Unassisted overall water splitting with a solar-to-hydrogen efficiency of over 10% by coupled lead halide perovskite photoelectrodes

Hydrogen is a promising future sustainable fuel candidate with boundless opportunities.Research into photoelectrochemical(PEC)water splitting based on a lead halide perovskite(LHP)has progressed significantly with the aim of more efficient solar hydrogen production.Herein,we unite a well-known photo-absorbing LHP with cost-effective water-splitting catalysts,and we introduce two types of monolithic LHP-based PEC devices that act as a photocathode and a photoanode for the hydrogen evolution reaction and oxygen evolution reaction,leading to efficient unbiased overall water splitting.Through the integration of these two monolithic LHP-based photoelectrodes,an unbiased solar-to-hydrogen conversion efficiency of 10.64%and a photocurrent density of 8.65 mA cm^(−2) are achieved.

Recent advances in lithographic fabrication of micro-/nanostructured polydimethylsiloxanes and their soft electronic applications

The intensive development of micro-/nanotechnologies offers a new route to construct sophisticated architectures of emerging soft electronics.Among the many classes of stretchable materials,micro-/nanostructured poly(dimethylsiloxane)(PDMS)has emerged as a vital building block based on its merits of flexibility,stretchability,simple processing,and,more importantly,high degrees of freedom of incorporation with other functional materials,including metals and semiconductors.The artificially designed geometries play important roles in achieving the desired mechanical and electrical performances of devices and thus show great potential for applications in the fields of stretchable displays,sensors and actuators as well as in health-monitoring device platforms.Meanwhile,novel lithographic methods to produce stretchable platforms with superb reliability have recently attracted research interest.The aim of this review is to comprehensively summarize the progress regarding micro-/nanostructured PDMS and their promising soft electronic applications.This review is concluded with a brief outlook and further research directions.

揭示银关联缺陷的双重作用:环保型AgIn0.5Ga0.5S2中发光和载流子动力学的操纵者

AgIn_(0.5)Ga_(0.5)S_(2)由于环境友好、合成成本低、成分灵活可调等优点在许多领域受到广泛关注.适当的直接带隙、无禁戒跃迁和高激子结合能使其成为一种有前途的发光材料.多组分体系的演化丰富了光电特性,并使其本征缺陷更加复杂.反过来,这些缺陷对光电性能有重要影响,从而影响其发光性能.然而,对于这类半导体,在实验中观察到的与发光相对应的点缺陷的微观机制大多是未知的或间接推断的.本工作系统地揭示了AgIn_(0.5)Ga_(0.5)S_(2)的微观缺陷与发光之间的机制.热力学稳定性表明AgIn_(0.5)Ga_(0.5)S_(2)是亚稳态的并且与次生相之间存在显著的竞争.此外,计算的缺陷结果表明,与银关联的缺陷是幕后操纵者.两个浅能级缺陷(VAg和Agi)充当载流子提供者,而四个深能级反位缺陷(AgIn,AgGa,InAg和GaAg)充当载流子湮灭者.最后,载流子动力学的研究揭示了四种深能级反位缺陷对载流子辐射过程的不利影响.这些旨在为AgIn_(0.5)Ga_(0.5)S_(2)在发光领域的功能应用提供重要指导.

Transferable,highly crystalline covellite membrane for multifunctional thermoelectric systems

Emerging freestanding membrane technologies,especially using inorganic thermoelectric materials,demonstrate the potential for advanced thermoelectric platforms.However,using rare and toxic elements during material processing must be circumvented.Herein,we present a scalable method for synthesizing highly crystalline CuS membranes for thermoelectric applications.By sulfurizing crystalline Cu,we produce a highly percolated and easily transferable network of submicron CuS rods.The CuS membrane effectively separates thermal and electrical properties to achieve a power factor of 0.50 mW m^(-1) K^(-2) and thermal conductivity of 0.37 W m^(-1) K^(-1) at 650 K(estimated value).This yields a record-high dimensionless figure-of-merit of 0.91 at 650 K(estimated value)for covellite.Moreover,integrating 12 CuS devices into a module resulted in a power generation of4μW atΔT of 40 K despite using a straightforward configuration with only p-type CuS.Furthermore,based on the temperature-dependent electrical characteristics of CuS,we develop a wearable temperature sensor with antibacterial properties.

Highly ordered inkjet-printed quantum-dot thin films enable efficient and stable QLEDs with EQE exceeding 23%

Inkjet-printed quantum dot light-emitting diodes(QLEDs)are emerging as a promising technology for next-generation displays.However,the progress in fabricating QLEDs using inkjet printing technique has been slower compared to spin-coated devices,particularly in terms of efficiency and stability.The key to achieving high performance QLEDs lies in creating a highly ordered and uniform inkjet-printed quantum dot(QD)thin film.In this study,we present a highly effective strategy to significantly improve the quality of inkjet-printed CdZnSe/CdZnS/ZnS QD thin films through a pressure-assisted thermal annealing(PTA)approach.Benefiting from this PTA process,a high quality QD thin film with ordered packing,low surface roughness,high photoluminescence and excellent electrical property is obtained.The mechanism behind the PTA process and its profound impact on device performance have been thoroughly investigated and understood.Consequently,a record high external quantum efficiency(EQE)of 23.08%with an impressive operational lifetime(T50)of up to 343,342h@100cdm−2,and a record EQE of 22.43%with T50 exceeding to 1,500,463h@100cdm−2 are achieved in inkjet-printed red and green CdZnSe-based QLEDs,respectively.This work highlights the PTA process as an important approach to realize highly efficient and stable inkjet-printed QLEDs,thus advancing QLED technology to practical applications.

Wireless,multimodal sensors for continuous measurement of pressure,temperature,and hydration of patients in wheelchair

Individuals who are unable to walk independently spend most of the day in a wheelchair.This population is at high risk for developing pressure injuries caused by sitting.However,early diagnosis and prevention of these injuries still remain challenging.Herein,we introduce battery-free,wireless,multimodal sensors and a movable system for continuous measurement of pressure,temperature,and hydration at skin interfaces.The device design includes a crack-activated pressure sensor with nanoscale encapsulations for enhanced sensitivity,a temperature sensor for measuring skin temperature,and a galvanic skin response sensor for measuring skin hydration levels.The movable system enables power harvesting,and data communication to multiple wireless devices mounted at skin-cushion interfaces of wheelchair users over full body coverage.Experimental evaluations and numerical simulations of the devices,together with clinical trials for wheelchair patients,demonstrate the feasibility and stability of the sensor system for preventing pressure injuries caused by sitting.

Multi-redox phenazine/non-oxidized graphene/cellulose nanohybrids as ultrathick cathodes for high-energy organic batteries

Various redox-active organic molecules can serve as ideal electrode materials to realize sustainable energy storage systems. Yet, to be more appropriate for practical use, considerable architectural engineering of an ultrathick, high-loaded organic electrode with reliable electrochemical performance is of crucial importance. Here, by utilizing the synergetic effect of the non-covalent functionalization of highly conductive non-oxidized graphene flakes (NOGFs) and introduction of mechanically robust cellulose nanofiber (CNF)-intermingled structure, a very thick (≈ 1 mm), freestanding organic nanohybrid electrode which ensures the superiority in cycle stability and areal capacity is reported. The well-developed ion/electron pathways throughout the entire thickness and the enhanced kinetics of electrochemical reactions in the ultrathick 5,10-dihydro-5,10-dimethylphenazine/NOGF/CNF (DMPZ-NC) cathodes lead to the high areal energy of 9.4 mWh·cm−2 (= 864 Wh·kg−1 at 158 W·kg−1). This novel ultrathick electrode architecture provides a general platform for the development of the high-performance organic battery electrodes.

Fundamental principles and development of proximity-field nanopatterning toward advanced 3D nanofabrication

Three-dimensional(3D)nanoarchitectures have offered unprecedented material performances in diverse applications like energy storages,catalysts,electronic,mechanical,and photonic devices.These outstanding performances are attributed to unusual material properties at the nanoscale,enormous surface areas,a geometrical uniqueness,and comparable feature sizes with optical wavelengths.For the practical use of the unusual nanoscale properties,there have been developments for macroscale fabrications of the 3D nanoarchitectures with process areas over centimeter scales.Among the many fabrication methods for 3D structures at the nanoscale,proximity-field nanopatterning(PnP)is one of the promising techniques that generates 3D optical holographic images and transforms them into material structures through a lithographic process.Using conformal and transparent phase masks as a key factor,the PnP process has advantages in terms of stability,uniformity,and reproducibility for 3D nanostructures with periods from 300 nm to several micrometers.Other merits of realizing precise 3D features with sub-100 nm and rapid processes are attributed to the interference of coherent light diffracted by phase masks.In this review,to report the overall progress of PnP from 2003,we present a comprehensive understanding of PnP,including its brief history,the fundamental principles,symmetry control of 3D nanoarchitectures,material issues for the phase masks,and the process area expansion to the wafer-scale for the target applications.Finally,technical challenges and prospects are discussed for further development and practical applications of the PnP technique.

Growth of Serpentine Carbon Nanotubes on Quartz Substrates and Their Electrical Properties

A simple method for high-yield,chemical vapor deposition(CVD)synthesis of serpentine carbon nanotubes,employing quartz substrates and a molecular cluster catalyst,is described.The growth mechanism is analyzed by controlled addition of nanoscale barriers,and by mechanical analysis of the curved sections.The serpentine structures are used to study the electrical transport properties of parallel arrays of identical nanotubes,which show three-terminal conductance that scales linearly with the number of nanotube segments.