Indian Institute of Technology Indore

About: Indian Institute of Technology Indore is a education organization based out in Indore, Madhya Pradesh, India. It is known for research contribution in the topics: Fading & Support vector machine. The organization has 1606 authors who have published 4803 publications receiving 66500 citations.

Amplification or cancellation of Fano resonance and quantum confinement induced asymmetries in Raman line-shapes.

Abstract: Fano resonance is reported here to be playing a dual role by amplifying or compensating for the quantum confinement effect induced asymmetry in Raman line-shape in silicon (Si) nanowires (NWs) obtained from heavily doped n- and p-type Si wafers respectively. The compensatory nature results in a near symmetric Raman line-shape from heavily doped p-type Si nanowires (NWs) as both the components almost cancel each other. On the other hand, the expected asymmetry, rather with enhancement, has been observed from heavily doped n-type SiNWs. Such a system (p- & n-) dependent Raman line-shape study has been carried out by theoretical line-shape analysis followed by experimental validation through suitably designed experiments. A dual role of Fano resonance in n- and p-type nano systems has been observed to modulate Raman spectra differently and reconcile accordingly to enhance and cease the Raman spectral asymmetry respectively. The present analysis will enable one to be more careful while analyzing a symmetric Raman line-shape from semiconductor nanostructures.

Interaction of human serum albumin with liposomes of saturated and unsaturated lipids with different phase transition temperatures: a spectroscopic investigation by membrane probe PRODAN

Abstract: The interaction of human serum albumin (HSA) with liposomes made of saturated and unsaturated phosphocholines having distinctly different phase transition temperatures has been studied using circular dichroism (CD), steady state and time resolved fluorescence spectroscopic techniques. We used 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) as the saturated lipid and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC) as the unsaturated lipid to prepare liposomes. The CD measurement reveals that the liposomes induce some kind of stabilization in HSA. The steady state and time resolved fluorescence spectra of PRODAN (6-propionyl 1,2-dimethylaminonaphthalene) were monitored to unravel the interaction between liposome and HSA. We observed that HSA partially penetrates the liposomes due to hydrophobic interaction and destabilizes the packing order of the lipid bilayer leading to leakage of the probe molecules from the liposome. It was found that HSA preferably penetrates into the liposomes, which are less prehydrated at room temperature. Thus penetration is higher in DPPC and DMPC liposomes as these liposomes are less prehydrated due to higher phase temperature (43 °C and 23 °C respectively). On the other hand HSA has less penetration in DOPC and POPC liposomes because these liposomes are more hydrated owing to lower phase transition temperature (−20 °C and −2 °C respectively). The time resolved fluorescence measurements revealed that penetration of HSA into liposomes brings about release of PRODAN molecules. Incorporation of HSA in all the liposomes results in a significant increase in the rotational relaxation time of PRODAN. This fact confirms that HSA penetrates into the liposome and forms a bigger complex.

(D–π–A)2–π–D–A type ferrocenyl bisthiazole linked triphenylamine based molecular systems for DSSC: synthesis, experimental and theoretical performance studies

Abstract: We have designed and synthesized ferrocenyl (donor) bisthiazole linked triphenylamine (donor) based donor–π–acceptor–π–donor–acceptor (D–π–A)2–π–D–A type dyes D1 and D2 by using Pd-catalyzed Sonogashira cross-coupling and Knoevenagel condensation reactions. Their photophysical, electrochemical and computational studies reveal strong donor–acceptor interaction. Dye sensitized solar cells (DSSCs) based on D1 and D2 exhibit power conversion efficiencies (PCE) of 6.33% and 5.03%, respectively. The higher PCE value of the D1 based DSSC is attributed to its enhanced short-circuit current (Jsc) and open-circuit current (Voc) and fill factor (FF) values because of the strong binding of the anchoring cyanoacrylic acid with the TiO2 surface as compared to the dicyanovinyl unit in D2. Time dependent density functional theory (TD-DFT) calculations at B3LYP level on dyes D1 and D2 were performed, which reveal that both dyes show HOMO−1 → LUMO as a major transition. Computational photovoltaic calculations also reveal that dye D1 has better electron injection (ΔGinject) from ELUMO to the conduction band (CB) of TiO2 as compared to dye D2, which is in good agreement with experimental results.

“Vigna radiata” based green C-dots: Photo-triggered theranostics, fluorescent sensor for extracellular and intracellular iron (III) and multicolor live cell imaging probe

Abstract: Fluorescent C-dots have drawn increasing attention due to their superior properties such as high aqueous solubility, optical absorptivity, favorable biocompatibility and appreciable photoluminescence. Nature offers various precursors for the synthesis of green C-dots like fruits, vegetables, flowers, animal derivatives and many more. Herein, nitrogen doped C-dots (N@VRCD) were developed by economical, one step hydrothermal method using “Vigna radiata” sprouts as sole carbon precursor and ethylenediamine as the nitrogen source, which was optimized for enhanced optical properties. To the best of our knowledge, N@VRCD shows excellent quantum yield ∼58%. Importantly, N@VRCD also exhibits significant light induced phototoxicity to cancerous cells which enable the possibility of using it as a potential theranostics agent. Further, the N@VRCD displays highly sensitive and selective sensing behaviour towards Fe3+ ions by getting fluorescence “turn-off” with the limit of detection as low as 140 nM. Moreover, N@VRCD shows biocompatible and hemocompatible nature with a potential of multicolor live cell imaging and intracellular Fe3+ detection which was validated by confocal microscopy and flow cytometry.