Spintronic Pathways in a Nonconjugated Radical Polymer Glass.

Radical chemistries have attracted burgeoning attention due to their intriguing technological applications in organic electronics, optoelectronics, and magneto-responsive systems. However, the potential of these magnetically active glassy polymers to transport spin-selective currents has not been demonstrated. Here, the spin-transport characteristics of the radical polymer poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) (PTEO) allow for sustained spin-selective currents when incorporated into typical device geometries with magnetically polarized electrodes.

Critical Mineral Separations: Opportunities for Membrane Materials and Processes to Advance Sustainable Economies and Secure Supplies.

Sustainable energy solutions and electrification are driving increased demand for critical minerals. Unfortunately, current mineral processing techniques are resource intensive, use large quantities of hazardous chemicals, and occur at centralized facilities to realize economies of scale. These aspects of existing technologies are at odds with the sustainability goals driving increased demand for critical minerals.

Conductive Glassy Nonconjugated Open-Shell Radical Polymer with Organosulfur Backbone for Macroscopic Conductivity.

Nonconjugated organic radicals with an open-shell radical active group exhibit unique functionality due to their radical pendant site. Compared with the previously studied doped conjugated polymers, radical polymers reveal superior processability, stability, and optical properties. Despite the success of organic radical polymer conductors based on the TEMPO radicals, it still requires potential design substitutions to meet the fundamental limits of charge transport in the radical polymer.

Large Room-Temperature Magnetoresistance in a High-Spin Donor-Acceptor Conjugated Polymer.

Open-shell conjugated polymers (CPs) offer new opportunities for the development of emerging technologies that utilize the spin degree of freedom. Their light-element composition, weak spin-orbit coupling, synthetic modularity, high chemical stability, and solution-processability offer attributes that are unavailable from other semiconducting materials. However, developing an understanding of how electronic structure correlates with emerging transport phenomena remains central to their application.

Anomalous magnetoresistance in a nonconjugated radical polymer glass.

Macromolecules bearing open-shell entities offer unique transport properties for both electronic and spintronic devices. This work demonstrates that, unlike their conjugated polymer counterparts, the charge carriers in radical polymers (i.e.

Enhanced Electron Transport in Nonconjugated Radical Oligomers Occurs by Tunneling.

Incorporating temperature- and air-stable organic radical species into molecular designs is a potentially advantageous means of controlling the properties of electronic materials. However, we still lack a complete understanding of the structure-property relationships of organic radical species at the molecular level. In this work, the charge transport properties of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) radical-containing nonconjugated molecules are studied using single-molecule charge transport experiments and molecular modeling.

Bridging the Monomer to Polymer Gap in Radical Polymer Design.

Radical polymers bearing open-shell moieties at pendant sites exhibit unique redox and optoelectronic properties that are promising for many organic electronic applications. Nevertheless, gaps remain in relating the electronic properties of repeat units, which can be easily calculated, to the condensed-phase charge transport behaviors of these materials. To address this gap, we have performed the first quantum chemical study on a broad swathe of radical polymer design space that explicitly includes the coupling between polymer constraints and radical-mediated intramolecular charge transfer.

Tailoring Molecular-Scale Contact at the Perovskite/Polymeric Hole-Transporting Material Interface for Efficient Solar Cells.

Perovskite solar cells (PSCs) have delivered a power conversion efficiency (PCE) of more than 25% and incorporating polymers as hole-transporting layers (HTLs) can further enhance the stability of devices toward the goal of commercialization. Among the various polymeric hole-transporting materials, poly(triaryl amine) (PTAA) is one of the promising HTL candidates with good stability; however, the hydrophobicity of PTAA causes problematic interfacial contact with the perovskite, limiting the device performance. Using molecular side-chain engineering, a uniform 2D perovskite interlayer with conjugated ligands, between 3D perovskites and PTAA is successfully constructed.

Smart soft contact lenses for continuous 24-hour monitoring of intraocular pressure in glaucoma care.

Continuous monitoring of intraocular pressure, particularly during sleep, remains a grand challenge in glaucoma care. Here we introduce a class of smart soft contact lenses, enabling the continuous 24-hour monitoring of intraocular pressure, even during sleep. Uniquely, the smart soft contact lenses are built upon various commercial brands of soft contact lenses without altering their intrinsic properties such as lens power, biocompatibility, softness, transparency, wettability, oxygen transmissibility, and overnight wearability.

Circularly Recyclable Polymers Featuring Topochemically Weakened Carbon-Carbon Bonds.

Closed-loop circular utilization of plastics is of manifold significance, yet energy-intensive and poorly selective scission of the ubiquitous carbon-carbon (C-C) bonds in contemporary commercial polymers pose tremendous challenges to envisioned recycling and upcycling scenarios. Here, we demonstrate a topochemical approach for creating elongated C-C bonds with a bond length of 1.57∼1.

Radical Polymer-Based Organic Electrochemical Transistors.

Organic electrochemical transistors (OECTs) are an emerging platform for bioelectronic applications. Significant effort has been placed in designing advanced polymers that simultaneously transport both charge and ions (i.e.

Designing Donor-Acceptor Copolymers for Stable and High-Performance Organic Electrochemical Transistors.

Organic electrochemical transistors (OECTs) are oft-used for bioelectronic applications, and a variety of OECT channel materials have been developed in recent years. However, the majority of these materials are still limited by long-term performance and stability challenges. To resolve these issues, we implemented a next-generation design of polymers for OECTs.

High-Spin ( = 1) Blatter-Based Diradical with Robust Stability and Electrical Conductivity.

Triplet ground-state organic molecules are of interest with respect to several emerging technologies but usually show limited stability, especially as thin films. We report an organic diradical, consisting of two Blatter radicals, that possesses a triplet ground state with a singlet-triplet energy gap, Δ ≈ 0.4-0.

Electronic and Spintronic Open-Shell Macromolecules, ?

Open-shell macromolecules (i.e., polymers containing radical sites either along their backbones or at the pendant sites of repeat units) have attracted significant attention owing to their intriguing chemical and physical (e.

Electronic and Magnetic Properties of a Three-Arm Nonconjugated Open-Shell Macromolecule.

Nonconjugated radical polymers (i.e., macromolecules with aliphatic backbones that have stable open-shell sites along their pendant groups) have arisen as an intriguing complement to π-conjugated polymers in organic electronic devices and may prove to have superior properties in magneto-responsive applications.

Rapid, continuous projection multi-photon 3D printing enabled by spatiotemporal focusing of femtosecond pulses.

There is demand for scaling up 3D printing throughput, especially for the multi-photon 3D printing process that provides sub-micrometer structuring capabilities required in diverse fields. In this work, high-speed projection multi-photon printing is combined with spatiotemporal focusing for fabrication of 3D structures in a rapid, layer-by-layer, and continuous manner. Spatiotemporal focusing confines printing to thin layers, thereby achieving print thicknesses on the micron and sub-micron scale.

Ligand-Driven Grain Engineering of High Mobility Two-Dimensional Perovskite Thin-Film Transistors.

Controlling grain growth is of great importance in maximizing the charge carrier transport for polycrystalline thin-film electronic devices. The thin-film growth of halide perovskite materials has been manipulated via a number of approaches including solvent engineering, composition engineering, and post-treatment processes. However, none of these methods lead to large-scale atomically flat thin films with extremely large grain size and high charge carrier mobility.

Thermoelectric Performance of Lead-Free Two-Dimensional Halide Perovskites Featuring Conjugated Ligands.

Sn-based halide perovskites are promising for thermoelectric (TE) device applications because of their high electrical conductivity as well as the low thermal conductivity associated with their soft lattices. However, conventional three-dimensional Sn-based perovskites are not stable under typical TE device operating conditions. Here, we report a stable two-dimensional Sn-based perovskite for thermoelectric energy conversion by incorporating bulky conjugated ligands.

Molecular Design Features for Charge Transport in Nonconjugated Radical Polymers.

Conducting polymers based on open-shell radical moieties exhibit potentially advantageous processing, stability, and optical attributes compared with conventional doped conjugated polymers. Despite their ascendance, reported radical conductors have been based almost exclusively on (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO), which raises fundamental questions regarding the ultimate limits of charge transport in these materials and whether some of the deficiencies exhibited by contemporary materials are due to the choice of radical chemistry. To address these questions, we have performed a density functional theory (DFT) study of the charge transfer characteristics of a broad range of open-shell chemistries relevant to radical conductors, including p-type, n-type, and ambipolar open-shell chemistries.

Manipulating polymer composition to create low-cost, high-fidelity sensors for indoor CO monitoring.

Carbon dioxide (CO) has been linked to many deleterious health effects, and it has also been used as a proxy for building occupancy measurements. These applications have created a need for low-cost and low-power CO sensors that can be seamlessly incorporated into existing buildings. We report a resonant mass sensor coated with a solution-processable polymer blend of poly(ethylene oxide) (PEO) and poly(ethyleneimine) (PEI) for the detection of CO across multiple use conditions.

All-printed stretchable corneal sensor on soft contact lenses for noninvasive and painless ocular electrodiagnosis.

Electroretinogram examinations serve as routine clinical procedures in ophthalmology for the diagnosis and management of many ocular diseases. However, the rigid form factor of current corneal sensors produces a mismatch with the soft, curvilinear, and exceptionally sensitive human cornea, which typically requires the use of topical anesthesia and a speculum for pain management and safety. Here we report a design of an all-printed stretchable corneal sensor built on commercially-available disposable soft contact lenses that can intimately and non-invasively interface with the corneal surface of human eyes.

100th Anniversary of Macromolecular Science Viewpoint: Recent Advances and Opportunities for Mixed Ion and Charge Conducting Polymers.

Macromolecules that exhibit both electron transport and ionic mass transport (i.e., mixed conducting polymers) are ascendant with respect to both emerging application spaces and the elucidation of their fundamental physical principles.