High Electrical Conductivity and Hole Transport in an Insightfully Engineered Columnar Liquid Crystal for Solution-Processable Nanoelectronics.

Discotic liquid crystals (DLCs) are widely acknowledged as a class of organic semiconductors that can harmonize charge carrier mobility and device processability through supramolecular self-assembly. In spite of circumventing such a major challenge in fabricating low-cost charge transport layers, DLC-based hole transport layers (HTLs) have remained elusive in modern organo-electronics. In this work, a minimalistic design strategy is envisioned to effectuate a cyanovinylene-integrated pyrene-based discotic liquid crystal (PY-DLC) with a room-temperature columnar hexagonal mesophase and narrow bandgap for efficient semiconducting behavior. Adequately combined photophysical, electrochemical, and theoretical studies investigate the structure-property relations, logically correlating them with efficient hole transport. With a low reorganization energy of 0.2 eV, PY-DLC exhibits superior charge extraction ability from the contact electrodes at low values of applied voltage, achieving an electrical conductivity of 3.22 × 10-4 S m-1, the highest reported value for any pristine DLC film in a vertical charge transport device. The columnar self-assembly, in conjunction with solution-processable self-healed films, results in commendably elevated values of hole mobility (≈10-3 cm2 V-1s-1). This study provides an unprecedented constructive outlook toward the development of DLC semiconductors as practical HTLs in organic electronics.

Coordination Structure Modulation in Group-VIB Metal Doped Ag3PO4 Augments Active Site Density for Electrocatalytic Conversion of N2 to NH3.

Doping is considered a promising material engineering strategy in electrochemical nitrogen reduction reaction (NRR), provided the role of the active site is rightly identified. This work concerns the doping of group VIB metal in Ag3PO4 to enhance the active site density, accompanied by d-p orbital mixing at the active site/N2 interface. Doping induces compressive strain in the Ag3PO4 lattice and inherently accompanies vacancy generation, the latter is quantified with positron annihilation lifetime studies (PALS). This eventually alters the metal d-electronic states relative to Fermi level and manipulate the active sites for NRR resulting into side-on N2 adsorption at the interface. The charge density deployment reveals Mo as the most efficient dopant, attaining a minimum NRR overpotential, as confirmed by the detailed kinetic study with the rotating ring disk electrode (RRDE) technique. In fact, the Pt ring of RRDE fails to detect N2H4, which is formed as a stable intermediate on the electrode surface, as identified from in-situ attenuated total reflectance-infrared (ATR-IR) spectroscopy. This advocates the complete conversion of N2 to NH3 on Mo/Ag3PO4-10 and the so-formed oxygen vacancies formed during doping act as proton scavengers suppressing hydrogen evolution reaction resulting into a Faradaic efficiency of 54.8% for NRR.

Brachytherapy at the nanoscale with protein functionalized and intrinsically radiolabeled [169Yb]Yb2O3 nanoseeds.

PURPOSE: Classical brachytherapy of solid malignant tumors is an invasive procedure which often results in an uneven dose distribution, while requiring surgical removal of sealed radioactive seed sources after a certain period of time. To circumvent these issues, we report the synthesis of intrinsically radiolabeled and gum Arabic glycoprotein functionalized [169Yb]Yb2O3 nanoseeds as a novel nanoscale brachytherapy agent, which could directly be administered via intratumoral injection for tumor therapy. METHODS: 169Yb (T½ = 32 days) was produced by neutron irradiation of enriched (15.2% in 168Yb) Yb2O3 target in a nuclear reactor, radiochemically converted to [169Yb]YbCl3 and used for nanoparticle (NP) synthesis. Intrinsically radiolabeled NP were synthesized by controlled hydrolysis of Yb3+ ions in gum Arabic glycoprotein medium. In vivo SPECT/CT imaging, autoradiography, and biodistribution studies were performed after intratumoral injection of radiolabeled NP in B16F10 tumor bearing C57BL/6 mice. Systematic tumor regression studies and histopathological analyses were performed to demonstrate therapeutic efficacy in the same mice model. RESULTS: The nanoformulation was a clear solution having high colloidal and radiochemical stability. Uniform distribution and retention of the radiolabeled nanoformulation in the tumor mass were observed via SPECT/CT imaging and autoradiography studies. In a tumor regression study, tumor growth was significantly arrested with different doses of radiolabeled NP compared to the control and the best treatment effect was observed with ~ 27.8 MBq dose. In histopathological analysis, loss of mitotic cells was apparent in tumor tissue of treated groups, whereas no significant damage in kidney, lungs, and liver tissue morphology was observed. CONCLUSIONS: These results hold promise for nanoscale brachytherapy to become a clinically practical treatment modality for unresectable solid cancers.

Autocombustion Route Derived Zinc Ferrite Nanoparticles as Chemiresistive Sensor for Detection of Alcohol Vapors.

Prolonged exposure to alcohol vapors can have detrimental effects on human health, potentially leading to eye irritation, dizziness, and in some cases, damage to the nervous system. The present article aims to provide a comprehensive understanding on the synthesis and characterization of zinc ferrite (ZnFe2O4) nanoparticles, as well as their interactions with a range of alcohol vapors, including methanol, ethanol, n-propanol, and isopropanol. These alcohols differ in their molecular weight, boiling points, diffusivity, and other properties. The study reveals the semiconducting ZnFe2O4 nanoparticulate sensor's capability for reversible, repeatable, and sensitive detection of alcohol vapors. The sensor exhibits the highest response to ethanol within operating temperature range (225-300 °C). An attempt is made to establish a correlation between the properties of the target analytes and the observed sensing signals. Additionally, the response conductance transients of ZnFe2O4 under the exposure to the studied alcohol vapors are modeled based on the Langmuir-Hinshelwood adsorption mechanism. The characteristic time constants obtained from this modeling are justified with respect to the properties of the analytes.

Composition-dependent photoluminescence in nanocrystalline La2Hf2-xZrxO7:Eu phosphor: role of chemical twin Zr/Hf environments around a luminescent center.

Based on chemical intuition, linear trends are anticipated in Eu3+ photoluminescence performance inside a pyrochlore matrix of the chemical twins, Hf and Zr, owing to probable geometrical and chemical similarity around the luminescent center. The present work reports the drastically fluctuating result of doping Eu3+ in nanocrystalline pyrochlore, La2Hf2-xZrxO7 (LHZO), matrix on composition variation; the variation is counter to the anticipation-based chemical brotherhood of Hf and Zr. Zirconium-enriched samples of LHZO improve asymmetry around Eu3+ ion leading to enhanced photoluminescence quantum yield (PLQY). The samples with compositions 0.7Hf and 1.3Zr depict the lowest non-radiative channels with the highest theoretically calculated PLQY of ∼71% and excellent thermal stability (∼91%). Synergistic experimental and theoretical analysis reveals that Eu does not unbiasedly occupy La-sites in the pyrochlore LHZO matrix towards chemical twins of Hf and Zr; rather, it energetically prefers to occupy Zr-rich vicinal sites. When the composition with Zr is in the low-medium range, Eu has a higher probability of occupying Zr-rich vicinal sites depicting higher lifetime and PLQY. When Zr-content goes beyond 70-80%, the other site occupancies start contributing leading to a reduction in both lifetime and quantum yield. This work paves a great strategy and provides a futuristic potential to utilize europium luminescence in separating chemically close Hf-Zr for various technological applications.

Electrocatalytic OER behavior of the Bi-Fe-O system: an understanding from the perspective of the presence of oxygen vacancies.

This study aims to understand and correlate the role of the nature and relative concentration of oxygen vacancies with the trend observed in the OER with the Bi-Fe-O system. To understand this, we first investigated the system of oxides using X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR), which revealed the presence of oxygen vacancies in the system. Density functional theory (DFT) was employed to investigate the relative concentration of these vacancies by calculating their formation energies. Positron annihilation lifetime spectroscopy (PALS) was carried out to understand the nature of these oxygen vacancies. We observed that the presence of a higher concentration of monovacancies created due to the absence of oxygen from the structure of Bi2Fe4O9 was mainly responsible for the high performance of the oxide towards the OER compared to that of the other oxides viz-BiFeO3 and Bi25FeO40 of the Bi-Fe-O system.

Color tunable luminescence in ThO2:Er3+,Yb3+ nanocrystals: a promising new platform for upconversion.

Lanthanide-doped luminescent nanoparticles are an appealing system for many applications in the area of biomedical, solar cell, thermometry, anti-counterfeiting, etc. due to their sensitivity, reliability, high photochemical stability, and high optical transparency in the visible-NIR range. A color-tunable upconversion-luminescence (UCL) in a new low phonon energy ThO2 host based on modulating sensitizer concentration has been realized in this work and it may work as a potential candidate to replace corrosive and toxic fluoride based hosts in the future. Er3+-Yb3+ co-doped thoria nanoparticles were prepared using a gel combustion route and their structural and luminescence properties were determined as a function of the Yb3+ concentration. Phonon dispersion measurements have established the dynamic structural stability of the thoria nanoparticles. Density functional theory (DFT) was used to calculate the defect formation energy, highlighting the feasibility of dual ion (Er3+ and Yb3+) doping in thoria. The morphology and average size of the doped thoria was studied using high resolution transmission electron microscopy (HRTEM), and any defects evolving as a result of aliovalent doping were probed using positron annihilation lifetime spectroscopy (PALS). With 980 nm laser excitation, the nanothoria emits green and near-red light. A significant enhancement of the red-to-green intensity ratio of Er3+ ions in nanothoria was observed with an increase in Yb3+ concentration which resulted in beautiful color tunability from green to yellow light in going from lower (up to ∼5 mol%) to higher (10 and 15 mol%) Yb3+ concentration. The power dependence and the dynamics of the upconverted emission confirm the existence of two-photon upconversion processes for the green and red emissions.

Oxygen vacancy-enriched Zn2SnO4 for aliphatic alcohol sensing and enhanced selectivity towards n-butanol.

The sensitive detection of toxic flammable volatile organics using low cost efficient sensors is important for ensuring both indoor and outdoor safety. It is essential for chemical sensors to exhibit a significantly stronger response to target analytes compared to equivalent amounts of analogous competing chemicals. In line with this importance, current work evaluated the performance of Zn2SnO4, a n-type semiconducting metal oxide, for sensing n-butanol in comparison to methanol, ethanol, and propanol vapours. These vapours fall within the category of aliphatic alcohols but vary in characteristics such as molecular weight, vapour pressure, volatility, and diffusivity. In this work we have explored the sensor's performance by adjusting the operating temperature over the range of 225-300 °C while detecting 1000 ppm of each of these vapours. Efforts were made to establish a correlation between the sensor's responses with the interactions of these vapours on the sensor's surface. Prior to assessing the sensing characteristics of the solid-state-route-derived Zn2SnO4, its structural characteristics, including phase purity, crystalline structure, bonding patterns, morphology, and defect characteristics, were studied. This comprehensive analysis sheds light on the potential of Zn2SnO4 as an effective sensor for detecting n-butanol.

MicroRNA397 regulates tolerance to drought and fungal infection by regulating lignin deposition in chickpea root.

Plants deposit lignin in the secondary cell wall as a common response to drought and pathogen attacks. Cell wall localised multicopper oxidase family enzymes LACCASES (LACs) catalyse the formation of monolignol radicals and facilitate lignin formation. We show an upregulation of the expression of several LAC genes and a downregulation of microRNA397 (CamiR397) in response to natural drought in chickpea roots. CamiR397 was found to target LAC4 and LAC17L out of twenty annotated LACs in chickpea. CamiR397 and its target genes are expressed in the root. Overexpression of CamiR397 reduced expression of LAC4 and LAC17L and lignin deposition in chickpea root xylem causing reduction in xylem wall thickness. Downregulation of CamiR397 activity by expressing a short tandem target mimic (STTM397) construct increased root lignin deposition in chickpea. CamiR397-overexpressing and STTM397 chickpea lines showed sensitivity and tolerance, respectively, towards natural drought. Infection with a fungal pathogen Macrophomina phaseolina, responsible for dry root rot (DRR) disease in chickpea, induced local lignin deposition and LAC gene expression. CamiR397-overexpressing and STTM397 chickpea lines showed more sensitivity and tolerance, respectively, to DRR. Our results demonstrated the regulatory role of CamiR397 in root lignification during drought and DRR in an agriculturally important crop chickpea.

Biochemical analysis of anthocyanin and proanthocyanidin and their regulation in determining chickpea flower and seed coat colour.

Flower and seed coat colour are important agronomic traits in chickpea (Cicer arietinum L.). Cultivated chickpeas are of two types namely, desi (dark seeded, purple flowered) and kabuli (light seeded, white flowered). There has been limited information about the molecular mechanism underlying colour variation of flower and seed coats in desi and kabuli chickpea. We profiled the anthocyanin and proanthocyanidin (PA) contents in chickpea flowers and seed coats. Tissue-specific silencing of two genes encoding a basic helix-loop-helix (CabHLH) protein and a tonoplast-localized multidrug and toxic compound extrusion (CaMATE1) transporter in a desi genotype resulted in the reduction in expression of anthocyanin and PA biosynthetic genes and anthocyanin and PA contents in the flower and seed coat, and produced flowers and seeds with kabuli characteristics. Transcriptional regulation of a subset of anthocyanin and PA biosynthetic genes by a natural CabHLH variant and transport assay of a natural CaMATE1 variant explained the association of these alleles with the kabuli phenotype. We carried out a detailed molecular characterization of these genes, and provided evidence that kabuli chickpea flower and seed colour phenotypes can be derived by manipulation of single genes in a desi chickpea background.

Ample Lewis Acidic Sites in Mg2B2O5 Facilitate N2 Electroreduction through Bonding-Antibonding Interactions.

Extensive research on the electrochemical nitrogen reduction reaction (NRR) has put forward a sound list of potential catalyst materials with properties inducing N2 adsorption, protonation, and reduction. However, rather than a random selection of catalysts, it is essential to understand the vitals in terms of orbital orientation and charge distribution that actually manipulate the rate-determining steps of NRR. Realizing these factors, herein we have explored a main group earth-abundant Mg-based electrocatalyst Mg2B2O5 for NRR due to the abundance of Lewis acid sites in the catalyst favoring the bonding-antibonding interactions with the N2 molecules. Positron annihilation studies indicate that the electronic charge distribution within the catalyst has shallow surface oxygen vacancies. These features in the catalyst enabled a sound Faradaic efficiency of 46.4% at -0.1 V vs reversible hydrogen electrode for the selective NH3 production in neutral electrolyte. In situ Fourier transform infrared suggests a maximum N-N bond polarization at -0.1 V and detected H-N-H and -NH2 intermediates during the course of the NRR on the catalyst surface. In a broader picture, the biocompatibility of Mg2+ diversifies the utility of this catalyst material in N2/biofuel cell applications that would certainly offer a green alternative toward our goal of a sustainable society.

Local Structure and Speciation-Driven UO22+ → Sm3+ Energy Transfer for Enhanced Luminescence in Li2B4O7.

Herein, we report the uranyl sensitization of Sm3+ emissions in uranium-codoped Li2B4O7:Sm3+ phosphor. The uranyl speciation in codoped [Sm, U] LTB samples was determined by synchrotron-based extended X-ray absorption fine structure (EXAFS) spectroscopy that revealed two coordination shells for U(VI) ions with bond distances of U-Oax (∼1.81 Å) and U-Oeq (∼2.30 Å). EXAFS fitting suggested that the uranyl moiety is present as pentagonal bipyramids (UO7) and hexagonal bipyramids (UO8) with five and six equatorial oxygen ligands, respectively. The alteration of the local structure of Sm3+ from [SmO4] to [SmO7] polyhedra and the changes in the coordination number of equatorial oxygen for uranyl were observed with different codoping concentrations of Sm3+ and uranium. Density functional theory (DFT) calculations suggested the lowering of defect formation energy for Li vacancies on codoping of Sm and U. Hence, we proposed the increase of the equatorial coordination number of UO22+ on the increase in the lithium vacancies in LTB. In addition, DFT supported the feasibility of efficient energy transfer (ET) due to the overlap of uranium and Sm3+ excited state levels. The influence of the same on the spectral features and UO22+ → Sm3+ energy transfer was investigated by time-resolved photoluminescence (PL) studies. The ET efficiency from the UO22+ to Sm3+ was 70.5% in 0.5 mol % codoped [Sm, U] LTB samples. The correlation of EXAFS and luminescence properties indicated a red shift in vibronic features of uranyl emission with increase in the equatorial coordination of the uranyl moiety from five to six. Additionally, a higher probability of ET was observed for uranyl speciation as UO8 hexagonal bipyramids. Temperature-dependent emissions and decay profiles were collected under uranyl excitation to investigate the thermal dependence of ET. A high energy barrier (Ea ∼ 4027 cm-1) was evaluated for the thermal quenching of Sm3+ emissions. This work provides insights into the modulation of luminescence and ET efficiency via structural changes in uranyl and Sm local environment in LTB phosphor.

Stabilization of Eu2+ in Li2B4O7 with the BO3 network through U6+ co-doping and defect engineering.

Owing to the unique 4f-5d transitions and the involvement of 5d electrons, the divalent europium (Eu2+) ion is extensively used as a dopant ion in luminescent materials for phosphor-converted light emitting diodes (pc-LEDs) and other technological applications. Earlier reports in most of the cases have shown that the reduction of Eu3+ to Eu2+ requires very high temperatures and large hydrogen flux. In this study, a co-doping strategy with higher valent U6+ ions was utilized to successfully stabilize Eu2+ ions in the Li2B4O7 (LTB) host with both the BO3 and BO4 network in low H2 flux of only 8%. It is postulated that charge transfer occurs from U to Eu, resulting in the reduction of the charged state of Eu and the reaction probably proceeds via the formation of paramagnetic transient [U5+-Eu3+] species in the co-doped LTB. The same is also believed to be facilitated by the enhanced formation of Li-O type vacancy clusters in co-doped samples and enhanced oxygen vacancies in a reducing atmosphere. We believe this work will pave a new pathway for stabilizing the unusual oxidation state of lanthanides and transition metal ions through co-doping with hexavalent uranium ions.

Design, synthesis, and in silico study of hybrid oxoazetidine conjugated thiazoles as anti-EGFR with cytotoxicity activity.

We report a series of hybrid oxoazetidine conjugated thiazoles as epidermal growth factor receptor (EGFR) inhibitors, which were synthesized and tested using a variety of in silico and in vitro studies. The compounds were found to be active against breast and hepatic cancer cell lines, with Compounds 7a, 7b, and 7e being the most potent ones. The derivatives were also evaluated for molecular docking and complementarity studies to explicate fundamental substituent groups essential for their bioactivity. Moreover, the structural activity relationship of the analogues was performed for future compound optimization. These studies advocated that the analogues have a high affinity towards EGFR with favorable anticancer potential. The study advised that the derivatives have potency against breast and hepatic cancer and can assist as an initial scaffold for further development of anti-EGFR compounds.

Generation and transplantation of hepatocytes-like cells using human origin hepatogenic serum for acute liver injury treatment.

Liver failure is a critical disease for which regenerative therapies are still being explored. The major limitation in the use of a clinical grade, viable cell-based therapy approach is the scarce availability of sufficient number of in-vitro differentiated hepatocyte-like cells (HLC) that can induce regeneration and ameliorate liver injury. Here, we report for the first time an approach to engineer HLCs using sera of hyperbilirubin patients that act as a reservoir of differentiation factor. Utilizing our humanized approach, mesenchymal stem cells (hMSC) derived from umbilical cord tissue were transdifferentiated into HLC using patient-derived serum along with dimethyl sulfoxide (DMSO). We studied the effects of serum on the proliferation, cell cycle analysis, and apoptosis of hMSC by various differentiation combinations. We optimized the hepatic transdifferentiation ability of hMSC with hyperbilirubin serum treatment for a period of 7 days. Assessment of HLC functionalities was shown by quantifying the HLC spent medium for albumin and urea secretions. Transplantation of HLC in an acute liver injury (ALI) rat model showed an effective improvement in the liver function and histological changes in the liver. The results of this study suggest that hMSC-derived HLC using humanized hepatogenic serum holds a promising potential for cell transplantation, as an efficient therapy modality for liver failure in humans.

Solution-processable organic light-emitting diodes utilizing electroluminescent perylene tetraester-based columnar liquid crystals.

Herein, we reveal a homologous series of liquid crystals involving perylene tetraesters as the core connected to the four trialkoxyphenyl units at the periphery using the triazole moiety as the linker. A thorough analysis using differential scanning calorimetry, polarized optical microscopy, and small- and wide-angle X-ray scattering studies confirm that all the mesogens 1a-c hold a stable enantiotropic columnar mesophase. Suitable molecular orbital levels and excellent material photophysical and thermal properties encouraged the study of their electroluminescent properties. Due to this, a well designed solution-processable organic light emitting diode device structure is configured as ITO (125 nm)/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) (35 nm)/host: x wt% emitter (x = 0.5, 1.0, 3.0, 5.0) (20 nm)/2,2'2''-(1,3,5-benzinetriyl)tris(1-phenyl-1-H-benzimidazole) (TPBi) (40 nm)/lithium fluoride (LiF) (1 nm)/aluminium (Al) (200 nm) using compounds 1a-c as emitters. 4,4',4''-Tris[phenyl(m-tolyl)amino]triphenylamine (m-MTDATA) and 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP) were chosen as two different host materials. The current density-voltage-luminance and current efficacy-luminance-power efficacy plots suggest that m-MTDATA is a better host than CBP. Amongst, device based on 1 wt% emitter 1c doped in the m-MTDATA host matrix displayed the best performance, with a maximum power efficacy of 17.2 lm W-1, current efficacy of 18.5 cd A-1, and external quantum efficiency of 6.3%.

Correction: Luminescent columnar discotics as highly efficient emitters in pure deep-blue OLEDs with an external quantum efficiency of 4.7.

Correction for 'Luminescent columnar discotics as highly efficient emitters in pure deep-blue OLEDs with an external quantum efficiency of 4.7%' by Joydip De et al., Soft Matter, 2022, DOI: 10.1039/d1sm01558c.

Luminescent columnar discotics as highly efficient emitters in pure deep-blue OLEDs with an external quantum efficiency of 4.7.

Development of materials that serve as efficient blue emitters in solution-processable OLEDs is challenging. In this study, we report three derivatives of C3-symmetric 1,3,5-tris(thien-2-yl)benzene-based highly luminescent room temperature columnar discotic liquid crystals (DLCs) suitable as solid-state emitters in OLED devices. When employed in solution-processed OLEDs, one of the derivatives having the highest photoluminescence quantum yield exhibited a maximum EQE of 4.7% and CIE chromaticity of (0.16, 0.05) corresponding to the ultra deep-blue emission. The finding is sufficiently significant in the field of DLC-based deep blue emitters.

Design of need-based phosphors and scintillators by compositional modulation in the ZnGa2-xAlxO4:Cr3+ spinel: pure compound versus solid solutions.

Materials that can depict persistent deep red light under both ultraviolet (UV) and X-ray illumination can be a boon to sustainable economy, particularly for optical imaging, solid state lighting, and anticounterfeiting applications. Herein, we have made a series of compounds starting from ZnGa2O4:Cr3+ to ZnAl2O4:Cr3+ (individual spinel) by substituting the varied concentration of Al3+ in place of Ga3+ in ZnGa2-xAlxO4:Cr3+ (solid solution). By virtue of the structural and defect engineering doping strategy, the photo and radioluminescence are expected to be improved. Both Cr and Al doping was found to be energetically favorable in ZnGa2O4, where the same does not hold true for Ga doping in ZnAl2O4, as indicated by the DFT-calculated defect formation energies. There seems to be ordering around the dopant ion in the solid solutions compared to either ZnGa2O4 or ZnAl2O4 and is also reflected to as lower persistent luminescence (PerL) lifetimes. PerL under UV, in general. was found to be lower with the enhancement in the Al3+ content endowed by the formation of Cr-Cr ion pair, lower probability of antisite formation, and widening band gap. On the other hand, X-ray excited emission enhances in the solid solution due to the decrease in cation inversion and associated defects. Confocal Microscopy showed that larger particles depicted much brighter deep red emission but failed to percolate to the human cells to a detectable limit; hence, future work is needed for the functionalization of the ZnGa2-xAlxO4:Cr3+ spinel. This work could be of great implication in designing need-based materials, where UV and X-ray excitation is required, for deep red emission with persistent characteristics from chromium-doped spinels.

Molten-Salt-Assisted Annealing for Making Colloidal ZnGa2 O4 :Cr Nanocrystals with High Persistent Luminescence.

Persistent luminescent nanocrystals (PLNCs) in the sub-10 nm domain are considered to be the most fascinating inventions in lighting technology owing to their excellent performance in anti-counterfeiting, luminous paints, bioimaging, security applications, etc. Further improvement of persistent luminescence (PersL) intensity and lifetime is needed to achieve the desired success of PLNCs while keeping the uniform sub-10 nm size. In this work, the concept of molten salt confinement to thermally anneal as-synthesized ZnGa2 O4 :Cr3+ (ZGOC) colloidal NCs (CNCs) in a molten salt medium at 650 °C is introduced. This method led to significantly monodispersed and few agglomerated NCs with a much improved photoluminescence (PL) and PersL intensity without much growth in the size of the pristine CNCs. Other strategies such as i) thermal annealing, ii) overcoating, and iii) the core-shell strategy have also been tried to improve PL and PersL but did not improve them simultaneously. Moreover, directly annealing the CNCs in air without the assistance of molten salt could significantly improve both PL and PersL but led to particle heterogeneity and aggregation, which are highly unsuitable for in vivo imaging. We believe this work provides a novel strategy to design PLNCs with high PL intensity and long PersL duration without losing their nanostructural characteristics, water dispersibility and biocompatibility.