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Abstract The structural modification of hole‐transporting materials (HTMs) is an effective strategy for enhancing photovoltaic performance in perovskite solar cells (PSCs). Herein, a series of dithienopyran (DTP)‐based HTMs (Me‐H, Ph‐H, CF3‐H, CF3‐mF, and CF3‐oF) is designed and synthesized by substituting different functional groups on the DTP unit and are used fabricating PSCs. In comparison with Me‐H having two methyl substituents on the dithienopyrano ring, the Ph‐H having two phenyl substituents on the ring exhibits higher PCEs. Notably, the incorporation of trifluoromethyl groups in CF3‐H endows the molecule with a larger dipole moment, deeper HOMO energy level, better film morphology, closer molecular stacking, more efficient defect‐passivation, enhanced hydrophobicity, and better photovoltaic performance when compared with the Ph‐H counterpart. Furthermore, the HTMs of CF3‐mF and CF3‐oF, which feature fluorine‐substituted triphenylamine, demonstrated excellent film‐forming properties, more suitable energy levels, enhanced charge mobility, and improved passivation of the buried interface between HTMs and perovskite. As a result, PSCs employing CF3‐mF and CF3‐oF gave impressive PCEs of 23.41 and 24.13%, respectively. In addition, the large‐area (1.00 cm2) PSCs based on CF3‐oF achieved a PCE of 22.31%. Moreover, the PSCs devices with CF3 series HTMs exhibited excellent long‐term stability under different conditions.

A two-dimensional (2D) coordination polymer, [Co(4-dpds)(bdc)(H2O)2]·4-dpds (1) (4-dpds = 4,4′-dipyridyldusulfide and bdc2− = dianion of benzenedicarboxylic acid), has been synthesized and structurally determined by single-crystal X-ray diffractometer. In 1, the bdc2− and 4-dpds both act as bridging ligands connecting the Co(II) ions to form a 2D wrinkled-like layered coordination polymer. Two wrinkled-like layered coordination polymers are mutually penetrated to generate a doubly interpenetrated framework, and then extended to its 3D architecture via the supramolecular forces between doubly interpenetrated 2D frameworks and free 4-dpds ligands by intermolecular O–H⋅⋅⋅N hydrogen bonding interaction. Crystal packing arrangements were characterized by fingerprint plots, which were derived from the Hirshfeld Surfaces analysis, and showed that intermolecular hydrogen bonding interactions are the most important interactions on the construction of the crystal 1.

Ab initio calculation of both the lowest singlet and triplet electronic states of BN has been performed by the fixed-node Ornstein-Uhlenbeck diffusion quantum Monte Carlo method with the floating spherical Gaussian orbitals and spherical Gaussian geminals. The Monte Carlo calculation gives equilibrium bond lengths and equilibrium harmonic frequencies of 1.3317(7) Å and 1529(7) cm-1, respectively, for the lowest triplet state and 1.2751(7) Å and 1709(8) cm-1, respectively, for the lowest singlet state. Also, the Monte Carlo calculation reports an energy separation of 178(83) cm-1 between the two electronic states and recommends the ground state is the lowest triplet state. [ABSTRACT FROM AUTHOR]

This article accesses the performance of the Ornstein–Uhlenbeck diffusion quantum Monte Carlo with regard to the calculation of molecular geometries and harmonic frequencies of H[sub 2], LiH, HF, Li[sub 2], LiF, CO, N[sub 2], and F[sub 2] molecules. A comparison of the results for the eight first-row diatomic molecules from experiments, CCSD(T)/6-311G(3df,3pd) and CCSD(T)/cc-pV5Z levels of theory as well as our work is given. The results presented show that quantum Monte Carlo is becoming powerful tools for ab initio electronic structure calculations. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

This article describes an approach in determination of equilibrium geometries and harmonic frequencies of molecules by the Ornstein–Uhlenbeck diffusion quantum Monte Carlo method based on the floating spherical Gaussians. In conjunction with a projected and renormalized Hellmann–Feynman gradient and an electronic energy at variational Monte Carlo and diffusion quantum Monte Carlo, respectively, the quasi-Newton algorithm implemented with the Broyden–Fletcher–Goldfarb–Shanno updated Hessian was used to find the optimized molecular geometry. We applied this approach to N[sub 2] and H[sub 2]O molecules. The geometry and harmonic frequencies calculated were consistent with some sophisticated ab initio calculated values within reasonable statistical uncertainty.© 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Application of the Ornstein—Uhlenbeck diffusion quantum Monte Carlo method in combination with a trial wave function constructed from the floating spherical Gaussian orbitals and spherical Gaussian geminals to studies on the equilibrium structures and harmonic frequencies of ethane and ozone is presented. These Monte Carlo computed results are compared with those of experiments as well as the coupled cluster methods with the correlation consistent basis sets for the two molecules. For ozone, we also compare the Monte Carlo results with the results from multireference calculations. [ABSTRACT FROM AUTHOR]

In this article, we examined the Gibbs energy of activation for the Z/E thermal isomerization reaction of (1Z)-acetaldehyde hydrazone and (1Z)-acetaldehyde N,N-dimethylhydrazone, at 298.15 K in the solvent of cyclohexane. We carried out computations employing both the Gaussian-4 (G4) theory and the coupled cluster method using both single and double substitutions and triple excitations noniteratively, CCSD(T). The CCSD(T) energy is extrapolated to the complete basis set (CBS). We compared the calculated results to the available experimental observation. It appeared that both G4 and CCSD(T)/CBS computations overestimated the experimental value by as much as about 6 and 12 kcal/mol in the present two cases. We discussed possible sources of error and proposed the experimental kinetic data could be questionable. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009 [ABSTRACT FROM AUTHOR]