Work function engineering of SnO single crystal microplates with thermal annealing

Energy Band-Modulated SnO Anodes with Improved Rate Capacity and Initial Coulombic Efficiency for Sodium-Ion Batteries

An efficient interface and composition modification strategy is proposed to significantly increase the rate capacity and initial Coulombic efficiency (ICE) of SnO anodes via energy band structure modulation for Na-ion batteries (SIBs). The as-fabricated SnO@Bi@C material with Bi nanocrystals homogeneously dispersed on and around the SnO surface is prepared by an electrospinning method. The excellently dispersed Bi nanocrystals realize an effective interface contact with SnO and Na2O, which effectively lowers the electron conduction barriers and promotes sodium-ion release and transport upon the desodiation process, increasing the rate capacity and ICE of the SnO anode. The prepared SnO@Bi@C exhibits a much higher rate capacity up to 10 A g-1, except an improved ICE of 80.67%, compared to 57.38% of SnO@C. Importantly, the intercalation of Na+ between layer-structured Bi galleries provides a good basis for excellent cycle stability due to the highways constructed inside the prepared composites. This finding provides an effective tactic to establish ion transport high-speed channels, which essentially increase the rate performance and the ICE of the SnO-based anodes.

Thin SnxNiyOz Films as p-Type Transparent Conducting Oxide and Their Application in Light-Emitting Diodes

The development of good-quality p-type transparent conducting oxides (TCOs) is essential to realize the full potential of TCOs for transparent electronics. This study investigates various optical and electrical properties of Sn_xNi_yO_z under different deposition conditions to achieve high-performance p-type TCOs. We found that a film with 20% O₂/Ar deposited at room temperature exhibits the highest p-type conductivity with a carrier concentration of 2.04 × 10¹⁷ cm^-3, a resistivity of 14.01 Ωcm, and a Hall mobility of 7.7 cm² V^-1 S^-1. We also studied the elemental properties of a Sn_xNi_yO_z film and the band alignment at the Sn_xNi_yO_z/InP interface and found reasonably large values of the conduction band offset (CBO) and valence band offset (VBO). Finally, we demonstrate stable light-emitting diodes (LEDs) with n-InP nanowires (NWs) conformably coated with a p-Sn_xNi_yO_z structure. Several films and devices were fabricated and tested over a span of 6 months, and we observed similar characteristics. This confirms the stability and reliability of the films as well as the reproducibility of the LEDs. We also investigated the temperature-dependent behavior of these LEDs and observed an additional peak due to a zinc blende/wurtzite (ZB/WZ) transition at the InP substrate and NW interface at ∼98 K and below. This study provides promising results of Sn_xNi_yO_z as a potential p-type TCO candidate for applications in electronics and optoelectronics.

Understanding Solid-Gas Reaction Mechanisms by Operando Soft X-Ray Absorption Spectroscopy at Ambient Pressure

Ambient-pressure operando soft X-ray absorption spectroscopy (soft-XAS) was applied to study the reactivity of hydroxylated SnO₂ nanoparticles toward reducing gases. H₂ was first used as a test case, showing that the gas phase and surface states can be simultaneously probed: Soft-XAS at the O K-edge gains sensitivity toward the gas phase, while at the Sn M_4,5-edges, tin surface states are explicitly probed. Results obtained by flowing hydrocarbons (CH₄ and CH₃CHCH₂) unequivocally show that these gases react with surface hydroxyl groups to produce water without producing carbon oxides and release electrons that localize on Sn to eventually form SnO. The partially reduced SnO_2 - x layer at the surface of SnO₂ is readily reoxidized to SnO₂ by treating the sample with O₂ at mild temperatures (>200 °C), revealing the nature of "electron sponge" of tin oxide. The experiments, combined with DFT calculations, allowed devising of a mechanism for dissociative hydrocarbon adsorption on SnO₂, involving direct reduction of Sn sites at the surface via cleavage of C-H bonds and the formation of methoxy- and/or methyl-tin species at the surface.

Sol–gel synthesis of large-sized polycrystalline stannous oxide and its oxidation behavior

The large-sized polycrystalline stannous oxide (SnO) synthesized by a sol–gel method was found to have attractive crystal structural properties and thermo-oxidative stability.

Enhanced charge storage properties of ultrananocrystalline diamond films by contact electrification-induced hydrogenation

We report the enhanced charge storage characteristics of ultrananocrystalline diamond (UNCD) by contact electrification-induced hydrogenation. The non-catalytic hydrogenation of UNCD films was achieved by using platinum as an electron donor and sulfuric acid as a hydrogen proton donor, confirmed by Raman spectroscopy and time-of-flight secondary ion mass spectroscopy (TOF-SIMS). Chemical treatment with only a H₂SO₄ solution is responsible for the surface oxidation. The oxidation of UNCD resulted in an increase in the quantity and duration of the tribocharges. After non-catalytic hydrogenation, the generation of friction-induced tribocharges was enhanced and remained for three hours and more. We show that the hydrogen incorporation on grain boundaries is responsible for the improvement of charge storage capability, because the doped hydrogen acts as a trap site for the tribocharges. This lab-scale and succinct method can be utilized to control charge trap capability in nanoscale memory electronics.

The enhanced charge storage characteristics of ultrananocrystalline diamond caused by contact electrification-induced hydrogenation was demonstrated by using atomic force microscopy.

Morphology modulation of SnO photocatalyst: from microplate to hierarchical architectures self-assembled with thickness controllable nanosheets

We prepared plate-like SnO and hierarchical SnO architectures with tunable morphologies and decreased size, which exhibit morphology-dependent photocatalytic properties.