In this work, we design and fabricate tunable pixelated infrared emitter arrays based on graphene transistors. We use finite element analysis to simulate a 5-by-3 pixelated emitter array, where localized heating area can be confined within a size of 25 mu m and reaches more than 10 K temperature rise within 3 mu s. By applying fast sweeping scheme with electrostatic voltage inputs, tunable surface patterns assembling dynamic alphabetical letters of microscale sizes are demonstrated and captured via thermal mapping with its thermal emission variation caused by localized temperature rise. Our results show that thermal emission can be highly localized and reconfigurable both spatially and temporally, which paves the way for developing and boosting the performance of microscale and nanoscale thermally driven devices for communication, characterization, sensing and actuation.

Active metasurfaces have recently emerged as compact, lightweight, and efficient platforms for dynamic control of electromagnetic fields and optical responses. However, the complexities associated with their post-fabrication tunability significantly hinder their widespread applications, especially for the mid-infrared range due to material scarcity and design intricacy. Here, we experimentally demonstrate highly dynamic, pixelated modulations of coherent mid-infrared emission based on an electrically programmable plasmonic metasurface integrated with graphene field-effect transistors (Gr-FETs). The ultrabroad infrared transparency of graphene allows for customized control over plasmonic meta-atoms, thus achieving coherent mid-infrared states across a broad range of wavelengths, directions, and polarizations. The spatial temperature modulation generated by Gr-FETs is effectively synergized with the emissivity control by the localized surface plasmon polaritons and quasi-bound states in the continuum from gold nanoantennas. This integrated temperature-emissivity modulation of metasurfaces is systematically extended to form a pixelated 2D array with low crosstalk, envisioning advanced approaches toward scalable 2D electrical wiring for densely packed, independently addressable pixels.

Thermal signatures carry unique infrared appearances and spectral fingerprints of objects, but controlling them across spatial, temporal, and spectral domains remains challenging due to thermal emission's slow, diffuse, and broadband emitting nature. We demonstrate a reconfigurable ultrafast thermal metamaterial pixel array integrating active metasurfaces with dual-gate graphene transistors (Gr-FETs). Each pixel's Gr-FETs provide heater-switch dual functionalities: one as a broadband transparent microheater supporting arbitrary metasurface designs for multicolor, narrowband infrared emission with ultrafast modulation speed of minimum 187 kHz, and the other as an electrical switch enabling unified array control without compromising emission intensity. Decoupling thermal generation and emission design processes, our approach provides unprecedented programming flexibility across space, time, and wavelength. Our fabricated array experimentally demonstrated 26 alphabetical letters through progressive scanning, paving the way for universal thermal signature control in advanced thermal-infrared applications.

Effective heat dissipation remains a grand challenge for energy-dense devices and systems. As heterogeneous integration becomes increasingly inevitable in electronics, thermal resistance at interfaces has emerged as a critical bottleneck for thermal management. However, existing thermal interface solutions are constrained by either high thermal resistance or poor reliability. We report a strategy to create printable, high-performance liquid-infused nanostructured composites, comprising a mechanically soft and thermally conductive double-sided Cu nanowire array scaffold infused with a customized thermal-bridge liquid that suppresses contact thermal resistance. The liquid infusion concept is versatile for a broad range of thermal interface applications. Remarkably, the liquid metal infused nanostructured composite exhibits an ultra-low thermal resistance <1 mm² K W-1 at interface, outperforming state-of-the-art thermal interface materials on chip-cooling. The high reliability of the nanostructured composites enables undegraded performance through extreme temperature cycling. We envision liquid-infused nanostructured composites as a universal thermal interface solution for cooling applications in data centers, GPU/CPU systems, solid-state lasers, and LEDs. Thermal resistance at interfaces is a critical bottleneck for the thermal management of electronic devices. Here, authors report a high-performance liquid-infused nanostructured composite with thermal resistance under 1 mm² K W−1 and reliability for advanced electronic cooling.

Active metasurfaces have recently emerged as compact, lightweight, and efficient platforms for dynamic control of electromagnetic fields and optical responses. However, the complexities associated with their post-fabrication tunability significantly hinder their widespread applications, especially for the mid-infrared range due to material scarcity and design intricacy. Here, we experimentally demonstrate highly dynamic, pixelated modulations of coherent mid-infrared emission based on an electrically programmable plasmonic metasurface integrated with graphene field effect transistors (Gr-FETs). The ultrabroad infrared transparency of graphene allows for free-form control over plasmonic meta-atoms, thus achieving coherent mid-infrared states across a broad range of wavelengths and polarizations. The spatial temperature modulation generated by Gr-FETs is effectively synergized with the emissivity control by the localized surface plasmon polaritons from gold nanoantennas. This integrated temperature-emissivity modulation of metasurfaces is systematically extended to form a pixelated 2D array, envisioning new approaches toward scalable 2D electrical wiring for densely packed, independently controlled pixels.

Despite the recent advancements of passive and active cooling solutions for electronics, interfaces between materials have generally become crucial barriers for thermal transport because of intrinsic material dissimilarity and surface roughness at interfaces. We demonstrate a 3D graphene-nanowire “sandwich” thermal interface that enables an ultralow thermal resistance of ∼0.24 mm2·K/W that is about 1 order of magnitude smaller than those of solders and several orders of magnitude lower than those of thermal greases, gels, and epoxies, as well as a low elastic and shear moduli of ∼1 MPa like polymers and foams. The flexible 3D “sandwich” exhibits excellent long-term reliability with >1000 cycles over a broad temperature range from −55 °C to 125 °C. This nanostructured thermal interface material can greatly benefit a variety of electronic systems and devices by allowing them to operate at lower temperatures or at the same temperature but with higher performance and higher power density.

Thermal interfaces are vital for effective thermal management in modern electronics, especially in the emerging fields of flexible electronics and soft robotics that impose requirements for interface materials to be soft and flexible in addition to having high thermal performance. Here, a novel sandwich-structured thermal interface material (TIM) is developed that simultaneously possesses record-low thermal resistance and high flexibility. Frequency-domain thermoreflectance (FDTR) is employed to investigate the overall thermal performance of the sandwich structure. As the core of this sandwich, a vertically aligned copper nanowire (CuNW) array preserves its high intrinsic thermal conductivity, which is further enhanced by 60% via a thick 3D graphene (3DG) coating. The thin copper layers on the top and bottom play the critical roles in protecting the nanowires during device assembly. Through the bottom-up fabrication process, excellent contacts between the graphene-coated CuNWs and the top/bottom layer are realized, leading to minimal interfacial resistance. In total, the thermal resistance of the sandwich is determined as low as ~0.23 mm2  K W-1 . This work investigates a new generation of flexible thermal interface materials with an ultralow thermal resistance, which therefore renders the great promise for advanced thermal management in a wide variety of electronics.

Transition metal nitrides (TMNs) have received special concern as important energy storage materials, owing to their high conductibility, good mechanical strength, and superior corrosion resistance. However, their insufficient capacitance and poor cycling stability limit their practical applications for supercapacitors. Here, a novel three-dimensional (3D) self-supported integrated electrode consisted of porous nanowall arrays of ultrafine cobalt nitride (Co4N) nanoparticles encapsu-lated in a lanthanum oxycyanamide (LOC) matrix on carbon cloth (Co4N@LOC/CC) for outstanding electrochemical energy storage is rationally designed and fabricated. The 3D monolithic configuration of porous nanowall arrays facilitates the mass/charge transfer, the exposure of electroactive sites, and the enhancement of electrical conductivity. Meanwhile, the unique core-shell structure of Co4N@LOC can prevent ultrafine Co4N nanoparticles from sintering, agglomeration, and oxidation and promotes electron transfer dynamics during the redox reaction, meanwhile enhancing the stability of the electrode. Additionally, the synergy of Co4N and LOC can result in an efficient electron/ion transport in the process of the charge-discharge. Because of these features, the Co4N@LOC/CC electrode displays superior specific capacitance (895.6 mF cm-2 or 613.4 F g-1 at 1 mA cm-2) and admirable cycling durability (87.9% capacitance reservation after 10 000 cycles), surpassing the majority of nitride-based electrodes reported thus far. Furthermore, after being assembled into an asymmetric supercapacitor using active carbon (AC) as an anode, the obtained Co4N@LOC/CC//AC/CC device displays a high energy density of 41.7 Wh kg-1 at the power density of 875.8 W kg-1 with a high capacitance reservation of 87.6% after 5000 cycles at 2 mA cm-2. This work offers an efficient approach of combining TMNs with rare earth compounds to enhance the capacitance and stability of TMNs for supercapacitor electrodes.

Zinc air cell (ZAC) is a promising alternative for Li-ion battery owing to its superior energy density, while it suffers from alkaline electrolyte related issues. Here, a tri-electrolyte microfluidic zinc-air cells are developed based on structural evolution and electrolyte engineering. By strategically using acidic catholyte instead of alkalis, the device performance is largely improved and stabilized, benefiting from 0.8V higher cathodic reaction potential and prohibited carbonate contamination. Since alkalis are still preferred for the anolyte, a third bridge-electrolyte is applied to avoid the neutralization of two electrolytes. To avoid using membranes, a microfluidic cell configuration is further integrated. Without the ion-restriction of the membranes, H2SO4 becomes applicable for catholyte and contributes to a stable operation with further improved potential of 2.18 V. Furthermore, the electrolyte mixing behavior is investigated from both experimental and simulation aspects, which demonstrates the recyclability of the electrolytes and provides guidance for the real application.

The aluminum-air cell is one of the most promising candidates for next-generation power sources due to its high theoretical energy density. In particular, a tri-electrolyte aluminum-air cell shows high stability and cell voltage. However, the output power density is limited because of the increased internal resistance. Here, we demonstrate a tri-electrolyte aluminum-air microfluidic cell, which takes advantages of the bridging electrolyte and the co laminar flow to separate the alkaline anolyte from the acidic catholyte. The novel cell structure helps to maintain high ion exchange efficiency, minimize the electrolyte neutralization, and improve the cell stability. The short-circuit current density and maximum power density at the first electrolyte cycle are up to 367.46 mA cm(-2) and 189.22 mW cm(-2), respectively; after 10 electrolyte cycles, the variation is less than 2.85% and 4.69%, respectively. The cell internal resistivity is 5.42, 5.41, and 5.55 & OHM; cm(2) at cycle 1 under flow rates of 0.5, 1.0 and 2.0 ml min(-1), respectively, which demonstrates the cell stability under flowing electrolytes. An integrated cell system assembled with 24 cells is further fabricated and evaluated. The short-circuit current only drops to half at cell electrolyte cycle 156 theoretically. Therefore, this work provides an alternative strategy for economical and long-lasting aluminum-air cells as less-frequent power sources.

Methanol crossover is one of the main challenges for direct methanol fuel cells (DMFCs). Depositing a metal barrier on Nafion can reduce the crossover but usually faces the metal cracking issues. This study presents a new composite membrane in which an anodic aluminum oxide (AAO) substrate is impregnated with a Nafion solution and then coated with a layer of Au. The AAO/Nafion/Au composite membrane shows an ideal metal crack-free surface. Higher and more stable voltage has been achieved for the cell with the membrane, indicating an effectively suppressed methanol-crossover. Results reveal that there is a tradeoff between suppressing the methanol crossover and increasing the ion transmission. By optimizing the membrane, it can not only suppress the methanol crossover but also enhance the output performance of DMFCs. The current density and power density of the cells can be enhanced by 59% and 52.85%, respectively, compared to the cell with a commercial Nafion 117. Overall, this work provides a new approach to designing crack-free membranes for DMFCs.

Perovskite solar cells (PSCs) commonly exhibit significant performance degradation due to ion migration through the top charge transport layer and ultimately metal electrode corrosion. Here, we demonstrate an interfacial management strategy using a boron chloride subphthalocyanine (Cl6SubPc)/fullerene electron-transport layer, which not only passivates the interfacial defects in the perovskite, but also suppresses halide diffusion as evidenced by multiple techniques, including visual element mapping by electron energy loss spectroscopy. As a result, we obtain inverted PSCs with an efficiency of 22.0% (21.3% certified), shelf life of 7000 h, T80 of 816 h under damp heat stress (compared to less than 20 h without Cl6SubPc), and initial performance retention of 98% after 2000 h at 80 °C in inert environment, 90% after 2034 h of illumination and maximum power point tracking in ambient for encapsulated devices and 95% after 1272 h outdoor testing ISOS-O-1. Our strategy and results pave a new way to move PSCs forward to their potential commercialization solidly.

Crystallized p‐type small‐molecule semiconductors have great potential as an efficient and stable hole transporting materials (HTMs) for perovskite solar cells (PSCs) due to their relatively high hole mobility, good stability, and tunable highest occupied molecular orbitals. Here, a thienoacene‐based organic semiconductor, 2,9‐diphenyldinaphtho[2,3‐ b :2′,3′‐ f ]thieno[3,2‐ b ]thiophene (DPh‐DNTT), is thermally evaporated and employed as the dopant‐free HTM that can be scaled up for large‐area fabrication. By controlling the deposition temperature, the molecular orientation is modulated into a dominant face‐on orientation with π–π stacking direction perpendicular to the substrate surface, maximizing the out‐of‐plane carrier mobility. With an engineered face‐on orientation, the DPh‐DNTT film shows an improved out‐of‐plane mobility of 3.3 × 10 −2 cm 2 V −1 s −1 , outperforming the HTMs reported so far. Such orientation‐reinforced mobility contributes to a remarkable efficiency of 20.2% for CH 3 NH 3 PbI 3 inverted PSCs with enhanced stability. The results reported here provide insights into engineering the orientation of molecules for the dopant‐free organic HTMs for PSCs.

A well-designed scaffold that allows the full exposure of nanophotocatalyst to reactants is equally important with an efficient catalyst material in realizing a high-performance photocatalytic reaction. In this work, we develop a three-dimensional (3D) bandgap tunable perovskite quantum dots (PQDs)/polyethersulfone (PES) monolithic film to maximize the specific area and enhance light harvesting, thereby making full use of PQDs in solar-driven CO2 reduction. The PQDs are electrostatically selfattached to the 3D PES scaffold with minimal agglomeration and clustering so that can be fully exposed to gaseous reactant and sustaining its superior high surface/volume ratio. Through composition engineering, the small-bandgap I-rich CsPbIxBr3-x PQDs along with the 3D PES scaffold achieve a high electron consumption rate of 64.90 mu mol g(-1) h(-1), exceeding all the reported PQD-based single photocatalysts in CO2 photoreduction. Our work provides a new platform to fully exploit the perovskite nanomaterials by constructing 3D nanocatalyst/polymer film for highly efficient photocatalytic reactions. (C) 2021 Elsevier Ltd. All rights reserved.

Current primary energy generation systems produce a significant amount of waste CO2 and low-grade heat which consequently have a significant negative impact on the global climate and environment. In contrast to current carbon capture and storage (CCS) technologies which require external input energy or mass to extract and store the waste without efficient utilization, this study proposes a thermally regenerative CO2-induced pH-gradient cell (TRCPC) that simultaneously utilizes CO2 and low-grade heat for waste-to-electricity conversion. CO2 is absorbed in one side of the symmetric electrolyte and causes a change in pH of the cell to induce voltage generation, achieving a peak power density of 0.578 Wm(-2). After discharging, the system can be regenerated using low-grade heat while the CO2 can then be stored and transported. This research proposes a promising method with economic and environmental benefits that converts CO2 and waste heat into electricity before further CO2 storage.

Aluminum/air microfluidic fuel cell (MFC) combines the advantages of co-laminar MFC and aluminum/air batteries with high energy density, low cost, membraneless and miniaturized design, which is a promising device to power the numerous nodes in the Internet of Things (IoT) ecosystems. Here, we propose a recirculating dual-electrolyte aluminum/air MFC with an alkaline anolyte and an acid catholyte. The cell exhibits an outstanding performance with an open-circuit voltage of 2.2 V and a short-current density of 1 A cm−2, benefiting from the dual-electrolyte design. In order to prevent the naturalization reaction between the electrolytes and improve the utilization rate, a regular hierarchical porous carbon paper is applied as the separator, which minimizes the mixing of electrolytes and facilitates the recirculation. This work provides an alternative route for cost-effective and high-performance aluminum/Air MFCs toward real applications.

Hybrid perovskites are emerging as a promising, high-performance luminescent material; however, the technological challenges associated with generating high-resolution, free-form perovskite structures remain unresolved, limiting innovation in optoelectronic devices. Here, we report nanoscale three-dimensional (3D) printing of colored perovskite pixels with programmed dimensions, placements, and emission characteristics. Notably, a meniscus comprising femtoliters of ink is used to guide a highly confined, out-of-plane crystallization process, which generates 3D red, green, and blue (RGB) perovskite nanopixels with ultrahigh integration density. We show that the 3D form of these nanopixels enhances their emission brightness without sacrificing their lateral resolution, thereby enabling the fabrication of high-resolution displays with improved brightness. Furthermore, 3D pixels can store and encode additional information into their vertical heights, providing multilevel security against counterfeiting. The proof-of-concept experiments demonstrate the potential of 3D printing to become a platform for the manufacture of smart, high-performance photonic devices without design restrictions.

Crystallized p-type small-molecule semiconductors have great potential as efficient and stable hole transporting materials (HTMs) for perovskite solar cells (PSCs) due to their relatively high hole mobility, good stability and tunable HOMOs depending on the molecular orientation. Here, a thienoacene-based organic semiconductor, 2,9diphenyldinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (DPh-DNTT), was thermally evaporated and employed as the dopant-free HTM that can be scaled up for large-area fabrication. By controlling the deposition temperature, the molecular orientation was modulated into a dominated face-on orientation possessing π-π stacking direction 2 towards the surface normal to maximize the out-of-plane carrier mobility. With an engineered face-on orientation, the DPh-DNTT film shows an improved out-of-plane mobility of 3.3 ×10 cmVs, outperforming the HTMs reported so far. Such orientation-reinforced mobility contributes to a remarkable efficiency of 20.2% for CH3NH3PbI3 inverted PSCs with enhanced stability. The results reported here provide insights into engineering the orientation of molecules for the dopant-free organic HTMs for PSCs.