Author
Harminder Singh
Other affiliations: Indian Institute of Technology Kanpur, Allahabad University
Bio: Harminder Singh is an academic researcher from Guru Nanak Dev University. The author has contributed to research in topics: Nanogenerator & Reaction rate. The author has an hindex of 10, co-authored 34 publications receiving 387 citations. Previous affiliations of Harminder Singh include Indian Institute of Technology Kanpur & Allahabad University.
Papers
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TL;DR: In this article, weak excited state intramolecular proton transfer (ESIPT) based emission in CH3CN and their binary mixtures with water, but in solutions containing >70% water fraction, DPPS-1 and DPPSs-2 molecules aggregate and give a strong green ESIPT emission at 526 nm (ϕ = 0273, 0068).
Abstract: Diphenylpyrimidinone–salicylideneamine DPPS-1 undergoes concentration dependent self-assembly to form aggregates with rods – mimicking a ‘coral reef’ superstructure and a spherical morphology evident from dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) DPPS-1 and DPPS-2 exhibit weak excited state intramolecular proton transfer (ESIPT) based emission in CH3CN and their binary mixtures with water, but in solutions containing >70% water fraction DPPS-1 and DPPS-2 molecules aggregate and ESIPT is facilitated to give a strong green ESIPT emission at 526 nm (ϕ = 0273, 0068) The ESIPT process remains active in the solid state and solid DPPS-1 and DPPS-2 appear as fluorescent green under 365 nm light illumination The AIE-active nature of DPPS-1 and DPPS-2 finds applications in the visualization of latent fingerprints on aluminium, steel and glass surfaces Even 24 h after the placement of the fingerprints, up to the second level of information viz core, lake, ridge termination and dots, delta and bifurcation in the fingerprints could be identified
77 citations
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TL;DR: In this article, a triple-signaling mechanism, namely, internal charge transfer (ICT), CN rotation and excited state intramolecular proton transfer (ESIPT), has been used for the construction of INHIBIT (INH), IMPLICATION (IMP), AND, NOR, YES and NOT logic gates using Cu2+ and acetate as inputs and absorbance/emission as outputs.
Abstract: Chemosensor 1 shows three different responses towards Cu2+, acetate and Cu(OAc)2 ion pair at different wavelengths independently in its absorption and fluorescence behaviour following a triple-signaling mechanism, namely, internal charge transfer (ICT), CN rotation and excited state intramolecular proton transfer (ESIPT). Chemosensor 1 shows a blue shift of the absorption band from 337 nm to 308 nm in the presence of Cu2+ ions (ICT). It exhibits a fluorescence ‘turn-off’ response at λem 458 nm in the presence of 1 equivalent of Cu2+ ions. The further addition of Cu2+ (6 equivalents) results in ∼24 times enhancement in the emission intensity at λem 427 nm, mimicking an ‘ON–OFF–ON’ molecular switch (ESIPT and CN rotation). The addition of acetate ions to a solution of 1 results in a red shift of the absorption band from 337 to 360 nm (ICT) and ∼4 times enhancement of the emission intensity at λem 458 nm (ESIPT). On the addition of a Cu(OAc)2 ion pair, 1 shows the apparent effect of Cu2+ (blue shift, 337 to 308 nm) and acetate (red shift, 337 to 380 nm), which indicates the synergistic effect of both Cu2+ and AcO− on each other's binding. The potential application of chemosensor 1 for the construction of INHIBIT (INH), IMPLICATION (IMP), AND, NOR, YES and NOT logic gates using Cu2+ and acetate as the inputs and absorbance/emission as the outputs is elaborated.
54 citations
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TL;DR: In this article, a series of new bis-calix[4]arenes with imine units was synthesized by using a simple condensation procedure, and two of them were tested as sensors in solid-state electrodes.
46 citations
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41 citations
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TL;DR: The self-assembled diphenylpyrimidinone (DPSA) derivative showed aggregation-induced emission (∼24 fold) in a > 90% H2O:CH3CN mixture with orange-red fluorescence (λmax 564 nm) as mentioned in this paper.
Abstract: Fluorescent molecules are extensively employed in (bio)sensing and bioimaging but their applications in the visualization of fingerprints are less reported due to their inherited aggregation-caused quenching (ACQ) mechanism in the solid state (aggregated form). DPSA undergoes self-assembly to form aggregates with rod-like structures in a 90% H2O : CH3CN mixture evident from dynamic light scattering (DLS) and scanning electron microscopic (SEM) techniques. The self-assembled diphenylpyrimidinone (DPSA) derivative shows aggregation-induced emission (∼24 fold) in a >90% H2O : CH3CN mixture with orange-red fluorescence (λmax 564 nm). The red fluorescent aggregates of DPSA show applications in the visualization of latent fingerprints on aluminium, stainless steel and metal currency coin substrates. In addition, we established the individuality of three subjects based on information gathered at level one (pattern of arch, loop or whorl) and level two (minutiae details of dots, bifurcation, ridge ending, core and delta).
32 citations
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295 citations
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TL;DR: In this paper, a linear equation correlating logarithms of imine formation constants with pKa and HOMO energies of amines and LUMO energy of aldehydes is proposed.
219 citations
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TL;DR: In this article, the most recent developments of designing, modification, processing and integration of cellulose-based piezoelectric nanogenerators (PENGs), TENGs, and hybrid PENG/TENGs for energy harvesting and other applications are reviewed in detail.
Abstract: Cellulose is the most earth-abundant natural polymer resource, which with combined eco-friendly and extraordinary sustainable properties such as renewability, biodegradability, low cost and excellent biocompatibility has been widely used by humans for thousands of years. In the past few years, many novel cellulosic materials and their unique applications have been developed including the recent research focus on energy harvesting. The high crystallization and plentiful polar hydroxyl groups endow cellulose with a large number of dipoles and strong electron donating capacity, resulting in a promising potential of piezoelectric and triboelectric effects. However, there is no review about cellulose-based nanogenerators until now. In this paper, the most recent developments of designing, modification, processing and integration of cellulose-based piezoelectric nanogenerators (PENGs), triboelectric nanogenerators (TENGs) and hybrid piezo/triboelectric nanogenerators (PTENGs) for energy harvesting and other applications are reviewed in detail. For cellulose-based PENGs, representative basic piezoelectric cellulose and recent research on PENG devices are discussed. For cellulose-based TENGs, several effective strategies including rough modification of contact surface, addition of electronic functional fillers and chemical modification for improving the output performance are further summarized. Meanwhile, the latest cellulose-based hybrid PTENG is also introduced from the fundamental design to the investigations on enhanced strategies. The opportunities and challenges of these cellulose-based nanogenerator devices are put forward in the final part, which could enable this up-to-date and state-of-the-art review to be an effective guidance for the future research on cellulose-based nanogenerators in energy harvesting.
137 citations
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TL;DR: A new ion-selective PVC membrane electrode based on salicylaldehyde thiosemicarbazone as an ionophore is developed successfully as sensor for mercury(II) ions and shows excellent potentiometric response characteristics.
126 citations
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TL;DR: A water-soluble probe TPA-1OH with aggregation-induced emission (AIE) activity is synthesized and used for expedient real-time fluorescence in situ visualization of latent fingerprints (LFPs) and the Level 3 details of LFPs are evidently visible under fluorescence microscopy.
Abstract: A water-soluble probe, TPA-1OH, with aggregation-induced emission activity is synthesized and used for expedient real-time fluorescence in situ visualization of latent fingerprints (LFPs). A TPA-1O...
119 citations