Publications

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Three benzodipyrrole (BDP)‐based organic small molecules with substituted 4‐methoxyphenyl (CB‐1), 3‐fluorophenyl (CB‐2), and 3‐trifluoromethylphenyl (CB‐3) are designed, synthesized, and used as a hole‐transporting material (HTM) for perovskite solar cells (PSCs). The electrochemical, optical, thermal, electronic, and optoelectronic properties of the HTMs are characterized to verify their suitability for PSCs. The terminal functional groups of the HTMs having different heteroatoms mainly target effective defect passivation of perovskites. Photoluminescence studies and molecular dynamic simulations reveal that fluorine atoms within CB‐2 and CB‐3 can contribute to the defect passivation via interaction with Pb of the perovskite. In particular, a highly planar conformation of CB‐2 on the perovskite surface can facilitate more efficient hole transfer at the interface. Thus, the PSCs employing CB‐2 achieve the highest power conversion efficiency (PCE) of 18.23% while the devices using CB‐1 and CB‐3 exhibit a lower PCE of 16.78% and 16.74%, respectively. PSCs with the BDP‐based HTMs demonstrate excellent long‐term storage stability without degradation in their PCEs over 6 months. The highly planar geometry, defect passivation effect, and hydrophobicity of CB‐2 show its great potential as an HTM for efficient and stable PSCs.

The synthesis of NH3 heavily relies on the Haber-Bosch process suffering from a large amount of CO2 emission and energy consumption. Possessing eco-friendly and sustainable characteristics, electrochemical reduction is considered as a promising candidate for artificial N2 fixation under ambient conditions, but efficient electrocatalysts are crucial for the N2 reduction reaction (NRR). In this communication, we report that perovskite La2Ti2O7 nanosheets behave as an efficient NRR electrocatalyst with excellent selectivity under ambient conditions. In 0.1 M HCl, this catalyst achieves a high NH3 yield rate of 25.15 μg h-1 mgcat.-1 with a faradaic efficiency of 4.55% at -0.55 V vs. a reversible hydrogen electrode. Notably, it also shows high electrochemical stability.

Hollow microflowers-like ZnS/CuS@C heterojunction as an anode material for sodium storage delivers large reversible capacity, ultralong cycling life and competitive rate capability.

It is highly attractive but challenging to develop earth-abundant electrocatalysts for energy-saving electrolytic hydrogen generation. Herein, we report that Ni₂ P nanoarrays grown in situ on nickel foam (Ni₂ P/NF) behave as a durable high-performance non-noble-metal electrocatalyst for hydrazine oxidation reaction (HzOR) in alkaline media. The replacement of the sluggish anodic oxygen evolution reaction with such the more thermodynamically favorable HzOR enables energy-saving electrochemical hydrogen production with the use of Ni₂ P/NF as a bifunctional catalyst for anodic HzOR and cathodic hydrogen evolution reaction. When operated at room temperature, this two-electrode electrolytic system drives 500 mA cm^-2 at a cell voltage as low as 1.0 V with strong long-term electrochemical durability and 100 % Faradaic efficiency for hydrogen evolution in 1.0 m KOH aqueous solution with 0.5 m hydrazine.

ABSTRACT In this study, the skin of the beavertail cactus, Opuntia Basilaris , was used for the isolation of cellulose nanofibers using a chemo‐mechanical technique. It was shown that the skins had a relatively high cellulose content, whereas their lignin content was low. Fourier transform infrared spectroscopy and X‐ray diffraction proved that the isolation of cellulose nanofibers from the amorphous components of the skins was performed successfully. The cactus skins were also shown to have a high content of calcium oxalate crystals. Morphological observations proved that the isolated cellulose fibers had diameters in the range of 10–50 nm. It was shown that the addition of nanofibers increased the modulus and strength of the polyvinyl alcohol matrix significantly, whereas the elongation at break decreased. Thermogravimetric analysis proved that: (i) isolated nanofibers had higher thermal stabilities than the cactus skins, and (ii) inclusion of nanofibers increased the stability of polyvinyl alcohol noticeably. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42499.

Wormhole-like hexagonal mesoporous silica (HMS) can modify the perovskite morphology and increase the light path length in a planar junction perovskite solar cell to improve the average PCE to 17.6% over 30 devices.

The design, fabrication and investigation of the graphene-In-SnO2 (indium tin oxide (ITO)) based bilayer semitransparent thermoelectric cells are described. The cells were fabricated by encapsulating the graphene powder in the form of narrow strips on the transparent flexible plastic substrates covered by ITO. Between the parallel graphene strips, there were transparent ITO strips of the same width. This structure made the thermoelectric cells semitransparent. It was observed that Seebeck coefficient and figure of merit of the thermoelectric cell increased with temperature. The output voltage of the cells also increased with increase in gradient of temperature. The obtained results may be used for the development of the semitransparent solar thermoelectric cells because this technology is cheaper and simple as compared to semitransparent solar cells technologies.

Developing earth-abundant and high-performance electrocatalysts toward the alkaline hydrogen evolution reaction (HER) is highly desired. In this communication, we report a Mn-doped Ni₂P nanosheet array on nickel foam (Mn-Ni₂P/NF) as a high-efficiency electrocatalyst for the HER in alkaline solutions. This Mn-Ni₂P/NF can drive 20 mA cm^-2 at an overpotential of 103 mV in 1.0 M KOH, which is 82 mV less than that for Ni₂P/NF. In addition, it also demonstrates excellent long-term electrochemical durability for at least 25 h. This work offers us a promising catalyst material for water-splitting devices for large-scale production of hydrogen fuels.

We report here a comparative theoretical and experimental study of four triazine-based hydrazone derivatives. The hydrazones are synthesized by a three step process from commercially available benzil and thiosemicarbazide. The structures of all compounds were determined by using the UV-Vis., FT-IR, NMR (1H and 13C) spectroscopic techniques and finally confirmed unequivocally by single crystal X-ray diffraction analysis. Experimental geometric parameters and spectroscopic properties of the triazine based hydrazones are compared with those obtained from density functional theory (DFT) studies. The model developed here comprises of geometry optimization at B3LYP/6-31G (d, p) level of DFT. Optimized geometric parameters of all four compounds showed excellent correlations with the results obtained from X-ray diffraction studies. The vibrational spectra show nice correlations with the experimental IR spectra. Moreover, the simulated absorption spectra also agree well with experimental results (within 10-20 nm). The molecular electrostatic potential (MEP) mapped over the entire stabilized geometries of the compounds indicated their chemical reactivates. Furthermore, frontier molecular orbital (electronic properties) and first hyperpolarizability (nonlinear optical response) were also computed at the B3LYP/6-31G (d, p) level of theory.

An Fe–TiO 2 nanoribbon array supported on a Ti plate is a high-efficiency catalyst for electrocatalytic NO 3 − -to-NH 3 conversion, capable of achieving a large NH 3 yield of up to 940.17 μmol h −1 cm −2 and a high faradaic efficiency of 95.93%.