A Multifunctional Dye Molecule as the Interfacial Layer for Perovskite Solar Cells.

In perovskite solar cells (PSCs), defects in the interface and mismatched energy levels can damage the device performance. Improving the interface quality is an effective way to achieve efficient and stable PSCs. In this work, a multifunctional dye molecule, named ThPCyAc, was designed and synthesized to be introduced in the perovskite/HTM interface. On one hand, various functional groups on the acceptor unit can act as Lewis base to reduce defect density and suppress nonradiative combinations. On the other hand, the stepwise energy-level alignment caused by ThPCyAc decreases the accumulation of interface carriers for facilitating charge extraction and transmission. Therefore, based on the ThPCyAc molecule, the devices exhibit elevated open-circuit voltage and fill factor, resulting in the best power conversion efficiency (PCE) of 23.16%, outperforming the control sample lacking the interface layer (PCE = 21.49%). Excitingly, when attempting to apply it as a self-assembled layer in inverted devices, ThPCyAc still exhibits attractive behavior. It is worth noting that these results indicate that dye molecules have great potential in developing multifunctional interface materials to obtain higher-performance PSCs.

Extending the π-Conjugated System in Spiro-Type Hole Transport Material Enhances the Efficiency and Stability of Perovskite Solar Modules.

Hole transport materials (HTMs) are a key component of perovskite solar cells (PSCs). The small molecular 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl)-amine-9,9'-spirobifluorene (spiro-OMeTAD, termed "Spiro") is the most successful HTM used in PSCs, but its versatility is imperfect. To improve its performance, we developed a novel spiro-type HTM (termed "DP") by substituting four anisole units on Spiro with 4-methoxybiphenyl moieties. By extending the π-conjugation of Spiro in this way, the HOMO level of the HTM matches well with the perovskite valence band, enhancing hole mobility and increasing the glass transition temperature. DP-based PSC achieves high power conversion efficiencies (PCEs) of 25.24 % for small-area (0.06 cm2 ) devices and 21.86 % for modules (designated area of 27.56 cm2 ), along with the certified efficiency of 21.78 % on a designated area of 27.86 cm2 . The encapsulated DP-based devices maintain 95.1 % of the initial performance under ISOS-L-1 conditions after 2560 hours and 87 % at the ISOS-L-3 conditions over 600 hours.

A N-Ethylcarbazole-Terminated Spiro-Type Hole-Transporting Material for Efficient and Stable Perovskite Solar Cells.

The development of stable and efficient hole-transporting materials (HTMs) is critical for the commercialization of perovskite solar cells (PSCs). Herein, a novel spiro-type HTM was designed and synthesized where N-ethylcarbazole-terminated groups fully substituted the methoxy group of spiro-OMeTAD, named spiro-carbazole. The developed molecule exhibited a lower highest occupied molecular orbital level, higher hole mobility, and extremely high glass transition temperature (Tg =196 °C) compared with spiro-OMeTAD. PSCs with the developed molecule exhibited a champion power conversion efficiency (PCE) of 22.01 %, which surpassed traditional spiro-OMeTAD (21.12 %). Importantly, the spiro-carbazole-based device had dramatically better thermal, humid, and long-term stability than spiro-OMeTAD.

Tetraphenylethylene-Arylamine Derivatives as Hole Transporting Materials for Perovskite Solar Cells.

A series of hole transporting materials (HTMs) with fused tetraphenylethylene cores (9,9'-bifluorenylidene and dibenzo[g,p]chrysene) as well as different substitution positions of arylamine side arms has been designed and synthesized. A reference HTM with a non-fused tetraphenylethylene core is also prepared for a comparative study. It is noted that fused tetraphenylethylene molecules show a bathochromic spectral shift, electronegative character, and lower reorganization energies than the non-fused ones. Furthermore, the molecules with side arms located on the meta-position on the tetraphenylethylene core in terms of a double bond exhibit a deeper highest occupied molecular orbital level than those of the para-position-based ones whether tetraphenylethylene is fused or not. Moreover, the reorganization energies of fused meta-position-based HTMs are lower than those of para-position-based HTMs. Fused tetraphenylethylene HTMs own a better hole-extraction capability than the non-fused ones. When used in perovskite solar cells, all devices with fused tetraphenylethylene HTMs display better performance than those of the non-fused ones. The HTMs based on dibenzo[g,p]chrysene exhibit better performance than those of bifluorenylidene. Moreover, the devices with HTMs with side arms located on the meta-position on the tetraphenylethylene core display higher power conversion efficiency than those of the para-position-based ones. The results give some new insight and reference to develop ideal HTMs for perovskite solar cells.

A computational study on the interactions between a layered imine-based COF structure and selected anticancer drugs.

The covalent organic frameworks (COFs) are important materials in drug delivery. Herein, the interactions between an imine-based COF with selected commercially available anticancer drugs are studied. Molecular dynamics (MD) simulation studies were used. The studies were carried out in four different temperatures to find out the impact of the temperature on the binding free energies between the drugs and COF structure. It was found that the effect of temperature on binding free energy is ignorable. Between the hydrogen bonding, electrostatic, and van der Waals interactions, the last one is the most important one to keep the drug and COF next to each other. Also, the van der Waals interaction is keeping the layers of COF next to each other to create cavities. The cavities can be loaded with different drugs and the system can be used in drug delivery systems. Based on the obtained results, the drugs that are more lipophilic prefer to adhere more strongly to the COF in comparison with hydrophilic drugs.

Introducing ammonium salt into hole transporting materials for perovskite solar cells.

The developed ammonium salt-containing hole transporting material could passivate perovskite defects and transport holes, and exhibits better performance compared with the non-ammonium salt counterpart.

Fused tetraphenylethylene-triphenylamine as an efficient hole transporting material in perovskite solar cells.

A fused tetraphenylethylene-based hole transporting material shows higher power conversion efficiency and better stability compared with its non-fused counterpart, and the former molecule even outperforms the conventional spiro-OMeTAD.

Two-dimensional triphenylene cored hole-transporting materials for efficient perovskite solar cells.

Two organic hole-transporting materials comprising a two-dimensional triphenylene core and methoxyl-arylamine terminal units are developed and applied in perovskite solar cells. Enhanced photovoltaic and stability performance are obtained using TPH-T compared with those of spiro-OMeTAD.

A Computational Study on the Blocking Ability of Selected Commercially Available Anticancer Drugs and Their Hypothetic Derivatives on the CCR5.

Computational studies were done on the complexes between some commercially available anticancer drugs and their hypothetic derivatives and the CCR5 protein. At first step, the docking studies were done to obtain the best ligand that can inhibit the CCR5 protein. Based on the binding energy results obtained from the docking studies, 16 complexes were selected. Molecular dynamic studies were carried out on these structures and then molecular mechanics-generalized Born surface area calculations were done to find the binding energies of the ligands to the CCR5 protein. Based on the investigation of the binding modes of the ligands to the CCR5 protein, the TYR and ALA have more tendency to bind to the ligand moieties. By decomposing of the binding energies, it was found that the van der Waals interactions have the most important role in the binding of ligands to the protein in comparison with the electrostatic and hydrogen bonding interactions. The results of the interaction potential surface map analysis showed that the nitrogen and oxygen atoms have a relatively similar role in the binding of ligands to the CCR5 protein structure.

The inhibitory effect of farnesiferol C against catalase; Kinetics, interaction mechanism and molecular docking simulation.

Farnesiferol C (FC) is a natural sesquiterpene coumarin, which includes a widely range of biological activities. In this work, effects of FC on the structure and catalytic function of bovine liver catalase (BLC) was assessed by various spectroscopic and theoretical methods. Kinetic studies showed that FC has a remarkable inhibitory activity on BLC via mixed-type inhibition. The IC50 value as the inhibitory strength of FC was evaluated 1.5µM. Fluorescence spectroscopy, synchronous fluorescence, CD spectroscopy and UV-vis absorption studies revealed conformational changes in the tertiary and secondary structure of BLC as well as the position of the heme group in the presence of different concentrations of FC. Fluorescence studies revealed that FC quenches intrinsic emission of catalase via static quenching process. The binding constants at 298 and 310K were calculated 1.17×105M-1 and 1.0×105M-1, respectively. Thermodynamic data suggested that hydrophobic interactions play a major role in the binding reaction of FC on BLC. Structural studies indicated that the binding FC to the enzyme is responsible for the changes of the percentage of secondary structures' elements especially α-helix. From the simulation data, the role of Arg353 residue in the mechanism of catalase inhibition has been recognized.

Anthracene-arylamine hole transporting materials for perovskite solar cells.

Two arylamine-based hole transporting materials with an anthracene π-linker have been synthesized and tested for perovskite solar cells. Improved power conversion efficiency and stability were achieved by employing A102 compared with that of spiro-OMeTAD.

Destructive effect of non-enzymatic glycation on catalase and remediation via curcumin.

Non-enzymatic glycation of proteins is a post-translational modification that is produced by a covalent binding between reducing sugars and amino groups of lysine and arginine residues. In this paper the effect of pathological conditions, derived from hyperglycemia on bovine liver catalase (BLC) as a model protein was considered by measuring enzyme activity, reactive oxygen species (ROS) generation, and changes in catalase conformational properties. We observed that in the presence of glucose, the catalase activity gradually decreased. ROS generation was also involved in the glycation process. Thus, decreased BLC activity was partly considered as a result of ROS generation through glycation. However, in the presence of curcumin the amount of ROS was reduced resulting in increased activity of the glycated catalase. The effect of high glucose level and the potential inhibitory effect of curcumin on aggregation and structural changes of catalase were also investigated. Molecular dynamic simulations also showed that interaction of catalase with curcumin resulted in changes in accessible surface area (ASA) and pKa, two effective parameters of glycation, in potential glycation lysine residues. Thus, the decrease in ASA and increase in pKa of important lysine residues were considered as predominant factors in decreased glycation of BLC by curcumin.

A computational study on the usability of amino acid-functionalised nitrogen-doped graphene oxides as temperature-responsive drug delivery systems.

The usability of amino acid-functionalised nitrogen-doped graphene oxide (GO) structures (AA-NGO) in drug delivery (DD) systems was studied using the computational approaches. Docking, molecular dynamic (MD) and molecular mechanics generalised born surface area studies were carried out. The calculations were done at 37 and 42 °C to study the usability of the mentioned structures in thermally induced DD systems. In this method, the drug is released by increasing the temperature. For the representative cases, studies at 32, 37, 42 and 47 °C were carried out, as well. Both one-to-one and two-to-one ratio between the AA-NGO and Taxol were studied. In the one-to-one system the Lys-NGO is the best structure to be used in the thermo-sensitive DD systems, based on the binding energy differences calculated at mentioned four temperatures. In the two-to-one systems, the Glu-NGO is leading to the most promising results. In this case, the longer distance between the two layers at higher temperature was regarded as the reason for the better release of the drug at a higher temperature. In this case, at a lower temperature, the Taxol is trapped between two layers of Glu-NGO and has interactions with both of them. At higher temperature, the interaction with just one of the layers is observable, which means lesser interactions and better release of the Taxol.

Nitrogen doped nanographene structures; study on the adsorption of nucleobases, nucleotides, and their triphosphate derivatives using mixed docking, MD, and QM/MM approaches.

The interactions of the nucleobases, nucleotides, and their triphosphate derivatives in both neutral and anionic forms with the nitrogen doped graphenes (NG) were studied using docking and molecular dynamic simulation methods. In docking studies, based on binding energy results, the anionic species and nucleobases were showing the most and the least tendency toward the surface of the NG, respectively. The molecular mechanic/Poisson-Boltzmann surface area results revealed similar results, except for the anionic species; in these studies, the anionic species showed a lesser affinity toward the NG. The time-dependent density functional theory studies were carried out to investigate the effects of the NG on the electronic nature of the investigated ligands; a red-shift in all of the cases was observed. The results of binding energy decomposition and atoms in molecules studies showed that the interactions are van der Waals in nature. The graphitic, pyridinic, and pyrrolic nitrogen atoms which were considered in this study behaved similar to each other.

Studies to reveal the nature of interactions between catalase and curcumin using computational methods and optical techniques.

Curcumin is an important antioxidant compound, and is widely reported as an effective component for reducing complications of many diseases. However, the detailed mechanisms of its activity remain poorly understood. We found that curcumin can significantly increase catalase activity of BLC (bovine liver catalase). The mechanism of curcumin action was investigated using a computational method. We suggested that curcumin may activate BLC by modifying the bottleneck of its narrow channel. The molecular dynamic simulation data showed that placing curcumin on the structure of enzyme can increase the size of the bottleneck in the narrow channel of BLC, and readily allow the access of substrate to the active site. Because of the increase of the distance between amino acids of the bottleneck in the presence of curcumin, the entrance space of substrate increased from 250Å3 to 440Å3. In addition, the increase in emission of intrinsic fluorescence of BLC in presence of curcumin demonstrated changes in tertiary structure of catalase, and possibility of less quenching. We also used circular dichroism (CD) spectropolarimetry to determine how curcumin may alter the enzyme secondary structure. Catalase spectra in the presence of various concentrations of curcumin showed an increase in the amount of α-helix content.

A study on the interactions of amino acids with nitrogen doped graphene; docking, MD simulation, and QM/MM studies.

The binding properties of twenty amino acids with nitrogen-doped graphene structures were studied using docking, MD simulation, and QM/MM methods. TDDFT studies were carried out to investigate the change in the electronic properties of the amino acids because of the presence of the solvent and nitrogen-doped graphene. The results revealed that π-π interactions between the amino acids with a benzene moiety and the surface of the graphene are the most important interactions. The observed red shifts in the TDDFT results which were related to the lower LUMO energies and higher HOMO energies are consistent with this statement.

Evaluation of the effect of the chiral centers of Taxol on binding to ß-tubulin: A docking and molecular dynamics simulation study.

Taxol is one of the most important anti-cancer drugs. The interaction between different variants of Taxol, by altering one of its chiral centers at a time, with ß-tubulin protein has been investigated. To achieve such goal, docking and molecular dynamics (MD) simulation studies have been performed. In docking studies, the preferred conformers have been selected to further study by MD method based on the binding energies reported by the AutoDock program. The best result of docking study which shows the highest affinity between ligand and protein has been used as the starting point of the MD simulations. All of the complexes have shown acceptable stability during the simulation process, based on the RMSDs of the backbone of the protein structure. Finally, MM-GBSA calculations have been carried out to select the best ligand, considering the binding energy criteria. The results predict that two of the structures have better affinity toward the mentioned protein, in comparison with Taxol. Three of the structures have affinity similar to that of the Taxol toward the ß-tubulin.

A facile three- and four-component procedure toward the synthesis of functionalized pyrano- and benzo[f]quinoxaline derivatives.

A two-step procedure has been used to synthesize quinoxaline derivatives in the presence of a catalytic amount of triethylamine. Products can be separated from the reaction media by simple filtration. When EtOH was used as a solvent, the reaction proceeded via a three-component pathway, but in the presence of MeOH (as a solvent or in a 1-equivalent) the reaction proceeded via a four-component pathway.

A density functional theory approach toward substituent effect in Meerwein-Eschenmoser-Claisen rearrangement.

B3LYP/6-31 G(d) level of theory has been used for the examination of substituent effect in the concerted step of the Meerwein-Eschenmoser-Claisen rearrangement. In this regard, the effect of NO(2) and NH(2) groups in different positions has been investigated. The obtained results show that substituent effect is very sensitive to its position and configuration. Electron withdrawing and electron donating groups in different positions and various configurations show different and sometimes opposite results.

Pyridine-functionalized MCM-41 as an efficient and recoverable catalyst for the synthesis of pyran annulated heterocyclic systems.

Pyridine-functionalized MCM-41 catalyzed reactions between tetracyanoethylene and various activated CH-acid compounds are described. These reactions afford the corresponding pyran annulated heterocyclic ring systems in high yields at room temperature within a few minutes. The work-up procedure is very simple and the products do not require further purification. The catalyst can be recycled and reused for several times without observable loss of performance.