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Er 3+ and Yb 3+ doped CaTiO 3 phosphors were synthesized via the solution combustion method and analyzed for structural, morphological, and optical properties using X-ray powder diffraction, field emission scanning electron microscopy, and photoluminescence spectroscopy. The Er 3+ ions showed green and red emissions when excited by a 980 nm infrared source. Power-dependent emission spectra were used to study the up-conversion process, and a rate equation model was proposed for clarity. For temperature sensing, the phosphor's temperature-dependent emission lines were examined between 303 and 583 K. This analysis was conducted using the fluorescence intensity ratio method. Relative sensitivities of 1.14%, 1.66%, 0.15%, and 0.33% K -1 were observed for various thermally and non-thermally linked transitions. The phosphor also demonstrated potential for molecular logic gate applications, achieving switching ratios of ~ 170.86% for the AND gate and ~ 72.28% for the INHIBIT gate when heat and IR excitation were used as inputs. This material shows promise for both optical thermometry and future molecular logic devices., Competing Interests: Declarations. Competing Interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Carbon quantum dots (CQDs) were synthesized in this study by hydrothermally treating cow milk. The procedure is simple, non-hazardous to the environment, and does not necessitate the use of any special instruments or chemicals. CQDs were practically almost circular when they were manufactured and had an average size of 7 nm. Carbon (67.36%), oxygen (22.73%), and nitrogen (9.91%) comprised the majority of their composition. They feature broad excitation-emission spectra, excitation-dependent emission, and temperature-dependent photoluminescence. They remained quite stable in the presence of a lot of salt, UV radiation, and storage time. Because luminescence quenching mechanisms are sensitive to and selective for Sn 2+ , they can be employed to create a nanosensor for detecting Sn 2+ ., (© 2022. The Author(s).)

Nano phosphors have been prepared with 1 mol% and 5 mol% doping of Eu in vanadate by sol-gel method. X-ray pattern indicated that nano phosphors did not lead to phase change and has tetragonal crystal structure. Excitation spectra revealed that the band at 308 nm arises due to the charge transfer transitions among Eu(3+) and VO4 (3-) ions. The peak position of fluorescence shifted from 518 to 638 nm on varying the excitation wavelength from 257 nm to 318 nm. It is also noticed that the fluorescence intensity increases with the rise of calcination temperatures of the samples.

The interaction of Citrate-capped gold nanoparticles (AuNPs) with Bovine gamma globulin (BGG) was studied using Fourier transform infrared (FTIR), UV-Visible and Fluorescence spectroscopy. FTIR has confirmed the conjugation of AuNPs and BGG. Fluorescence quenching of tryptophan has confirmed the strong interaction between BGG and AuNPs. UV-Visible and Fluorescence spectroscopy have investigated the extent of interaction by determining the binding constants. Binding constants evaluated from UV-Visible and Fluorescence data are in good agreement with each other. An independent class of binding site on BGG for AuNPs has been predicted, where AuNPs interact with a highly solvent accessible tryptophan residue.