A new optical touchless positioning interface based on ultrasensitive humidity responsive 1D photonic crystals utilizing the giant moisture dependent swelling capacity of 2D phosphatoantimonate nanosheets is presented. The spatially confined, full spectral color change combined with reversible transparency switching induced by the humidity sheath of a human finger allows for real time, true color lateral finger motion tracking under touchless conditions.

We report on the facile solid-state synthesis and characterization of Li7SiPS8, a new member of the tetragonal Li10GeP2S12 (LGPS)-type family of ultrafast Li+ solid electrolytes. We analyze the structure, phase stability, and Li+ conductivity of tetragonal and orthorhombic LSiPS by pulsed field gradient NMR and impedance spectroscopy, which show conductivities at room temperature of up to 2 mS cm–1. Although ranking tetragonal LiSiPS as an ultrafast solid electrolyte, the observed conductivity is unexpectedly low compared to other members of this solid-solution system. Utilizing solid-state NMR, quantitative phase analysis, and impedance spectroscopy, we identify an amorphous thiophosphate side phase with low Si content, which limits the intergrain conductivity and, hence, a potentially higher total conductivity. This case study thus highlights the need for comprehensive structural analysis of LGPS-type materials beyond the crystalline fractions to fully characterize the structure–property relationships in these glass-ceramic compounds.

The rational design of hydrogen evolution reaction (HER) electrocatalysts which are competitive with platinum is an outstanding challenge to make power-to-gas technologies economically viable. Here, we introduce the delafossites PdCrO 2 , PdCoO 2 and PtCoO 2 as a new family of electrocatalysts for the HER in acidic media. We show that in PdCoO 2 the inherently strained Pd metal sublattice acts as a pseudomorphic template for the growth of a strained (by +2.3%) Pd rich capping layer under reductive conditions. The surface modification continuously improves the electrocatalytic activity by simultaneously increasing the exchange current density j 0 from 2 to 5 mA/cm² geo and by reducing the Tafel slope down to 38 mV/decade, leading to overpotentials 10 < 15 mV for 10 mA/cm² geo , superior to bulk platinum. The greatly improved activity is attributed to the in-situ stabilization of a β-palladium hydride phase with drastically enhanced surface catalytic properties with respect to pure or nanostructured palladium. These findings illustrate how operando induced electrodissolution can be used as a top-down design concept for rational surface and property engineering through the strainstabilized formation of catalytically active phases.

P 2 S 6 were prepared and structurally characterized using single-crystal X-ray diffraction. Na 2 P 2 S 6 crystallizes in the monoclinic space group P2 1 /m (no. 11) with a = 6.6752(3) Å, b = 7.7968(4) Å, c = 9.0379(4) Å, and β = 90.151(1)°i n a new structure type that can be described as a distorted Tl 2 P 2 S 6 structure.The monoclinic structure of Na 4 P 2 S 6 [space group C2/m, no.

Thiophosphate compounds have been studied extensively in the past for their rich structural variations and for a large variety of interesting properties. Here, we report 11 new phases with the composition ALnPS (A = Na, K, Rb, Cs; Ln = lanthanide). These new thiophosphates crystallize in four different structure types, with the space groups Fdd2, P1̅, P2, and P2/c, respectively. All phases are insulating and the calculated band gaps range between 3 eV and 3.5 eV. Magnetic measurements on the compounds with open f-shells show paramagnetic behavior and magnetic moments that match the expected free ion values of the respective lanthanide cations. We present a structural stability phase diagram for the ALnPS family of compounds, which reveals a clear relationship between ionic radii and the preferred crystal structure, as well as stability regions to form ALnPS-type phases.