2023, RSC Advances)

   An ionic metal–organic-framework (MOF) containing nanoscale channels was readily assembled from ditopic 4′-pyridyl-2,2′:6′,2′′-terpyridine (pytpy) and a simple iron( ii ) salt. X-ray structural analysis revealed a two-dimensional grid-like framework assembled by classic octahedral (pytpy) 2 Fe II cations as linkers (with pytpy as a new ditopic pyridyl ligand) and octa-coordinate FeCl 2 centers as nodes. The layer-by-layer assembly of the 2-D framework resulted in the formation of 3-D porous materials consisting of nano-scale channels. The charges of the cationic framework were balanced with anionic Cl 3 FeOFeCl 3 in its void channels. The new Fe-based MOF material was employed as a precatalyst for syn -selective hydroboration of alkynes under mild, solvent-free conditions in the presence of an activator, leading to the synthesis of a range of trans -alkenylboronates in good yields. The larger scale applicability and recyclability of the new MOF catalyst was further explored. This represents a rare example of an ionic MOF material that can be utilized in hydroboration catalysis. 

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3. New paradigms in materials and devices for hybrid electro-optics and optical rectification

   https://doi.org/10.1117/12.2595638  

   Johnson, Lewis E.; Elder, Delwin L.; Xu, Huajun; Hammond, Scott W.; Benight, Stephanie J.; O'Malley, Kevin; Robinson, Bruce H.; Dalton, Larry R. (August 2021, Molecular and Nano Machines IV)

   Sekkat, Zouheir; Omatsu, Takashige (Ed.)

   We review recent transformative advances in materials design, synthesis, and processing as well as device engineering for the utilization of organic materials in hybrid electro-optic (EO) and optical rectification (OR) technologies relevant to telecommunications, sensing, and computing. End-to-end (from molecules to systems) modeling methods utilizing multi-scale computation and theory permit prediction of the performance of novel materials in nanoscale device architectures including those involving plasmonic phenomena and architectures in which interfacial effects play a dominant role. Both EO and OR phenomenon require acentric organization of constituent active molecules. The incumbent methodology for achieving such organization is electric field poling, where chromophore shape, dipole moment, and conformational flexibility play dominant roles. Optimized chromophore design and control of the poling process has already led to record-setting advances in electro-optic performance, e.g., voltage-length performance of < 50 volt-micrometer, bandwidths > 500 GHz, and energy efficiency < 70 attojoule/bit. They have also led to increased thermal stability, low insertion loss and high signal quality (BER and SFDR). However, the limits of poling in the smallest nanophotonic devices—in which extraordinary optical field densities can be achieved—has stimulated development of alternatives based on covalent coupling of modern high-performance chromophores into ordered nanostructures. Covalent coupling enables higher performance, greater scalability, and greater stability and is especially suited for the latest nanoscale architectures. Recent developments in materials also facilitate a new technology—transparent photodetection based on optical rectification. OR does not involve electronic excitation, as is the case with conventional photodiodes, and as such represents a novel detection mechanism with a greatly reduced noise floor. OR already dominates at THz frequencies and recent advances will enable superior performance at GHz frequencies as well. 

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4. Block‐Copolymer‐Architected Materials in Electrochemical Energy Storage

   https://doi.org/10.1002/smsc.202300074  

   Werner, Jörg G.; Li, Yuanzhi; Wiesner, Ulrich (November 2023, Small Science)

   The multiscale architecture of electrochemical energy storage (EES) materials critically impacts device performance, including energy, power, and durability. The pore space of nano‐ to macrostructured electrodes determines mass transport within the electrolyte and defines the effective energy density. The dimensions of the active charge‐storing materials can increase stability during cycling by accommodating strains from electrochemical–mechanical coupling while also defining surface area that increases capacitive charge storage, decreases charge‐transfer resistance, but also leads to low efficiency and degradation from interfacial reactions. Thus, elucidating and developing a fundamental understanding of these correlations requires materials with precisely tunable nanoscale architectures. Herein, approaches that take advantage of the nanoscale control offered by block copolymer (BCP) self‐assembly are reviewed and insights gained from associated nanoscale phenomena observed in EES are highlighted. Systematic studies that use custom‐tailored BCPs to reveal fundamental nanostructure–property–performance relationships are emphasized. Importantly, most reports of nanostructured materials utilize low loadings and thin electrodes and results represent mass transfer limitations at the particle scale. However, as cell‐level performance involves mass transport over 10–100s of micrometers, recently emerging BCP‐based processes are further highlighted, leading to hierarchical meso/macroporous materials needed for creating multiscale structure–performance relationships and next‐generation energy storage material architectures. 

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5. The renaissance of lateral power devices for high voltage applications

   https://doi.org/10.1063/5.0278883  

   Yang, Zineng; Qin, Yuan; Zhang, Yuhao (September 2025, APL Electronic Devices)

   Power semiconductor devices, spanning blocking voltages from a few volts to tens of thousands of volts, are critical for efficient energy conversion in numerous applications and serve as key enablers of carbon neutrality. These devices can be realized in either vertical or lateral architectures, with the former preferred for high-power discrete devices and the latter offering high switching speeds and monolithic circuit integration. While lateral structures have long been utilized in low- and medium-voltage applications, recent advancements in multidimensional device architectures and (ultra-)wide-bandgap semiconductor materials have revitalized their potential for high-voltage applications. Multidimensional architectures, such as superjunction and multichannel designs, enable uniform electric field distribution for voltage scaling and, at the same time, boost carrier concentrations to enhance current capacity. The application of these architectures in gallium nitride and gallium oxide has led to the demonstration of multi-kilovolt lateral devices with diverse designs, achieving breakdown voltages exceeding 10 000 V, average electric fields up to 4.7 MV/cm, high-temperature operation up to 250 °C, and specific on-resistances at least 2–3 times lower than similarly rated vertical devices. Such advantages can be further enhanced through the implementation of monolithic bidirectional devices, a unique capability of the lateral architecture that enables the replacement of four vertical devices. This review provides an overview of multidimensional high-voltage lateral devices, emphasizing their fundamental device physics to inspire further applications across various material systems. The theoretical performance limits of multidimensional lateral devices are also analyzed. In addition, we discuss critical knowledge gaps that must be addressed for industrial adoption, highlighting emerging research opportunities in this rapidly evolving field. 

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