TD-DFT Simulation and Experimental Studies of a Mirrorless Lasing of Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)].

In this work, we investigate the TD-DFT simulation, optical, and mirrorless laser properties of conjugated polymer (CP) Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)], also known as (PFO-co-PPV-MEHB) or ADS125GE. TD-DFT calculations were performed for three monomer units with truncated tails using time-dependent density functional theory (TD-DFT) calculations. The calculations showed a highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO) structure and a very high oscillator strength of 6.434 for the singlet-singlet transition at 374.43 nm. Experimentally, the absorption and fluorescence spectra were examined at various concentrations in verity of solvents, such as benzene, toluene, and hexane. The experimental results obtained in hexane were comparable with theoretical UV-VIS spectra calculated under vacuum. Amplified spontaneous emission (ASE) spectra peaked at approximately 509 nm for CO PFO-co-PPV-MEHB in solution and were obtained at suitable concentrations and pump energies. Additionally, the photochemical stability of this CP and coumarin (C510) were compared. Time-resolved spectroscopy (TRS) studies with a sub-nanosecond resolution were performed for the CO under various pump energies. These results showed the excited state dynamics and single-pass optical gain of CO PFO-co-PPV-MEHB.

Antimicrobial and catalytic activities of biosynthesized gold, silver and palladium nanoparticles from Solanum nigurum leaves.

The field of nanobiotechnology and nanomedicine paves way for the use of several nanoparticles. Especially, in biomedical applications, the silver nanoparticles (AgNPs), gold nanoparticles (AuNPs) and palladium nanoparticles (PdNPs) are found most vital and promising, among other nanoparticles. The biomedical activities of these particles mostly depend on their shape, size and distribution. Preparation of these particles in an eco-friendly method is an immediate need of the society. Herein, AuNPs, AgNPs and PdNPs (MNPS) were synthesized by Solanum nigrum Leaves (SNL) extract. The structural and morphological studies were carried out by using TEM, XRD and EDAX, while the optical and chemical properties were studied using UV-visible spectrum and FTIR spectroscopy. The particles obtained were found to possess a FCC (Face Centered Cubic) structure. TEM images of Ag, Au and PdNPs showed spherical well dispersed nanoparticles with average size of 3.46 nm, 9.39 nm and 21.55 nm respectively. The FTIR spectra confirmed polyphenols and antioxidants in SNL extract act as reducing and capping agents respectively in the synthesis of MNPs. The EDX technique confirmed the presence of silver, gold and palladium nanoparticles. Antimicrobial studies noted that the AgNPs have effective inhibition against E. coli. The complete reduction of 4-Nitrophenol and the formation of 4-Aminophenol with the presence of NaBH4 was chosen for the study of catalytic activities of the prepared MNPs. The reduction time of Au and Pd catalyst were smaller compared to that of Ag. This viable preparation method for producing small spherical shaped nanoparticles expected to the applied to the fields of nanomedicine.