We demonstrate first room temperature, and ultrabright single photon emission from a color center in two-dimensional multilayer hexagonal boron nitride. Density Functional Theory calculations indicate that vacancy-related centers are a likely source of the emission.

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Quantum emission from hexagonal boron nitride monolayers

The surface-modified nanomaterials are considered effective drug carriers due to their high electronic sensitivity and reactivity towards various drug molecules. In this work, we have modified B12N12 nanocage by doping metal atoms (Al and Ga) to form AlB11N12 and GaB11N12 nanocages, and deeply scrutinized the interactions of these nanocages towards emodin (ED) drug via DFT calculations. Our calculations demonstrated that AlB11N12 and GaB11N12 show high sensitivity and reactivity towards the ED than B12N12 in both gas and solvent media. ED interacts with AlB11N12 and GaB11N12 in gas media with energies −46.69 and −51.29 kcal/mol and in solvent media with −57.50 and −47.05 kcal/mol whereas the interaction energies of ED/B12N12 system are found about −22.48 and −24.68 kcal/mol in gas and water media respectively. The adsorption process significantly effects on the HOMO and LUMO levels which leads to reduction of Eg of ED/AlB11N12 and ED/GaB11N12 approximately 42.48% and 52.03%. Thus, the electrical conductivity greatly enhanced due to the reduction of Eg which can produce electrical signal. This phenomenon implies that AlB11N12 and GaB11N12 could be used as promising electronic drug sensor for ED. Furthermore, QTAIM and RDG analysis also indicate the strong hydrogen-bonded interaction between ED and both AlB11N12, and GaB11N12.

Theoretical investigation of emodin conjugated doped B12N12 nanocage by means of DFT, QTAIM and PCM analysis

The surface-modified nanomaterials are considered effective drug carriers due to their high electronic sensitivity and reactivity towards various drug molecules. In this work, we have modified B12N12 nanocage by doping metal atoms (Al and Ga) to form AlB11N12 and GaB11N12 nanocages, and deeply scrutinized the interactions of these nanocages towards emodin (ED) drug via DFT calculations. Our calculations demonstrated that AlB11N12 and GaB11N12 show high sensitivity and reactivity towards the ED than B12N12 in both gas and solvent media. ED interacts with AlB11N12 and GaB11N12 in gas media with energies −46.69 and −51.29 kcal/mol and in solvent media with −57.50 and −47.05 kcal/mol whereas the interaction energies of ED/B12N12 system are found about −22.48 and −24.68 kcal/mol in gas and water media respectively. The adsorption process significantly effects on the HOMO and LUMO levels which leads to reduction of Eg of ED/AlB11N12 and ED/GaB11N12 approximately 42.48% and 52.03%. Thus, the electrical conductivity greatly enhanced due to the reduction of Eg which can produce electrical signal. This phenomenon implies that AlB11N12 and GaB11N12 could be used as promising electronic drug sensor for ED. Furthermore, QTAIM and RDG analysis also indicate the strong hydrogen-bonded interaction between ED and both AlB11N12, and GaB11N12. 

After the successful synthesis of graphene/hexagonal boron nitride (h-BN) heterostructures, research works have been carried out for their plausible real-world device applications. Such 2D nanosheets gain great attention as they have shown promising gas sensing properties due to their high surface-to-volume ratio and unique electronic properties between graphene and h-BN. Herein, we report a first-principles density functional theory investigation of the structural and electronic properties of pristine graphene (PG), pristine BN, and their in-plane heterostructures employing B3LYP and dispersion-corrected van der Waals functional WB97XD with the 6-311G (d, p) basis set. We found that these predicted nanosheets show good structural stability with favorable cohesive energy and the bandgap gradually increases with the increase in the B–N concentration. We have also studied their adsorption properties toward toxic gas molecules (SO2 and CO). Among these heterostructures, G2BN2 exhibits greater adsorption energy of about −0.237 eV and −0.335 eV when exposed to SO2 and CO gas molecules, respectively. The electronic properties such as HOMO and LUMO energies, HOMO–LUMO energy gap, Fermi level, work function, and conductivity significantly changed after the adsorption of SO2 gas on the nanosheets except for PG, whereas these parameters remain almost the same after the adsorption of the CO gas molecule. Mulliken and natural bond orbital (NBO) charge analysis reveals that charge transfer occurs from gas molecules to the nanosheets except when SO2 is adsorbed onto PG. Although the adsorption energies for CO gas are slightly greater than those for SO2 gas for these nanosheets, all other investigations such as electronic properties, charge transfer analysis, molecular electrostatic potential (MEP) map, and global indices predict that these nanosheets are good sensors for SO2 gas than CO gas molecules.

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In-plane graphene/boron nitride heterostructures and their potential application as toxic gas sensors

The growth, structure, and properties of two-dimensional boron nitride (BN) nanostructures synthesized by a thermal chemical vapor deposition method have been systematically investigated. Most of the BN nanosheets (BNNSs) were less than 5 nm in thickness, and their purity was confirmed by X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, electron energy loss spectroscopy, and Raman spectroscopy. The effects of the process variables on the morphology and roughness of the coatings were studied using atomic force microscopy and scanning electron microscopy. A smooth BN coating was obtained at 900 degrees C, while compact BNNS coatings composed of partially vertically aligned nanosheets could be achieved at 1000 degrees C and higher temperatures. These nanosheets were mostly separated and exhibited high surface area especially at higher synthesis temperatures. The nonwetting properties of the BNNS coatings were independent of the water pH and were examined by contact angle goniometry. The present results enable a convenient growth of pure BNNS coatings with controllable levels of water repellency, ranging from partial hydrophilicity to superhydrophobicity with contact angles exceeding 150 degrees .

Boron nitride nanosheet coatings with controllable water repellency

Adsorption behavior of cisplatin anticancer drug on the pristine, Al- and Ga-doped BN nanosheets: A comparative DFT study

To minimize the side effects of chemotherapeutic drugs and enhance the effectiveness of cancer treatment, it is necessary to find a suitable drug delivery carrier for anticancer drugs. Recently nanomaterials are extensively being studied as drug vehicles and transport drugs in tumor cells. Using DFT calculations, the adsorption behavior with electronic sensitivity and reactivity of pristine and doped (Al, Ga and In)-BNNS towards the nitrosourea (NU) drug has been investigated in gas as well as water media. Our calculations showed that the NU drug is physically adsorbed on the pristine BNNS with −0.49 and −0.26 eV by transferring little amount of charge of about 0.033e and 0.046e in gas and water media in the most stable complex. But after replacing one of the central B atoms with an Al or Ga or In atom, the sensitivity of the doped BNNS remarkably enhances towards the NU drug molecules. The NU drug prefers to be chemically adsorbed on the BN(Al)NS, BN(Ga)NS and BN(In)NS by −1.28, −1.58 and −3.06 eV in the gas phase and −1.34, −1.23 and −3.65 eV in water media in the most stable complexes respectively. The large destabilization of LUMO energies after the adsorption of the NU drug on the BN(Al)NS, BN(Ga)NS and BN(In)NS significantly reduces their Eg from 4.37 to 0.69, 4.37 to 1.04 and 4.33 to 0.66 eV in the S1 complex respectively. The reduction of Eg of doped BNNS by the NU drug greatly enhances the electrical conductivity which can be converted to an electrical signal. Therefore, this doped BNNS can be used as a fascinating electronic sensor for the detection of NU drug molecules. Furthermore the work function of the doped BNNS was largely affected by the NU drug adsorption about 47.3%, 39.3% and 40.4% in the gas phase and 41.3%, 36.6% and 31.6% in water media in the S1 complex of NU/BN(Al)NS, NU/BN(Ga)NS and NU/BN(In)NS respectively. Thus, the doped BNNS may be used as a Ф type sensor for NU drug molecules.

Surface adsorption of nitrosourea on pristine and doped (Al, Ga and In) boron nitride nanosheets as anticancer drug carriers: the DFT and COSMO insights

The DFT study on the adsorption behaviour of the C24, B12N12, and Al12N12 nanocages and their heteronanocages towards the anticancer drug cisplatin (CP) was performed in gas and water media. Among the three pristine nanocages, Al12N12 exhibited high adsorption energy ranging from −1.98 to −1.63 eV in the gas phase and −1.47 to −1.39 eV in water media. However, their heterostructures C12–Al6N6 and B6N6–Al6N6 showed higher interaction energies (−2.22 eV and −2.14 eV for C12–Al6N6 and B6N6–Al6N6) with a significant amount of charge transfer. Noteworthy variations in electronic properties were confirmed by FMO analysis and DOS spectra analysis after the adsorption of the cisplatin drug on B12N12 and B6N6–Al6N6 nanocages. Furthermore, an analysis of quantum molecular descriptors unveiled salient decrement in global hardness and increments in electrophilicity index and global softness occurred after the adsorption of CP on B12N12 and B6N6–Al6N6. On the other hand, the above-mentioned fluctuations are not so noteworthy in the case of the adsorption of CP on Al12N12, C12–B6N6, and C12–Al6N6. Concededly, energy calculation, FMO analysis, ESP map, DOS spectra, quantum molecular descriptors, dipole moment, COSMO surface analysis, QTAIM analysis, and work function analysis predict that B12N12 and B6N6–Al6N6 nanocages exhibit high sensitivity towards CP drug molecules.

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Exploring the adsorption ability with sensitivity and reactivity of C12–B6N6, C12–Al6N6, and B6N6–Al6N6 heteronanocages towards the cisplatin drug: a DFT, AIM, and COSMO analysis

Inspired by the recently synthesized hexagonal boron nitride (h-BN) doped graphene, density functional theory (DFT) calculations were performed to evaluate the anodic properties of BN doped graphene (BN-G), graphene oxide (BN-GO) and reduced graphene oxide (BN-rGO) for Li/Na ion batteries (LIBs/NIBs). Our proposed materials show a semiconducting character with band gaps of 1.4, 0.67 and 0.45 eV for BN-G, BN-GO and BN-rGO, respectively. Among the three nanosheets, BN-rGO shows strong interaction behavior with Li/Na whereby the defected site exhibits high reactivity compared to the other adsorption sites. The adsorption energies are found to be about -4.72/-4.10 eV for Li/Na at the defected site, which are consecutively 3 and 2 times stronger than the adsorption energies of BN-G and BN-GO. It is predicted by partial density of states (PDOS) and band structure analysis that the nanosheets will exhibit metallic behavior through the adsorption process. Relatively low diffusion barriers are found to be about 0.47 and 0.22 eV when Li and Na moved from one adsorption site to another nearby adsorption site on BN-rGO. Among them, BN-rGO shows a high specific capacity, about 1583 and 1319 mA h g-1 for LIBs and NIBs. Therefore, the suitable adsorption energy with metallic behavior of the nanosheet combined with the high specific capacity confirm that BN-rGO is a promising anode candidate for Li/Na ion batteries.

Tuning the electrochemical behavior of graphene oxide and reduced graphene oxide via doping hexagonal BN for high capacity negative electrodes for Li and Na ion batteries.

Afiya Akter Piya

Papers

Adsorption behavior of cisplatin anticancer drug on the pristine, Al- and Ga-doped BN nanosheets: A comparative DFT study

Surface adsorption of nitrosourea on pristine and doped (Al, Ga and In) boron nitride nanosheets as anticancer drug carriers: the DFT and COSMO insights

Exploring the adsorption ability with sensitivity and reactivity of C12–B6N6, C12–Al6N6, and B6N6–Al6N6 heteronanocages towards the cisplatin drug: a DFT, AIM, and COSMO analysis

Tuning the electrochemical behavior of graphene oxide and reduced graphene oxide via doping hexagonal BN for high capacity negative electrodes for Li and Na ion batteries.

Exploring the adsorption performance of doped graphene quantum dots as anticancer drug carriers for cisplatin by DFT, PCM, and COSMO approaches