Acquiring fundamental knowledge of properties of actinide‐based materials is a necessary step to create new possibilities for addressing the current challenges in the nuclear energy and nuclear waste sectors. In this report, we established a photophysics–electronics correlation for actinide‐containing metal‐organic frameworks (An‐MOFs) as a function of excitation wavelength, for the first time. A stepwise approach for dynamically modulating electronic properties was applied for the first time towards actinide‐based heterometallic MOFs through integration of photochromic linkers. Optical cycling, modeling of density of states near the Fermi edge, conductivity measurements, and photoisomerization kinetics were employed to shed light on the process of tailoring optoelectronic properties of An‐MOFs. Furthermore, the first photochromic MOF‐based field‐effect transistor, in which the field‐effect response could be changed through light exposure, was constructed. As a demonstration, the change in current upon light exposure was sufficient to operate a two‐LED fail‐safe indicator circuit.

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We report the first comprehensive study on the purification of PbS quantum dots (QDs) using gel permeation chromatography (GPC). GPC enables the efficient and repeatable separation of unbound small molecules from QDs in a homogeneous solvent environment. This separation allows us to gain further insight into the surface capping layer of PbS QDs and measure the ligand density on QDs of different sizes. We find that small oleate-capped PbS QDs are stable in solution in toluene after purification by GPC with negligible free ligand concentrations. However, purification of larger-diameter QDs reveals two oleate populations that persist after multiple GPC purifications: one with a broad olefin resonance characteristic of strongly bound ligands in smaller QDs, and the other with a narrower peak suggesting dynamic exchange with freely diffusing species. Variable-temperature NMR indicates a reversible equilibrium between the two populations, which is also observed in samples purified through precipitation with a polar solvent. The observation of two oleate populations following GPC purification is maintained even when the large-diameter QDs are formed using a strictly anhydrous procedure that should eliminate the presence of water, hydroxide, or oleic acid in as-synthesized samples. In conducting this strictly anhydrous synthesis, we incidentally observe that water plays a role in determining the resultant size of PbS QDs prepared by traditional methods compared to their anhydrous analogues. Understanding how the surfaces of PbS QDs are terminated should aid in interpreting their behavior in subsequent ligand exchange steps as necessary for diverse applications.

Salinity is one of the major agricultural concern that significantly limits the crop productivity. The plant growth promoting rhizobacteria (PGPR) may contribute in sustainable crop production under salt stress. The current study was designed to isolate the Indole Acetic Acid (IAA) producing salt tolerant PGPR to promote the growth of cotton ( Gossypium hirsutum , FH-142) and induce its salt stress tolerance. Ten Salt Tolerant (ST) bacterial strains were screened for their PGP trait in vitro and evaluated for their beneficial effect on cotton plants growth by plant–microbe interaction assay in lab and under natural condition. GC–MS analysis of the metabolites of the selected bacterial strains confirmed the presence of indolic compounds like indole, indole-3-butyramide, benzylmalonic acid and 4-methyl-2-pyrrolidinone. The bacterial isolates ST4, ST5, ST6, ST15, ST16, ST17, ST18, ST20, ST22 and ST25 were identified as Bacillus sp., B. sonorensis , B. cereus , B. subtilis, Brevibacillus sp. B. safensis , B. paramycoides, Bacillus sp., B. cereus and B. tequilensis respectively on the basis of 16S rDNA sequencing. Bacteria inoculated plants had a significant (P < 0.05) increase in percentage germination up to (31%), root length (17%) and shoot length (34%) in lab while in wire house pot experiments, maximum enhancement in root length (31%) and shoot length (29%) was observed. ST bacterial strains inoculation improved the chlorophyll content index (34%), relative water content (36%), leaf area (33%), absorption of K + (28%) and decreased the uptake of Na + (58%) from soil in plants under salt stress over control in pot experiment. These ST PGPR have the potential to act as plant defense agents by enhancing plant growth, productivity, and tolerance in saline environment.

Nano materials with high surface area increase the kinetics and extent of the redox reactions, thus resulting in high power and energy densities. In this study high surface area zinc oxide nanorods have been synthesized by surfactant free ethylene glycol assisted solvothermal method. The nanorods thus prepared have diameters in the submicron range (300∼500 nm) with high aspect ratio. They have uniform geometry and well aligned direction. These nanorods are characterized by XRD, SEM, Specific Surface Area Analysis, solubility in alkaline medium, EDX analysis and galvanostatic charge/discharge studies in Zn/AgO batteries. The prepared zinc oxide nanorods have low solubility in alkaline medium with higher structural stability, which imparts the improved cycle life stability to Zn/AgO cells.

We demonstrate photovoltaic and photoconductive responses to near-infrared light in devices formed by depositing a film of gel permeation chromatography purified PbS quantum dots (QDs) on top of n-SiC epitaxial layers with natively grown, low-leakage 10–15 monolayer thick epitaxial graphene (EG) Schottky contacts. The QD film layer was removable by selective chemical etching, resetting the EG/SiC Schottky diode: the sub-bandgap response could be restored in subsequent PbS-QD depositions. The EG in these devices simultaneously forms Schottky contacts to SiC and ohmic contacts to PbS-QD, enabling electrical screening and isolation of these interfaces from each other. After PbS-QD deposition, the diodes exhibit photovoltaic and photoconductive responses at photon energies far below the SiC bandgap, extending to the NIR gap of the QD film. Scanning photocurrent microscopy illustrates that this is due to charge transfer from the QD film to the n-type 4H-SiC through a trap-limited, rectifying PbS-QD/SiC heterojunction with ideality n = 2 in parallel with the EG/SiC Schottky diode. The photoconductive gain at this QD/SiC interface could be useful for IR detection in wide-bandgap platforms. Response times as fast as 40 ms are suitable for imaging applications, although careful contact design is required to optimize work-function matching and spreading resistance.

A highly stable p-type PbS-QDs ink is prepared using a single-step biphasic ligand exchange route, overcoming instability encountered in previous reports. Chemical characterization of the ink reveals 3-mercaptopriopionic acid (MPA)...

Colloidal quantum dots (QDs) are attractive fluorophores for bioimaging and biomedical applications because of their favorable and tunable optoelectronic properties. In this study, the native hydrophobic ligand environment of oleate-capped sphalerite CdSe/ZnS core/shell QDs was quantitatively exchanged with a set of imidazole-bearing small-molecule ligands. Inductively coupled plasma-optical emission spectroscopy and 1H NMR were used to identify and quantify three different ligand exchange processes: Z-type dissociation of the Zn­(oleate)2, L-type association of the imidazole, and X-type anionic exchange of oleate with Cl–, all of which contributed to the overall ligand exchange.