Dhanasekaran Vikraman

Evaluation of the physical, optical, and electrical properties of SnO2: F thin films prepared by nebulized spray pyrolysis for optoelectronics

Fluorine-doped tin oxide (SnO2:F, FTO) thin films were prepared by the nebulized spray pyrolysis technique on glass substrates using tin(IV) chloride pentahydrate (SnCl2·5H2O) and ammonium fluoride (NH4F) as source materials. Different volumes of solvent were used to prepare the spray solution, and their effects on structural, optical, morphological, and electrical properties were investigated. X-ray diffraction patterns revealed the polycrystalline tetragonal structure of FTO films. FESEM images demonstrated well-aligned trigonal-shaped nano-grains. Optical band gap values were estimated to be in the range of 3.71–3.66xa0eV by Tauc’s plot. The effects of solvent volume on the resistivity, conductivity, carrier concentration, mobility, and figure of merit of FTO films were examined. The lowest electrical resistivity and sheet resistance values were 1.90u2009×u200910−4xa0Ωxa0cm and 4.96xa0Ω/cm, respectively.

An enhanced electrochemical and cycling properties of novel boronic Ionic liquid based ternary gel polymer electrolytes for rechargeable Li/LiCoO 2 cells

A new generation of boronic ionic liquid namely 1-ethyl-3-methylimidazolium difluoro(oxalate)borate (EMImDFOB) was synthesized by metathesis reaction between 1-ethyl-3-methylimiazolium bromide and lithium difluoro(oxalate)borate (LiDFOB). Ternary gel polymer electrolyte membranes were prepared using electrolyte mixture EMImDFOB/LiDFOB with poly vinylidenefluoride-co-hexafluoropropylene (PVdF-co-HFP) as a host matrix by facile solvent-casting method and plausibly demonstrated its feasibility to use in lithium ion batteries. Amongst ternary gel electrolyte membrane, DFOB-GPE3, which contained 80u2009wt% of EMImDFOB/LiDFOB and 20u2009wt% PVdF-co-HFP, showed excellent electrochemical and cycling behaviors. The highest ionic conductivity was found to be 10−3 Scm−1 at 378u2009K. Charge-discharge profile of Li/DFOB-GPE3/LiCoO2 coin cell displayed a maximum discharge capacity of 148.4 mAhg−1 at C/10 rate with impressive capacity retention capability and columbic efficiency at 298u2009K.

Large area growth of MoTe 2 films as high performance counter electrodes for dye-sensitized solar cells

A cost effective and efficient alternative counter electrode (CE) to replace commercially existing platinum (Pt)-based CEs for dye-sensitized solar cells (DSSCs) is necessary to make DSSCs competitive. Herein, we report the large-area growth of molybdenum telluride (MoTe2) thin films by sputtering-chemical vapor deposition (CVD) on conductive glass substrates for Pt-free CEs of DSSCs. Cyclic voltammetry (CV), Tafel curve analysis, and electrochemical impedance spectroscopy (EIS) results showed that the as-synthesized MoTe2 exhibited good electrocatalytic properties and a low charge transfer resistance at the electrolyte-electrode interface. The optimized MoTe2 CE revealed a high power conversion efficiency of 7.25% under a simulated solar illumination of 100u2009mWu2009cm−2 (AM 1.5), which was comparable to the 8.15% observed for a DSSC with a Pt CE. The low cost and good electrocatalytic properties of MoTe2 thin films make them as an alternative CE for DSSCs.

In vitro cytotoxicity activity of novel Schiff base ligand–lanthanide complexes

A Schiff base ligand (SBL), N2, N3-bis (anthracen-9-ylmethylene) pyridine-2, 3-diamine, was synthesized through the condensation of 2,6-diaminopyridine and anthracene-9-carbaldehyde using a 1:2 ratio. 1H NMR spectra confirmed the observation of non-involvement aromatic carboxylic proton in SBL. A novel series of lanthanide (i.e., praseodymium (Pr), erbium (Er), and ytterbium (Yb))-based SBL metal complexes was successfully synthesized, and their functional groups were elaborately demonstrated using UV–visible, Fourier transform infrared (FT-IR), and fluorescence spectroscopy analyses. FT-IR spectral studies revealed that SBL behaved as a bidentate ligand and it was structured with metal ions by the two azomethine nitrogens. The synthesized SBL-based metal complexes were elaborately performed for cytotoxicity activity versus Vero, human breast cancer (MCF7), and cervical (HeLa) anticancer cell lines.

Synthesis of MoS2(1−x)Se2x and WS2(1−x)Se2x alloys for enhanced hydrogen evolution reaction performance

Herein, we demonstrate the synthesis of molybdenum disulphoselenide (MoS2(1−x)Se2x) and tungsten disulphoselenide (WS2(1−x)Se2x) alloys onto FTO substrates, to obtain a higher hydrogen evolution reaction (HER) activity compared to pristine MoS2 and WS2. By incorporating selenium (Se) into MoS2 and WS2 matrices, an excellent HER catalytic activity was ensured in an acidic electrolyte with overpotentials of 141 mV and 167 mV @ 10 mA cm−2 with Tafel slopes of 67 and 107 mV per decade for MoS2(1−x)Se2x and WS2(1−x)Se2x, respectively. Moreover, MoS2(1−x)Se2x and WS2(1−x)Se2x alloys showed robust durability over 20 h of continuous HER operation in acidic solutions. Our investigation provides the synthesis of tunable metal dichalcogenide hybrid structures with better electrochemical performance.

A vertical WSe2–MoSe2 p–n heterostructure with tunable gate rectification

Here, we report the synthesis of a vertical MoSe2/WSe2 p–n heterostructure using a sputtering-CVD method. Unlike the conventional CVD method, this method produced a continuous MoSe2/WSe2 p–n heterostructure. WSe2 and MoSe2 back-gated field effect transistors (FETs) exhibited good gate modulation behavior, and high hole and electron mobilities of ∼2.2 and ∼15.1 cm2 V−1 s−1, respectively. The fabricated vertical MoSe2/WSe2 p–n diode showed rectifying I–V behavior with back-gate tunability. The rectification ratio of the diode was increased with increasing gate voltage, and was increased from ∼18 to ∼1600 as the gate bias increased from −40 V to +40 V. This is attributed to the fact that the barrier height between p-WSe2 and n-MoSe2 is modulated due to the back-gate bias. The rectification ratio is higher than the previously reported values for the TMDC p–n heterostructure grown by CVD.

Correction: A vertical WSe2–MoSe2 p–n heterostructure with tunable gate rectification

Correction for ‘A vertical WSe2–MoSe2 p–n heterostructure with tunable gate rectification’ by Hailing Liu et al., RSC Adv., 2018, 8, 25514–25518.