Similar or different: the same Spiro-core but different alkyl chains with apparently improved device performance of perovskite solar cells

By intelligently utilizing the odd-even effect existing in the melting points of alkanes as presented in the basic textbook of Organic Chemistry, different alkoxy groups were introduced to modify the structure of commercial Spiro-OMeTAD to give new Spiro derivatives of Spiro-OEtTAD, Spiro-OPrTAD, Spiro-OiPrTAD and Spiro-OBuTAD, with the aim to adjust the molecular packing status in perovskite solar cells as hole transporting compounds. Excitedly, with the introduction of ethoxy groups instead of the methoxy ones in Spiro-OMeTAD, Spiro-OEtTAD-based perovskite solar cells demonstrated the highest device performance of 20.16%, higher than that of Spiro-OMeTAD(18.64%).     

Rhodium-copper-TBAF-catalyzed hydroarylation of alkynes with aryl Trimethoxysilanes

A rhodium-copper-TBAF-catalyzed hydroarylation of alkynes with aryl trimethoxysilanes is described. The procedure utilizes a catalytic amount of copper(II) acetate, rhodium, PPh₃ and TBAF·3H₂O under air. Some asymmetric alkynes gave the products with high regioselectivities.     

Retardation of Trap-Assisted Recombination in Lead Halide Perovskite Solar Cells by a Dimethylbiguanide Anchor Layer

Reaching the full potential of solar cells based on photo-absorbers of organic-inorganic hybrid perovskites requires highly efficient charge extraction at the interface between perovskite and charge transporting layer. This demand is generally challenged by the presence of under-coordinated metal or halogen ions, causing surface charge trapping and resultant recombination losses. These problems can be tackled by introducing a small molecule interfacial anchor layer based on dimethylbiguanide (DMBG). Benefitting from interactions between the nitrogen-containing functional groups in DMBG and unsaturated ions in CH₃NH₃PbI₃ perovskites, the electron extraction of TiO₂ is dramatically improved in association with reduced Schottky–Read–Hall recombination, as revealed by photoluminescence spectroscopy. As a consequence, the power conversion efficiency of CH₃NH₃PbI₃ solar cells is boosted from 17.14 to 19.1 %, showing appreciably reduced hysteresis. The demonstrated molecular strategy based on DMBG enables one to achieve meliorations on key figures of merit in halide perovskite solar cells with improved stability.     

Palladium‐Catalyzed Kumada Reaction Employing Aminophosphine as Ligand

In this article a palladium‐catalyzed Kumada reaction was reported. The procedure was mild and tolerated a series of aryl bromides, affording the biaryls in good to excellent yield.