Polydentate Ligand Reinforced Chelating to Stabilize Buried Interface toward High-Performance Perovskite Solar Cells.

The instability of the buried interface poses a serious challenge for commercializing perovskite photovoltaic technology. Herein, we report a polydentate ligand reinforced chelating strategy to strengthen the stability of buried interface by managing interfacial defects and stress. The bis(2,2,2-trifluoroethyl) (methoxycarbonylmethyl)phosphonate (BTP) is employed to manipulate the buried interface. The C=O, P=O and two -CF3 functional groups in BTP synergistically passivate the defects from the surface of SnO2 and the bottom surface of the perovskite layer. Moreover, The BTP modification contributes to mitigated interfacial residual tensile stress, promoted perovskite crystallization, and reduced interfacial energy barrier. The multidentate ligand modulation strategy is appropriate for different perovskite compositions. Due to much reduced nonradiative recombination and heightened interface contact, the device with BTP yields a promising power conversion efficiency (PCE) of 24.63 %, which is one of the highest efficiencies ever reported for devices fabricated in the air environment. The unencapsulated BTP-modified devices degrade to 98.6 % and 84.2 % of their initial PCE values after over 3000 h of aging in the ambient environment and after 1728 h of thermal stress, respectively. This work provides insights into strengthening the stability of the buried interface by engineering multidentate chelating ligand molecules.

Cu(II) complex of pyridine-based polydentate as a novel, efficient, and highly reusable catalyst in C-N bond-forming reaction.

In this paper, a highly reusable copper(II) complex of pyridine-based polydentate is able to efficiently catalyze a C-N bond-forming reaction under mild conditions. A variety of N-heterocyclic and amine compounds arylated with different aryl iodides, bromides, and chlorides produced N-substituted compounds in good to excellent yields. This methodology can be also used for the arylation of N-unsubstituted compounds using arylboronic acids under solvent-free conditions. All reactions are performed in short times under air, and the catalyst can be reused up to seven times.

Stabilizing Top Interface by Molecular Locking Strategy with Polydentate Chelating Biomaterials toward Efficient and Stable Perovskite Solar Cells in Ambient Air.

The instability of top interface induced by interfacial defects and residual tensile strain hinders the realization of long-term stable n-i-p regular perovskite solar cells (PSCs). Herein, one molecular locking strategy is reported to stabilize top interface by adopting polydentate ligand green biomaterial 2-deoxy-2,2-difluoro-d-erythro-pentafuranous-1-ulose-3,5-dibenzoate (DDPUD) to manipulate the surface and grain boundaries of perovskite films. Both experimental and theoretical evidence collectively uncover that the uncoordinated Pb2+ ions, halide vacancy, and/or I─Pb antisite defects can be effectively healed and locked by firm chemical anchoring on the surface of perovskite films. The ingenious polydentate ligand chelating is translated into reduced interfacial defects, increased carrier lifetimes, released interfacial stress, and enhanced moisture resistance, which should be liable for strengthened top interface stability and inhibited interfacial nonradiative recombination. The universality of the molecular locking strategy is certified by employing different perovskite compositions. The DDPUD modification achieves an enhanced power conversion efficiency (PCE) of 23.17-24.47%, which is one of the highest PCEs ever reported for the devices prepared in ambient air. The unsealed DDPUD-modified devices maintain 98.18% and 88.10% of their initial PCEs after more than 3000 h under a relative humidity of 10-20% and after 1728 h at 65 °C, respectively.

Molecular spectra of a D-π-A typed polydentate ligand chromophore and its simultaneous response to trace Cu2+ and Co2.

A D-π-A conjugated polydentate ligand chromophore, N-8'-quinolyl-2,4,6- trihydroxyl benzamide (NQTB), was identified and synthesized using tri-hydroxyl phenol as donated-electron group, N-heterocycle quinoline as accepted-electron one and CN bond as bridged one. It was expected to chelate some heavy metal ions with prominent colorimetric or spectral changes. After its UV-vis absorption spectrum was investigated in detail, it was noted that NQTB possessed excellent spectral recognition ability to Cu2+ and Co2+ from other coexisting ions in aqueous. Under the optimized conditions, NQTB could simultaneously discriminate trace Cu2+ and Co2+ in environmental aqueous samples with low detection limits (1.9 × 10-8 mol/L and 5.7 × 10-8 mol/L) and satisfying analytical precisions (R.S.D. ≤3.3% and ≤2.6%) respectively. The sensing mechanism was confirmed to form some stable 5-membered-co-6-membered condensed rings between Cu2+/Co2+ and O/N atoms in NQTB.

Targeted synthesis of a polypyridyl polyoxometalate coordination complex using microwave-assisted reaction conditions.

In this article, we build upon our recent efforts that have focused on demonstrating the value of microwave-assisted synthesis in polyoxometalate (POM) chemistry. Herein, we report for the first time a microwave-assisted approach that enabled the facile preparation and crystallization of a large POM-containing coordination complex. The judicious selection and reaction of a sparingly water-soluble transition-metal-substituted polyanion (TMSP) salt with the tritopic ligand 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPT) in a mixed solvent system under moderately forcing conditions yields Ba9[(BIIIWVI11O39CoIII)3(C18H12N6)]·38H2O in moderate yield. Crystallographic analysis reveals significant intermolecular interactions between the organic ligand and neighbouring polyanions, predominantly C-H...O(water) in nature; meanwhile, the solvated regions of the crystal show significant disorder. To supplement the crystallographic study, combustion analysis, and IR and 1H NMR spectroscopic analyses were conducted, revealing good bulk purity and the stability of the complex in aqueous media.