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Although the smaller size of nanophosphors renders processability and flexibility for next-generation devices, concurrent surface prolificity stifles the phosphor efficiency, and in turn, their superiority. To circumvent the surface side effect in the Y2Sn2O7:Eu nanophosphor, the present work articulates a co-substituent (Zr4+)-assisted revival of stifled luminescence. Steady-state and time-resolved photoluminescence studies revealed that with respect to nanophosphors without a Zr substituent, the Zr-substituted Y2Sn2−xZrxO7:Eu (x = 0.25, 0.5) pyrochlore nanophosphor exhibited multi-fold augmentation in lifetime and quantum efficiency values, which are key parameters for ascertaining the photoluminescence performance. The experimental and theoretical outcomes indicate that Eu3+ prefers to be in close proximity to Zr4+ ions in the Y2Sn2−xZrxO7:Eu (x = 0.25, 0.5) pyrochlore lattice to counterbalance the individual substitution consequences and generate appropriate electronic distributions and polar interactions. This proximity preference of Zr–Eu facilitates the occupation of Eu3+ in the interior region of nanoparticles and avoids the surface sensitivity. Furthermore, the lifetime values for the Y2Sn2−xZrxO7:Eu (x = 0.25, 0.5) pyrochlore nanophosphor are 5–6 ms, and the internal quantum efficiency is approximately 80%, which is the highest of any pyrochlore nanosized phosphor reported thus far, to the best of our knowledge. Thus, this work deciphered an innovative pathway for evasion of the surface-quenching effect without compromising homogeneity in the structural ordering and vicinal symmetry of the dopant/substituent across the dimensions of nanophosphors. [ABSTRACT FROM AUTHOR]

In the realm of metallaphotocatalytic C−H activation strategy, the direct excitation of the transition metal which plays the dual role of light energy harnessing alongside performing the bond breaking and forming is a rare phenomenon. In this context we have developed the first photo‐induced Rh‐catalyzed ortho‐alkynylation under ambient conditions without the requirement of silver salt, photocatalyst (PC) or any engineered substrate or catalyst. The transformation functions by the specific cooperative effect of a six‐membered rhodacycle which is the photo‐responsive species. The catalytic system allows the conjugation of arenes with sp3‐rich pharmacophoric fragments. The control experiments as well as the computational studies resolve the mechanistic intricacies for this transformation. An outer sphere electron transfer process from Rh to alkynyl radical is operative for the present photo‐induced transformation over the more common oxidative addition or 1,2‐migratory insertion pathways. [ABSTRACT FROM AUTHOR]

Fluorescence-based sensing of bio-analytes is a hitherto emerging area in contemporary research, as the technique offers several advantageous features like non-invasiveness, high selectivity, high sensitivity, rapid responses in addition to its widespread applications in biologically important samples. Herein, we present a perspective on different underlying mechanisms, which play key roles in the luminescence-based sensing along with some recent progresses made across the globe in estimating bio-analytes like amino acids, ATP, protamine, sulfite, etc. This review comprises a comparative discussion on modulations in optical properties of different fluorescent probes by the presence of target analytes, highlighting their detection limits in analyte sensing. With the extensive coverage made in this article on fluorescence-based bio-analyte detections, covering mainly the various developments mostly after 2010, it is anticipated to make this review article quite unique and propitious to the impending academic and applied research in this subject domain on the years to come. [Display omitted] • This review discusses briefly about different fluorescence based sensing mechanism. • Gives a brief overview of different fluorescent probes used for various bio-analytes. • Provides a comparative evaluation of fluorescent probes used for a bio-analyte. • Inculcate the use of luminescence-based techniques for futuristic applications. [ABSTRACT FROM AUTHOR]

Even though technological relevance for nuclear and oxide fuel cell application has persuaded a large number of investigations on the Y 2 Zr 2 O 7 system, its local structure still remains ambiguous and debatable. While diffraction-based investigations claim a lack of local ordering, the MAS NMR and Raman spectroscopic investigations speculate the presence of local ordering. Besides, a correlation between the local and global structures of Y 2 Zr 2 O 7 is also missing to date. Present work attempts to get deeper insights into the local structure of Y 2 Zr 2 O 7 and correlate the local structure with global disordering. Complementary investigation using multiple strategies (XRD, RAMAN, electron microscopy, DFT calculations) revealed the presence of pyrochlore-like features in globally disordered Y 2 Zr 2 O 7 . Globally distributed "local probe ions" (Sn 4+ by MAS NMR and Eu 3+ by photoluminescence (PL)) were utilized for establishing the correlation between local and global structures. The 119 Sn MAS NMR spectra possess the shoulder peak bearing chemical shift values, which are improbable under complete cationic randomization. The emission and decay profiles of the Eu 3+ ion recommend positioning of few probe ions at the centrosymmetric site, which was further reinforced by crystal field splitting and lifetime values. Thus, both NMR and PL results reaffirm the existence of a pyrochlore-like atomic arrangement in predominantly defective fluorite Y 2 Zr 2 O 7 phase. These discernible pyrochlore-like features have been envisaged to be emanating from unevenness in bond strength and ionicity/covalency of Y-O and Zr-O bonds. Cationic and anionic randomization energetically endorses global disordering, but the bonding disparity induces short-range ordering. It is believed that the presented findings will guide future research in regulating the physicochemical properties of Y 2 Zr 2 O 7 for the target applications.