FORMATION AND PROPERTIES 0F POROUS SILICON LAYER ON HEAVILY DOPED n-Si

The anodic voltammetric curves of heavily doped n-Si in HF solution, on which three different regions have emerged, and were plotted, A porous silicon layer with fine morphology was formed in linear region.

A robust fluorine-containing ceramic cathode for direct CO_(2) electrolysis in solid oxide electrolysis cells

Stro ntium-doped lanthanum ferrite(LSF)is a potential ceramic cathode for direct CO_(2) electrolysis in solid oxide electrolysis cells(SOECs),but its application is limited by insufficient catalytic activity and stability in CO_(2)-containing atmospheres.Herein,a novel strategy is proposed to enhance the electrolytic performance as well as chemical stability,achieved by doping F into the O-site of the perovskite LSF.Doping F does not change the phase structure but reduces the cell volume and improves the chemical stability in a CO_(2)-rich atmosphere.Importantly,F doping favors oxygen vacancy formation,increases oxygen vacancy concentration,and enhances the CO_(2) adsorption capability.Meanwhile,doping with F greatly improves the kinetics of the CO_(2) reduction reaction.For example,kchem increases by 78%from3.49×10^(-4) cm s^(-1) to 6.24×10^(-4) cm s^(-1),and Dchem doubles from 4.68×10^(-5) cm^(2) s^(-1) to 9.45×10^(-5)cm^(2) s^(-1).Consequently,doping F significantly increases the electrochemical performance,such as reducing R_(p) by 52.2%from 0.226Ωcm^(2) to 0.108Ωcm^(2) at 800℃.As a result,the single cell with the Fcontaining cathode exhibits an extremely high current density of 2.58 A cm^(-2) at 800℃and 1.5 V,as well as excellent durability over 200 h for direct CO_(2) electrolysis in SOECs.

F4-TCNQ concentration dependence of the current voltage characteristics in the Au/P3HT:PCBM:F4-TCNQ/n-Si(MPS) Schottky barrier diode

In this study, we investigate some main electrical parameters of the gold/poly（3-hexylthiophene）：[6,6]-phenyl C61 bu- tyric acid methyl ester：2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane/n-type silicon （Au/P3HT：PCBM：F4-TCNQ/n- Si） metal-polymer-semiconductor （MPS） Schottky barrier diode （SBD） in terms of the effects of F4-TCNQ concentration （0%, 1%, and 2%）. F4-TCNQ-doped P3HT：PCBM is fabricated to figure out the p-type doping effect on the device per- formance. The main electrical parameters, such as ideality factor （n）, barrier height （ФB0）, series resistance （Rs）, shunt resistance （Rsh）, and density of interface states （Nss） are determined from the forward and reverse bias current-voltage （l-V） characteristics in the dark and at room temperature. The values of n, Rs, ФB0, and Nss are significantly reduced by using the 1% F4-TCNQ doping in P3HT：PCBM：F4-TCNQ organic blend layer, additionally, the carrier mobility and current are increased by the soft （1%） doping. The most ideal values of electrical parameters are obtained for 1% F4-TCNQ used diode. On the other hand, the carrier mobility and current for the hard doping （2%） become far away from the ideal diode values due to the unbalanced generation of holes/electrons and doping-induced disproportion when compared with 1% F4-TCNQ doping. These results show that the electrical properties of MPS SBDs strongly depend on the F4-TCNQ doping and doping concentration of interfacial P3HT：PCBM：F4-TCNQ organic layer. Moreover, the soft F4-TCNQ dop- ing concentration （1%） in P3HT：PCBM：F4-TCNQ organic layer significantly improves the electrical characteristics of the Au/P3HT：PCBM：F4-TCNQ/n-Si （MPS） SBDs which enables the fabricating of high-quality electronic and optoelectronic devices.

Investigation of the growth and optical properties of a Co^2＋-doped Na5Lu9F(32) single crystal

A 0.1 mol.% CoF2-doped Na5Lu9F（32）single crystal with high quality in the size of -φ10 mm×100 mm was grown by the Bridgman method. Three peaks located at 504, 544, and 688 nm and a broad band in the range of 1200–1600 nm centered at 1472 nm were observed in the absorption spectra. The absorption peak position suggests cobalt ions in the divalent state in the grown crystal. Moreover, the cobalt ions are confirmed to locate in the distorted cubic crystal structure. Upon excitation of 500 nm light, a sharp emission peak at 747 nm ascribed to the ^2T2（H1） →^4A2（F） transition was observed for the crystal. The Co^2＋-doped Na5Lu9F（32）crystal shows a potentially promising material for the application of a passively Q-switched laser operating in the near-infrared range.

Surface reconstruction,doping and vacancy engineering to improve the overall water splitting of CoP nanoarrays

Development of a general regulatory strategy for efficient overall water splitting remains a challenging task.Herein,a simple,costfairness,and general fluorination strategy is developed to realize surface reconstruction,heteroatom doping,and vacancies engineering over cobalt phosphide(CoP)for acquiring high-performance bifunctional electrocatalysts.Specifically,the surface of CoP nanoarrays(NAs)becomes rougher,meanwhile F doped into CoP lattice and creating amounts of P vacancies by fluorination,which caused the increase of active sites and regulation of charge distribution,resulting the excellent electrocatalyst performance of F-CoP NAs/copper foam(CF).The optimized F-CoP NAs/CF delivers a lower overpotential of only 35 mV at 10 mA·cm^(−2)for hydrogen evolution reaction(HER)and 231 mV at 50 mA·cm^(−2)for oxygen evolution reaction(OER),and the corresponding overall water splitting requires only 1.48 V cell voltage at 10 mA·cm^(−2),which are superior to the most state-of-theart reported electrocatalysts.This work provides an innovative and feasible strategy to construct efficient electrocatalysts.

Fluorine-induced dual defects in NiP_(2) anode with robust sodium storage performance

Metal phosphides have shown great application potential as anode for sodium-ion batteries(NIBs)owing to high theoretical capacity,suitable operation voltage and abundant resource.Unfortunately,the application of NiP_(2) anode is severely impeded by low practical capacity and fast capacity decay due to the huge volume variation and low reactivity of internal phosphorus(P)component towards Na^(+).Herein,electronic structure modulation of NiP_(2) via heteroatoms doping and introducing vacancies defects to enhance Na+adsorption sites and diffusion kinetics is successfully attempted.The as-synthesized three-dimensional(3D)bicontinuous carbon matrix decorated with well-dispersed fluorine(F)-doped NiP_(2) nanoparticles(F-NiP_(2)@carbon nanosheets)delivers a high reversible capacity(585 mAh·g^(−1) at 0.1 A·g^(−1))and excellent long cycling stability(244 mAh·g^(−1) over 1,000 cycles at 2 A·g^(−1))when tested as anode in NIBs.Density functional theory(DFT)calculations reveal that F doping in NiP_(2) induces the formation of P vacancies with increased Na+adsorption energy and accelerates the alloying of internal P component.The F-NiP_(2)@carbon nanosheets//Na_(3)V_(2)(PO_(4))_(3) full cell is evaluated showing stable long cycling life.The heteroatoms doping-induced dual defects strategy opens up a new way of metal phosphides for sodium storage.