Search

Excellent silicon surface passivation is achieved by atomic layer deposition (ALD) grown hafnium oxide (HfOx) films on silicon surfaces (both n-type and p-type). It is inferred from the study that the silicon surface passivation by HfOx thin films is a film-thickness-dependent quality and a minimum film thickness of ∼2 nm is essential to passivate the silicon surface. A good level of surface passivation (surface recombination velocity, SRV< 20 cm/s) can be achieved for film thickness, d >5 nm. However, the best results are obtained for hydrogen-annealed, ∼8.5-nm-thin HfOx films. SRV as low as 3.5 cm/s (effective minority carrier lifetime, τeff ∼5 ms) and 4.4 cm/s (τeff ∼4 ms) are realized on p-type and n-type silicon surfaces, respectively. The injection level dependence of τeff reveals that HfOx films provide better passivation for n-type silicon compared to p-type silicon at low injection levels. Hydrogen present in the annealing ambient first saturates the dangling bonds at the film/silicon interface and then affects the oxide charge density. Effective oxide charge density is positive in HfOx/n-Si samples and negative in HfOx/p-Si samples. This creates an accumulation condition near the silicon surface for both substrate-type situations and is responsible for effective passivation in both types of substrates. Thus, our study demonstrates that ALD-grown HfOx films offer excellent passivation for silicon surfaces.

In this work, nanocrystalline BaFe2O4(BFO) has been green synthesized and demonstrated various nanostructures of BFO as an anode material for electrochemical energy storage applications. Annealing temperature significantly influenced the physical, optical and electrochemical properties of nanocrystalline BFO. The HR-XRD pattern shows the formation of an orthorhombic spinel-like phase and Bb21m(36) space group of BFO. The crystallite size increases with increasing annealing temperature and is attributed to the Ostwald effect. Different nanostructures such as quasi-spherical, hexagonal flakes and nano-rods of BFO were observed. The EDX spectra and XPS analysis shows that the material consists Ba, Fe and O elements in Ba2+, Fe2+, Fe3+and O2−oxidation states respectively. FTIR spectroscopy spectra have the metal-oxide peaks (BaO and FeO) in the fingerprint region which shows the successful formation of BFO. The estimated optical bandgap of BFO using the Kubelka-Munk function from DRS spectra decreases with increasing temperature. The BET analysis shows the mesoporous nature and the highest surface area of BFO-800 is 36.83 m2/g among all the samples. The high surface area provides a greater number of active sites for the electrochemical reactions to occur. Thus, the BFO sample annealed at 800 °C showed the highest specific capacitance of 1098 F/g at 1 A/g current density, power density and energy density are 1.99 kW/kg and 38.12 Wh/kg respectively. Additionally, the BFO electrode displayed long term cyclic stability retention of 80.27 % over 3000 GCD cycles. Thus, cost-effective green synthesized BFO nanocrystals are potential candidates for energy storage applications.

Introduction and Aims:Therapy of primary membranous nephropathy (PMN) with progressive advanced kidney dysfunction is challenging with limited literature and no clear therapeutic strategies. This is due to the scant evidence of effectiveness and uncertainty around the risk-benefit profile of immunosuppression (ImS) when eGFR is less than 30 mL/min. We aimed to determine long-term clinical outcomes in patients with PMN and severe renal impairment treated with combined cyclophosphamide and steroids. Methods:The study is a single-center retrospective longitudinal cohort study. All patients (between 2004 and 2019) with biopsy confirmed PMN who initiated combination therapy with steroids and cyclophosphamide and had an eGFR of ≤30 mL/min/1.73 m2 at the time of initiation of therapy were included for analysis. Clinical and laboratory parameters including anti-PLA2R-Ab were monitored as per standard clinical guidance. Primary outcome was achievement of partial remission. Secondary outcomes included immunological remission, need for renal replacement therapy, and adverse effects. Results:Eighteen patients with median age of 68 (IQR 58–73) years and 5:1 M:F ratio received the combination therapy when eGFR was ≤30 mL/min/1.73 m2 (CKD-EPI). At time of ImS, median eGFR and uPCR were 23 (IQR 18–27) mL/min/1.73 m2 and 8.4 (IQR 6.9–10.7) g/g, respectively. Median follow-up was for 67 (IQR 27–80) months. 16 patients (89%) achieved partial remission and 7 (39%) achieved complete remission. eGFR increased by 7 mL/min/1.73 m2 (27%) after 1 year of starting ImS treatment and 12 mL/min/1.73 m2 at end of follow-up. Two patients (11%) developed end-stage renal disease needing renal replacement therapy. 67% achieved both immunological and clinical remission. At the end of the follow-up period, 2 (11%) patients required hospitalization secondary to infections, 4 (22%) patients developed cancer and 4 patients died (22%). Conclusion:Combination therapy with cyclophosphamide and steroids is effective in achieving partial remission and improving renal function in PMN with advanced renal dysfunction. Prospective controlled studies are required to provide further evidence to rationalize treatment and improve outcomes in such patients.

Samarium (Sm)-doped Ca12Al14O33(CAO) phosphors were synthesized using solid-state reaction method. Crystal structure of Sm3+-doped CAO was investigated using X-ray diffraction and Raman spectroscopy analysis. Raman active peaks at 320 cm−1, 512 cm−1and 754 cm−1and 773 cm−1were attributed to Ca–O, vibration between Al–O–Al, and ν3 mode of AlO45−groups, respectively. The optical band-gap for pure and Sm3+ion-doped CAO was calculated to be 4.55 eV and 4.50 eV, respectively. Field emission scanning electron microscope (FESEM) image of synthesized phosphors exhibited agglomerated coin-like structure spread with voids. Luminescence properties were analyzed by photoluminescence (PL) spectra. The emission of reddish-orange light due to transition of 4G5/2- 6H7/2was observed, which was confirmed by the Commission Internationale de l’Eclairage (CIE) chromatic coordinate graph. The maximum intensity of orange-red light was observed in 0.5% Sm3+-doped CAO, and the calculated color purity was 95.2%.

A Rh(III)-catalyzed regioselective redox-neutral cascade process of carbenoid functionalization followed by dephosphonylative annulation of benzoic acids with α-diazo-β-keto phosphonate has been realized, which led to the direct synthesis of a privileged 3-substituted isocoumarin scaffold. To the best of our knowledge, this is the first report of a complete redox neutral method to synthesize isocoumarins using C–H functionalization strategy. In the catalytic cycle of this reaction, there are two possible pathways for the C–C coupling between ortho-positioned carbon atom of benzoic acid and the diazo carbon atom: (i) concerted 1,2-aryl shift and (ii) stepwise metal–carbene formation followed by migratory insertion. DFT study has predicted that the concerted pathway has lower activation energy as compared to the stepwise pathway by 1.5 kcal/mol.