Search results for "Dono"

Performance of dye-sensitized solar cells based on novel sensitizers bearing asymmetric double D−π−A chains with arylamines as donors

2012

Abstract Three novel, metal-free organic sensitizers bearing two asymmetric double donor-π-acceptor (D-π-A) chains ( DC1 - 3 ), each, and a reference dye containing single D-π-A chain ( SC ) with cyanoacrylic acid as electron acceptor are synthesized. Their photophysical, electrochemical properties and the performances of the corresponding dye-sensitized solar cells (DSSCs) are further investigated. The dyes, DC1, DC2 and DC3 contain one chain with diphenylamine and another chain with carbazole or phenothiazine as electron donor, while diphenylamine is only employed as electron donor in SC . Compared to the inferior solar energy to electricity conversion efficiency ( η ) of 2.82%, 4.66% and…

Donor-Acceptor Polythiophene Copolymers with Tunable Acceptor content for Photoelectric Conversion Devices

2004

The synthesis and characterization of a new series of substituted polythiophenes containing an electron acceptor anthraquinone moiety in the side chain are reported. The acceptor molar content was varied by the co-polymerization of both alkylthiophene and thiophene bearing anthraquinone monomers in different ratios. NMR analysis shows a good correlation between the monomer feed composition at the beginning of the polymerization and the actual unit composition of the backbone. The conjugation length and the chemical composition of the copolymers as a function of the molecular weight have been studied by size exclusion chromatography. Small angle X-ray scattering and UV-Vis absorption spectra…

THEORETICAL INSIGHTS ON O2 AND CO ADSORPTION ON NEUTRAL AND POSITIVELY CHARGED GOLD CLUSTERS

2006

With the aim of understanding the elementary steps governing the oxidation of CO catalyzed by dispersed or supported gold nanoclusters, the adsorption of molecular species, such as O2 and CO, on model neutral and positively charged clusters (Au(n)(m+) n = 1, 9, and 13; m = 0, 1, and 3) has been studied using an ab initio approach. The computed structural and thermodynamic data related to the binding process show that molecular oxygen interacts better with neutral clusters, acting as an electron acceptor, while CO more strongly binds to positively charged species, thus acting as an electron donor.

Designing conjugated microporous polymers for visible light-promoted photocatalytic carbon–carbon double bond cleavage in aqueous medium

2018

The production of valuable carbonyl compounds directly from alkenes via carbon–carbon double (CC) bond cleavage is a highly important reaction. As a promising alternative to traditional metal-catalyzed thermal reaction conditions, photocatalysis offers an environmentally friendly and sustainable synthetic strategy. However, most photocatalysts used so far were homogeneous, molecular and transition metal-based catalytic systems. Here, we report a structural design strategy of conjugated microporous polymers (CMPs) as a class of metal-free, heterogeneous, stable and reusable photocatalysts for visible light-promoted CC bond cleavage reaction. Via different electron donor and acceptor combinat…

DLPNO-CCSD(T) scaled methods for the accurate treatment of large supramolecular complexes

2017

In this work, we present scaled variants of the DLPNO-CCSD(T) method, dubbed as (LS)DLPNO-CCSD(T) and (NS)DLPNO-CCSD(T), to obtain accurate interaction energies in supramolecular complexes governed by noncovalent interactions. The novel scaled schemes are based on the linear combination of the DLPNO-CCSD(T) correlation energies calculated with the standard (LoosePNO and NormalPNO) and modified (Loose2PNO and Normal2PNO) DLPNO-CCSD(T) accuracy levels. The scaled DLPNO-CCSD(T) variants provide nearly TightPNO accuracy, which is essential for the quantification of weak noncovalent interactions, with a noticeable saving in computational cost. Importantly, the accuracy of the proposed schemes is…

Mimicking photosynthesis: covalent [60]fullerene-based donor–acceptor ensembles

2004

Abstract Within the context of exploring photophysical properties of [60]fullerene-based donor–acceptor ensembles, we highlight in this contribution an approach towards the synthesis of a novel series of donor-bridge-acceptor, C 60 –wire– ex TTF , ensembles that incorporate p -phenylenevinylene oligomers, in which the conjugation length has been systematically increased, as bridges that connect π-extended tetrathiafulvalenes (exTTF) (electron donor) with [60]fullerene (electron acceptor). This molecular design allows probing the effects of distance and rate, at which electron transfer processes occur, as well as the molecular-wire behavior of the oligo-PPV fragments.

Electronic communication through pi-conjugated wires in covalently linked porphyrin/C60 ensembles

2005

Novel photo- and electroactive triads, in which pi-conjugated p-phenylenevinylene oligomers (oPPVs) of different length are connected to a photoexcited-state electron donor (i.e., zinc tetraphenylporphyrin) and an electron acceptor (i.e., C(60)), were designed, synthesized, and tested as electron-transfer model systems. A detailed physicochemical investigation, concentrating mainly on long-range charge separation and charge recombination and kinetics, revealed small attenuation factors beta of 0.03+/-0.005 A(-1). Energy matching between the HOMO levels of C(60) and oPPVs emerged as a key parameter for supporting molecular-wire-like behavior: It favors rapid and efficient electron or hole in…

N-Glycosyl Amides: Removal of the Anomeric Protecting Group and Conversion into Glycosyl Donors.

2003

Synthesis and optoelectronic properties of chemically modified bi-fluorenylidenes

2016

The development of new light harvesting materials is a key issue for the progress of the research on organic & hybrid photovoltaics. Here, we report a new class of organic sensitizers based on the bi-fluorenylidene moiety as π-linker within the donor–π-linker–acceptor (D–π–A) scheme. The new dyes are endowed with electron donor and electron acceptor units at strategic positions in order to improve their electronic and light-harvesting properties. The comprehensive study of these compounds through the use of different experimental and theoretical techniques, provides an in-depth understanding of their electronic and photophysical properties, and reveal their interest as photovoltaic material…

Synthesis, modelling and characterisation of novel non-linear optical polymer containing indandionylpyridinium betaine units

1999

Abstract In the present article we report about the synthesis, quantum chemical model calculations and non-linear optical characterisation of a novel polyurethane based polymer — a bipolar organic compound N -(indan-1,3-dion-2-yl)-4- N ′, N ′-dialkyaminopyridinium betaine (IPB) containing charged electron donor and electron acceptor groups covalently bonded to polyurethane polymer backbone. This newly synthesised IPB containing polymer can be regarded as a promising thermally stable organic non-linear optical material with a long time performance for photonics applications.