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Two new organic dyes incorporating triphenylamine as a donor and oligothienylenevinylene as a bridge have been synthesized. The new dyes cover the entire visible region and have a power conversion of up to 6.25%. [ABSTRACT FROM AUTHOR]

An organic dye containing two D-π-A branches linkedwitha thiophene unit has been designed and synthesized for efficient dye-sensitizedsolar cells (DSSCs). As compared to the rod-shape of the single D-π-Aanalogue dye, the cross shape of the double D-π-A branched dyeis favorable for reducing intermolecular interaction and retardingcharge recombination. Controlled intensity modulated photovoltagespectroscopy reveals that electron lifetime for the double D-π-Adye-based DSSC is 14-fold longer than that for the corresponding singleD-π-A dye-based DSSC. Linking two D-π-A branches witha thiophene unit increases open-circuit photovoltage by 100 mV andshort-circuit photocurrent by 4.10 mA cm–2. As aconsequence, power conversion efficiency is enhanced by about 2-fold.This work presents a new route to designing sensitizers with highsuppression ability of charge recombination toward high-performanceDSSCs. [ABSTRACT FROM AUTHOR]

A new class of organic sensitizers incorporating a benzo[1,2-b:4,5-b′]dithiophene (BDT) unit as conjugated spacer has been synthesized and successfully used for dye-sensitized solar cells (DSSCs). The length of the π-conjugated spacers has a strong impact on electro-optical properties of these dyes, leading to the conversion efficiencies ranging from 4.17 to 5.68% under AM 1.5 G irradiation. This result indicates that the BDT unit is a promising candidate in organic sensitizers. [ABSTRACT FROM AUTHOR]

Through a rational design, a novel Donor–Acceptor π-conjugated (D-π-A) blue fluorescent indenofluorene dye, DA-DSF-IF, has been synthesized for application in single-layer Small Molecule Organic Light Emitting Diodes (SMOLEDs). This new blue emitter possesses bipolar properties as well as good morphological and emission color stabilities and has been successfully used in a blue emitting single-layer SMOLED, with performances impressively magnified compared to a nonbipolar indenofluorene emitter. [ABSTRACT FROM AUTHOR]

A series of symmetrical D−π-A−π-D molecules based on benzothiadiazole and oligo(thienylenevinylene)s were facilely developed. The investigation of their photophysical and electrochemical properties demonstrated that these compounds exhibited broad absorption covering the whole visible range with appropriate energy levels for light-harvesting donors. [ABSTRACT FROM AUTHOR]

A new organic fluorescent dye, 2,4-dichloro-6-[p-(N,N-diethylamino)biphenylyl]-1,3,5-triazine (DBQ), with an electron withdrawing−donating pair bridged by a twistable aromatic chain has been synthesized. DBQ exhibits high fluorescence quantum yields (0.96 in hexane and 0.71 in THF), high extinction coefficients, and an excitation window extending up to ∼480 nm. Due to the strong intramolecular charge transfer character, DBQ shows obviously solvent-dependent Stokes shifts with a value as high as 6360 cm−1in THF and controllable fluorescence emission in the visible region from “blue” to “orange”. The axially chiral structures of DBQ crystals were clearly revealed by the X-ray analyses and CD spectroscopy measurements. Two enantiomers of DBQ were obtained by spontaneous resolution upon crystallization without any chiral auxiliary. The low rotation barriers around the interannular bonds in DBQ molecules resulted in an efficient and selective multiplication of each of the chiral structures when DBQ crystallized in THF at room temperature in the presence of an enantiopure crystal seed, leaving racemized DBQ molecules in the solution. The special crystalline properties of DBQ provided a new approach to the design and synthesis of organic chiral crystals. The photophysical properties of DBQ make it promising in the preparation of new fluorescent probes with high sensitivity. [ABSTRACT FROM AUTHOR]

We report the synthesis and unique spectroscopic properties of organic styryl dye nanoparticles. Aqueous-phase ion association between a cationic styryl dye 2-(4-(dimethylamino)styryl)-1-ethylpyridinium (DASPE), possessing both electron donor and acceptor groups in its molecule, and tetraphenylborate (TPB) or tetrakis(4-fluorophenyl)borate (TFPB) anion, in the presence of poly(vinylpyrrolidone), produces the ion-based dye (DASPE) nanoparticles of ∼30−100 nm in diameter. Absorption spectra of the DASPE nanoparticles show a large bathochromic shift in comparison with that of the dye monomer in water. Quantum chemical calculations demonstrate that ion-pair formation brings about a large internal rotation around a single bond in DASPE, and this internal twisting as well as local polarity of the counteranion have a strong influence on the red shift of the optical spectra. Furthermore, nanoparticle formation results in enhanced fluorescence of DASPE: more than a 20-fold enhancement in the fluorescence quantum yield as compared to that of the dye monomer in water, giving a new methodology for the synthesis of fluorescent organic nanoparticles. The observed fluorescence would come from an intramolecular charge-transfer (ICT) excited state stabilized by the matrix of TPB or TFPB, and the enhancement is due to both the high rotational resistance for the single bond in DASPE and the matrix polarity effect that can suppress the nonradiative processes. [ABSTRACT FROM AUTHOR]

A series of structurally simple dipolar light-harvesting organic dyes featuring 1,3-cyclohexadiene in the aromatic π framework for dye-sensitized solar cells has been synthesized and characterized. The highest conversion efficiency of the DSSCs based on these dyes can reach up to 4.4%. [ABSTRACT FROM AUTHOR]

New metal-free dyes with a furan moiety in the conjugated spacer between the arylamine donor and the 2-cyanoacrylic acid acceptor have been synthesized, and high efficiency dye-sensitized solar cells were fabricated using these molecules as light-harvesting sensitizers. [ABSTRACT FROM AUTHOR]

The article discusses the syntheses and spectroscopic properties of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) dyes and their derivatives. According to the authors, the dyes tend to be strongly ultraviolet-absorbing small molecules that emit relatively sharp fluorescence peaks with high quantum yields. They add that the dyes are relatively insensitive to the polarity and pH of their environment and are reasonably stable to physiological conditions.

The article describes the design and synthesis of a molar extinction organic sensitizer coded C203 with a fused dithienothiophene unit for efficient and stable dye-sensitized solar cells. According to the authors, a ~7% cell with an organic dye showing an excellent stability measured under the thermal and light-soaking dual stress was demonstrated in combination with a solvent-free ionic liquid electrolyte.