Cyclopentadithiophene Derivatives Research Articles

A computational study for optical and nonlinear optical properties of distinctive V-shaped cyclopenta dithiophene derivatives

A computational study for optical and nonlinear optical properties of distinctive V-shaped cyclopenta dithiophene derivatives

Modulating chemical composition of the D-π-D-A-D type copolymers to obtain soluble Neutral-state green or dark Yellowish-black films with Multi-color electrochromism

Novel high-performance D-π-D-A-D type polymeric electrochromic materials consisting of phenylene π-bridged core alternated with the donor cyclopentadithiophene derivatives and the D-A-D moiety thiophene-diketopyrrolo[3,4-c]pyrrole-thiophene (TDPPT), differing by the ratio of donor to acceptor units incorporated, were achieved by Suzuki cross-coupling reaction. The polymer films displayed intense dual visible absorptions in their neutral states, which were modulated both in the positions and relative intensities by regulating the chemical composition as well as the donor-to-acceptor ratio in the polymer backbone, allowing the facile manipulation of the neutral-state colors. The polymer PBDC-1 exhibited a deep green neutral-state color. PBDC-2 and PBDC-3 also demonstrated two strong and broad absorptions, but a relative small gap of transmission in the orange-yellow region, giving the films dark yellowish-black color. In situ optical monitoring revealed that all the polymers underwent surprising multi-color variations upon the redox cycling, simultaneous with fast switching speeds, high coloration efficiencies, and large optical contrasts.

Difluorinated cyclopentadithiophene derivatives for green emitters in organic light-emitting diodes: A theoretical investigation

Two types of difluorinated conjugated systems incorporating bridged cyclopentadithiophene, alternating fumaronitrile and 1,3,4-oxadiazole were designed and theoretically studied by density functional theory and its time-dependent extension with the B3LYP hybrid functional and the 6–311g(d,p) and 6–311++g(d,p) basis sets in tetrahydrofuran. The designed materials are denoted FCFO-1 (>CO) and FCFO-2 (>CC–(CN)2. The electronic band gap ranges from 2.46 eV (FCFO-1) to 2.30 eV (FCFO-2). The difference in optical behaviors may originate from the effect of the bridging group on cyclopentadithiophene derivatives. The materials were examined as green emitters (519–564 nm). Organic light-emitting diodes based on these new fluorescent materials [indium tin oxide anode (100 nm)/N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (hole-injection layer) (150 nm)/FCFO-1 or FCFO-2 (50 nm)/Al cathode (100 nm)], were theoretically designed. The current-voltage characteristics were simulated, and the threshold voltages were estimated to be 3.25 V for FCFO-1 and 2.17 V for FCFO-2. Electric dipole moment calculations show the molecules possess large electric dipole moments (approximately 9.88 D for FCFO-1 and approximately 11 D for FCFO-2) and they thus exhibit excellent nonlinear optical properties.

Synthesis and Application of Cyclopentadithiophene Derivatives

Synthesis and Application of Cyclopentadithiophene Derivatives

Cyclopentadithiophene derivatives: a step towards an understanding of thiophene copolymer excited state deactivation pathways

In (cis) cyclopentadithiophene, the large Stokes shift is due to a bond length change whereas with α2 (trans) it involves a change in the dihedral angle.

Novel dyes of branched chain polymeric metal complexes based on cyclopentadithiophene derivatives: synthesis, characterization and photovoltaic performance for dye-sensitized solar cells

In this work, four novel D–A polymeric metal complexes (P1–P4) were designed and synthesized as dye sensitizers for high-performance dye-sensitized solar cells (DSSCs), which use cyclopentadithiophene or fluorene derivatives as donor (D) and the 2-(2′-pyridyl)benzimidazole derivative as acceptor (A). All polymers exhibited good thermal stability for their application in DSSCs. DSSCs based on P1 exhibited the best power conversion efficiency of 2.49 % with the cyclopentadithiophene derivative as donor and Cd(II) as coordination ion, which can be attributed to their stronger absorption in the UV–visible region and lower band gap. This study will pave a new path to design novel conjugated organic polymers as dyes for DSSCs.

Synthesis and Photovoltaic Properties of the Novel Dye of Branched Chain Polymeric Metal Complexes with Cyclopentadithiophene Derivatives as a Donor

ABSTRACTFour novel donor‐π‐acceptor dyes (P1–P4) based on branched chain polymeric metal complexes were designed and synthesized, which use cyclopentadithiophene or fluorene derivatives as an electron donor (D), phenanthroline metal complex as an electron acceptor (A), and thiophene as a π‐bridge (π). The photovoltaic performances of dye‐sensitized solar cells (DSSCs) based on the four polymers were investigated. The results show that they all have good thermal stability (Td, P1 313°C, P2 320°C, P3 306°C, P4 340°C), and the dyes with cyclopentadithiophene derivatives as a donor (P1 and P2) show higher power conversion efficiency (P1 2.41%, P2 2.31%) than that with fluorene derivatives (P3 1.65%, P4 1.52%) under standard illumination due to their broader absorptions in the UV–visible region and lower band gaps. It indicates a new way to design stable and highly efficient DSSCs with novel conjugated organic polymers as dyes.

Small Molecules of Cyclopentadithiophene Derivatives: Effect of Sulfur Atoms Position and Substituted Groups on Their UV-abs Properties.

Thiophene-based organic semiconductors used as the active components have received much attention. Their photoelectric properties can be easily tuned with various substitutions at different positions on molecular structures. Here, we synthesized series cyclopentadithiophene (CDT) derivatives with sulfur atoms at ortho- (o-CDT), meta- (m-CDT) and para-position (p-CDT) of the bridge carbon. These CDT derivatives were substituted by carbonyl/dicyanomethylene at the bridge position and/or by phenyl groups at α position, respectively. Due to the different conjugation extent and the variation of donor-acceptor (D-A) interaction originating from the change of sulfur atom position, diverse absorption spectra were observed. Especially for dicyanomethylene substituted o-CDT with phenyl as substitution group (DPCN-o-CDT), its absorption spectrum covers the whole region of visible light. Combining with the electrochemical behaviors and theoretical calculations, it was found that the sulfur atoms mainly contribute to the molecular conjugation in these CDT derivatives, especially for o-CDT derivatives. For phenyl groups, they primarily act as electron donor in m-CDT derivatives, and chiefly contribute to molecular conjugation in p-CDT derivatives, and simultaneously work as electron donor and conjugation component in o-CDT derivatives, respectively.

The effect of heteroatom conformation on optoelectronic properties of cyclopentadithiophene derivatives

Cyclopentadithiophene (CPDT) derivatives with different heteroatom conformations have been synthesized. The optical, electrochemical and charge transport properties of these molecules are reported. The CPDT-anti-ketone not only exhibits the lowest optical and electronic bandgaps, but also exhibits reasonable hole mobility, 3 × 10(-3) cm(2) (V s)(-1). Changing the carbonyl conformation to the syn position or incorporating the imine functionality results in a blue-shift in the lower energy band of the absorption spectrum indicative of the increased bandgaps.

Structural, optical, and charge transport properties of cyclopentadithiophene derivatives: a theoretical study

Density functional theory calculations were carried out to investigate the structural and opto-electronic properties of cyclopenta[2,1-b:3,4-b′]dithiophene (CPDT) derivatives. The ground state, cationic and anionic geometries of cyclopentadithiophene derivatives were optimized at B3LYP/6-311G(d,p) level of theory. Based on these geometries, ionic state properties such as ionization potentials, electron affinities, hole extraction potential, and electron extraction potential of cyclopentadithiophene derivatives have been calculated. The charge transfer integral, spatial overlap integral, and site energy were calculated from the matrix elements of Kohn–Sham Hamiltonian. Computed results show that the mobility of charge carriers in CPDT derivatives is strongly affected by the substitution of electron withdrawing group at bridge-head and α-positions. The excited state geometry of CPDT derivatives were optimized using configuration interaction singles method. On the basis of ground and excited states geometry, absorption and emission spectra of cyclopentadithiophene derivatives were calculated using the time-dependent density functional theory method. It has been observed that the substitution of EWG in cyclopentadithiophene core alters the absorption and emission spectra. The nonlinear optical property of CPDT derivatives have been studied through computed static polarizability and first hyperpolarizability.

Bridgehead Imine Substituted Cyclopentadithiophene Derivatives: An Effective Strategy for Band Gap Control in Donor–Acceptor Polymers

Bridgehead imine substituted cyclopentadithiophene structural units offer the opportunity to modify the electronic properties, in particular, the HOMO–LUMO energy levels of donor–acceptor polymers with unprecedented precision. Utilizing a common synthetic pathway, copolymers with high average molecular weights, a variety of functionality, and properties suitable for solar cell incorporation can be generated. The fabrication of organic photovoltaic devices with these new materials is demonstrated.

Fluorescent cyclopentadithiophene derivatives having phenyl-substituted silyl moieties

4,4-Dimethylcyclopenta[2,1- b:3,4- b′]dithiophene derivatives bearing trimethyl-, dimethylphenyl-, diphenylmethyl-, or triphenyl-silyl moieties were synthesized. The introduction of the silyl moieties onto cyclopenta[2,1- b:3,4- b′]dithiophene induced fluorescent emission as well as the bathochromic shift of wavelength at the maximum absorption and fluorescence. It was found that the larger number of phenyl group on silyl moiety resulted in the higher fluorescence quantum yield.