All-Inorganic Lead-Free Doped-Metal Halides for Bright Solid-State Emission from Primary Colors to White Light.

Metal halides have been explored with the aid of strong photoluminescence for optical and optoelectronic applications. However, the preparation of lead (Pb)-free solid-state emitters with high photoluminescence quantum yields (PLQYs) and tunable emission remains exceptionally challenging. Herein, we report metal ion (Cu(I), Mn(II), and Sn(II))-doped Cs3ZnI5 single crystals that are primary color (violet, green, and orange/red) emitters with extremely high PLQYs. Whereas the Mn-doping leads to bright green emissions with 100% PLQY, the Cu- and Sn-doping give rise to blue and red emissions with PLQYs of 57 and 64%, respectively. Interestingly, higher Mn doping results in white light emissive crystals as a side product, which are found to be Mn-doped CsI single crystals. The bright white light emissive crystals can be synthesized in a pure form in large quantities and exhibit a high color rendering index (CRI) of 78 and CIE coordinates of (0.30, 0.38), which are close to daylight conditions. To the best of our knowledge, this is the first demonstration of white light emission from a complete inorganic system. Importantly, the single crystals of all colors exhibit high long-term stability as their PLQY remains unchanged even after 2 months of preparation, and are thermally stable up to 600 °C.

Lead-Free, Water-Stable A3 Bi2 I9 Perovskites: Crystal Growth and Blue-Emitting Quantum Dots [A=CH3 NH3 + , Cs+ , and (Rb0.05 Cs2.95 )+ ].

Despite the great success in the increase in the power conversion efficiency of lead halide perovskite solar cells, the toxicity of lead and the unstable nature of the materials are still major concerns for their wider implementation at the industrial level. Herein, large-size single crystals (SCs) are developed in HI solution by using a temperature lowering method and nanocrystals (NCs) of A3 Bi2 I9 perovskites [where A=CH3 NH3 + (MA)+ , Cs+ , and (Rb0.05 Cs2.95 )+ ] are formed in ethanol (EtOH) and toluene (TOL). The stability of A3 Bi2 I9 perovskite is investigated by immersing the SCs for 24 h and pellets for 12 h in water. Moreover, the A3 Bi2 I9 perovskite NCs displays a promising photoluminescence quantum yield of 17.63 % and a long lifetime of 8.20 ns.

MA2CoBr4: lead-free cobalt-based perovskite for electrochemical conversion of water to oxygen.

We have synthesized a lead-free stable organic-inorganic perovskite (MA2CoBr4) by using non-hazardous solvents such as methanol and ethanol, which are eco-friendly and safe to handle in comparison to DMF, toluene, etc. Single crystals of MA2CoBr4 were grown using a simple solution technique, and their electrochemical oxygen evolution was investigated in a wide pH range.

Solvent-Assisted Tuning of the Size and Shape of CsPbBr3 Nanocrystals via Redispersion Process at Ambient Condition.

All-inorganic CsPbBr3 perovskite nanocrystals are emerging as a new class of semiconductors with outstanding optoelectronic properties and great potential for various applications, such as, lasing, photon detection, photovoltaics, etc. This article provides the effect of solvents on the reprecipitation of CsPbBr3 perovskite at room temperature. The results observed for CsPbBr3 perovskite in various antisolvents showed various cubes (nano- to microsized), self-assembly of nanocubes and nanorods. In addition, all of the various sizes (nano to micro) of cubes and self-assembly of nanocubes and shape-controlled nanorods exhibited band gap tuning at the green light region. The corresponding microscopy (field emission scanning electron microscopy and high-resolution transmission electron microscopy) images and photoluminescence quantum yield as well as lifetime decay are presented. To the best of our literature knowledge, this is the first report on various solvent-assisted studies on CsPbBr3 perovskite nanocrystals.

Novel substituted hydrazono indolo[2,1-b]quinazoline-6,12-dione analogues as cytostatic agents: Synthesis, crystal structure, biological evaluation and molecular docking studies.

A series of novel substituted hydrazono indolo[2,1-b]quinazoline-6,12-dione analogues have been synthesized and screened for their in vitro cytotoxic and antimicrobial activities. Among all the target compounds, 3c exhibited the most potent inhibitory activity against three cancer cell lines MCF-7, A549, HeLa with IC50 values 07.14±1.285µM, 09.18±0.968µM and 10.57±0.581µM respectively, while maintaining low toxicity towards non-cancer originated cell line, HEK-293. The detailed studies about molecular interactions with probable target protein indoleamine 2,3-dioxygenase (IDO1) were done by using docking simulations. The results from docking models are in consistent with the experimental in vitro cytotoxic activity conclusions i.e. 3c shows the highest binding energy -11.25kcal/mol. Furthermore, antimicrobial studies revealed that the compound 3e has shown excellent anti bacterial activity against four tested strains and the compounds 3b, 3e and 3f have shown good anti fungal activity against two tested organisms as compared with their standard drugs.

Development of selective DprE1 inhibitors: Design, synthesis, crystal structure and antitubercular activity of benzothiazolylpyrimidine-5-carboxamides.

Decaprenylphosphoryl-b-D-ribose 20-epimerase (DprE1) is a potential drug target for development of antitubercular agents. Structure based drug discovery approach yielded twenty novel derivatives of benzothiazolylpyrimidine-5-carboxamides (7a-t) which were synthesised by three component one pot reaction involving benzothiazolyl oxobutanamide, thiourea and substituted aromatic benzaldehydes. These derivatives were evaluated for antitubercular activity to determine MIC and compound 7a, 7e, 7f and 7o were found to be potentially active against Mycobacterium tuberculosis (H37Rv). Log P of these compounds was found to be between 2.0 and 3.0 making them suitable for oral dosing. DprE1 selectivity and pharmacokinetic studies were carried out for these compounds of which 7a and 7o were found to be highly selective and bioavailability was found to be above 52% by oral dose. Crystal structure of 7a was studied and molecular packing was determined, it exhibited a triclinic crystal lattice arrangement having hydrogen bonded dimeric arrangement. Drug receptor interactions were studied which exhibited docking in the active site of receptor with hydrogen bonding, hydrophobic interactions, vdW interactions with amino acid residues such as Cys387, Asn385, Lys418, Tyr314, Gln334 and Lys367 respectively. 3D QSAR analysis was carried out by kNN-MFA method to determine and develop theoretical model, best suitable model was found to be based on Simulated Annealing k-Neariest Neighbour Molecular Field Analysis (SA kNN-MFA). The model provided with hydrophobic descriptors in positive side indicating the need of bulky groups, steric and electronegative descriptors in negative coordinates hints with contribution by the electronegative substitutions as favourable and desirable moieties for enhancing the activity. The q(2), q(2)_se and Pred_r(2)se were found to be 0.5000, 0.6404 and 1.0094 respectively. A pharmacophore model was generated which suggested for necessity of aromatic, aliphatic carbon centre and hydrogen bond donor for development of newer DprE1 selective inhibitors.