All-Cold Evaporation under One Sun with Zero Energy Loss by Using a Heatsink Inspired Solar Evaporator

Interfacial solar steam generation is a highly efficient and sustainable technology for clean water production and wastewater treatment. Although great progress has been achieved in improving evaporation rate and energy efficiency, it's still challenging to fully eliminate the energy loss to the surrounding environment during solar steam generation. To achieve this, a novel heatsink-like evaporator (HSE) is developed herein. During solar evaporation, the temperature on the top solar evaporation surface can be regulated by the fin structures of the HSE. For the evaporators with 5 to 7 heatsink fins, the temperature of the solar evaporation surface is decreased to be lower than the ambient temperature, which fully eliminates the radiation, convection, and conduction heat losses, leading to the absolute cold evaporation over the entire evaporator under 1.0 sun irradiation. As a result, massive energy (4.26 W), which is over 170% of the received light energy, is harvested from the environment due to the temperature deficit, significantly enhancing the energy efficiency of solar steam generation. An extremely high evaporation rate of 4.10 kg m-2 h-1 is realized with a 6-fin photothermal HSE, corresponding to an energy conversion efficiency far beyond the theoretical limit, assuming 100% light-to-vapor energy conversion.

Hierarchically Structured Porous Piezoelectric Polymer Nanofibers for Energy Harvesting

Hierarchically porous piezoelectric polymer nanofibers are prepared through precise control over the thermodynamics and kinetics of liquid-liquid phase separation of nonsolvent (water) in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) solution. Hierarchy is achieved by fabricating fibers with pores only on the surface of the fiber, or pores only inside the fiber with a closed surface, or pores that are homogeneously distributed in both the volume and surface of the nanofiber. For the fabrication of hierarchically porous nanofibers, guidelines are formulated. A detailed experimental and simulation study of the influence of different porosities on the electrical output of piezoelectric nanogenerators is presented. It is shown that bulk porosity significantly increases the power output of the comprising nanogenerator, whereas surface porosity deteriorates electrical performance. Finite element method simulations attribute the better performance to increased volumetric strain in bulk porous nanofibers.

"Two Birds with One Stone" Ruthenium(II) Complex Probe for Biothiols Discrimination and Detection In Vitro and In Vivo

In this work, a "two birds with one stone" ruthenium(II) complex probe, Ru-NBD, is proposed as an effective tool for biothiols detection and discrimination in vitro and in vivo. Ru-NBD is nonluminescent due to the quenching of Ru(II) complex emission by photoinduced electron transfer (PET) from Ru(II) center to NBD and the quenching of NBD emission through 4-substitution with "O" ether bond. Ru-NBD is capable of reacting with Cys/Hcy to form long-lived red-emitting Ru-OH and short-lived green-emitting NBD-NR, while reacting with GSH to produce Ru-OH and nonemissive NBD-SR. The long lifetime emission of Ru(II) complex allows elimination of short lifetime background and NBD-NR fluorescence for total biothiols detection ("bird" one) by time-gated luminescence (TGL) analysis, and the remarkable difference in luminescence color response allows discrimination GSH and Cys/Hcy ("bird" two) through steady-state luminescence analysis. Ru-NBD features high sensitivity and selectivity, rapid luminescence response, and low cytotoxicity, which enables it to be used as the probe for luminescence and background-free TGL detection and visualization of biothiols in live cells, zebrafish, and mice. The successful development of this probe is anticipated to contribute to the future biological studies of biothiols roles in various diseases.

Controlled Design of a Robust Hierarchically Porous and Hollow Carbon Fiber Textile for High-Performance Freestanding Electrodes

For most carbon-based materials, hierarchical porous structure including well-defined macropores, mesopores, and micropores is commonly seen in 3D aerogels, monoliths, or some carbothermic natural biomass. However, because of the filiform character and long draw ratio, it is difficult to achieve such pore network as well as attain excellent mechanical performance in a 1D single carbon fiber system. To address this issue, an innovative hierarchical porous and hollow carbon textile (HPHCT) is developed via the "dynamic template (KOH, SiO2, and Al2O3) calcination" strategy. Unlike conventional one-step activated carbonized fiber simply with meso or micropores, the fabricated textile generates honeycomb-like macropores uniformly spreading on fiber surface. More importantly, the ultra-lightweight yet flexible HPHCT is mechanically robust, superior to ordinary carbonized one. In addition, it delivers high capacitance of maximum 220 F g-1 as well as keeping long term stability with 100% retention after 10 000 cycles as freestanding electrodes in supercapacitor. Meanwhile, the all-solid integrated symmetric HPHCT supercapacitors demonstrates its high potential in powering electronics for wearable energy storage application.