Cyanoacrylic Acid Moiety Research Articles

Effect of heterocycle donor in 2-cyanoacrylic acid conjugated derivatives for DSSC applications

The impact of different electron donors of 2-cyanoacrylic acid derivatives on thermal, photophysical and electrochemical properties was investigated. The synthesized compounds form donor-acceptor (D-π-A) or acceptor-donor-acceptor (A-π-D-π-A) systems. Cyanoacrylic acid moiety as an electron acceptor was linked by different π-conjugated spacers including furan, pyrrole, indole, fluorene, dibenzofuran, carbazole and phenothiazine derivatives. Density functional theory was employed to obtain optimized geometries and to calculate the frontier molecular orbital energy of the studied molecules. The selected compounds were tested as sensitizers and co-sensitizer in dye-sensitized solar cells (DSSC). The fabricated DSSC were fully characterized by the incident photon to current conversion efficiency (IPCE), current-voltage (I-V) and electrochemical impedance spectroscopy (EIS) measurements. Device with di-anchoring sensitizer based on phenothiazine core showed the highest light-to-electricity conversion efficiency of 4.85%, even higher than commercial dye N719 (4.45%). Upon co-sensitization, the DSSC made of the N719 and di-anchoring molecule with phenothiazine core lead to further enhancement of conversion efficiency up to 5.60%.

Mono- and bi-cyanoacrylic acid substituted phenothiazine based sensitizers for dye sensitized solar cells

Phenothiazine and cyanoacrylic acid moiety based sensitizers were synthesized for dye sensitized solar cell application. Absorption and electrochemical properties of the sensitizers having mono- and bi-substituted cyanoacrylic acids were studied. The mono-cyanoacrylic acid substituted phenothiazine sensitizer has more light harvesting ability due to its high molar extinction coefficient. The photovoltaic performance of mono-cyanoacrylic acid substituted phenothiazine sensitizer was slightly greater compared to the bi-cyanoacrylic acid substituted phenothiazine sensitizer which was attributed to the effect of anchoring groups in the sensitizer.

Novel D-π-A organic dyes for DSSCs based on dibenzo[b,h][1,6]naphthyridine as a π-bridge

A new series of D-π-A organic dyes bearing fused dibenzo[b,h] [1,6]naphthyridine as the conjugated π-bridge, a cyanoacrylic acid moiety as the electron acceptor/anchoring group and different electron donor groups such as trimethoxy (5a), methoxy (5b) and dimethylamino (5c), were designed and synthesized for dye-sensitized solar cells (DSSCs), for the first time. The effect of donor groups on the performance of the DSSCs was systematically investigated using optical, electrochemical, theoretical and photovoltaic methods. Compared to dyes 5a and 5b, 5c showed a broader and more red-shifted absorption spectrum due to stronger electron donating ability of dimethylamino moiety, which is beneficial for absorbing more photons and thus generating high photocurrent. As a result, the DSSC fabricated with dye 5c has the highest power conversion efficiency of 5.02% (∼60% relative to N719-based standard cell), which is greater than those obtained by 5a and 5b-sensitized solar cells (3.22% and 2.13%, respectively) under standard air mass 1.5 global (AM 1.5 G) conditions. The improved photovoltaic performance mainly came from better photocurrent, as also confirmed by IPCE measurements. These results suggest that dibenzo[b,h][1,6]naphthyridine π-bridge bearing a strong electron donor group is a promising candidate to construct effective D–π–A organic dyes for DSSCs.

Performance Improvement of Dye-Sensitized Solar Cell by Phenanthrothiadiazole Unit-Based π-Conjugated Bridge

New organic dyes (D1, D2, and D3) containing a phenanthrothiadiazole unit as a π-conjugated system, a triarylamine as an electron donor, and a cyanoacrylic acid moiety as an electron acceptor were synthesized. The optical and electrochemical properties of dyes D1, D2, and D3 were investigated, and their performance as sensitizers in solar cells was evaluated. Dye-sensitized solar cells based on dye D3 produced a photon-to-current conversion efficiency of 5.23% (Jsc = 9.70 mA/cm2, Voc = 0.77 V, ff 0.70) under 100 mW/cm2 simulated AM 1.5 G solar irradiation.

Efficient organic dyes based on perpendicular 6,12-diphenyl substituted indolo[3,2-b]carbazole donor.

Three novel indolo[3,2-b]carbazole-based dyes have been designed and synthesized using a 6,12-diphenyl substituted indolo[3,2-b]carbazole core as a π-conjugated donor, a thiophene cyanoacrylic acid moiety as electron acceptor and anchoring group, together with triphenylamine, 3,4,5-trimethoxybenzene and bromine as a second donor group. The photophysical and electrochemical properties of the dyes have been investigated by UV spectroscopy and cyclic voltammetry (CV). Our study indicates that the second donor plays the important role of improving dye aggregation as well as tuning the photoelectronic properties. These indolo[3,2-b]carbazole based dyes show good performances with high Voc of 0.75 V, FF of 0.72, and a moderate PCE of 3.11% under AM 1.5 irradiation.

Spacer Effects of Donor-π Spacer-Acceptor Sensitizers on Photophysical Properties in Dye-Sensitized Solar Cells

The donor (D)-π spacer-acceptor (A) framework with electronic push–pull effects provides suitable molecular architectures for molecular design used as efficient light-harvesting sensitizers in dye-sensitized solar cells (DSSCs). Efficiencies of light harvesting and electron injection to the semiconductor of sensitizers play critical roles in DSSC performance. Here, we employed density functional theory to systematically and comparatively investigate the effects of π-spacers of D-π spacer-A types of dyes in solution and adsorbed on a (TiO2)38 anatase cluster on various photophysical properties. The absorption spectra, electron transfer probability, and related photophysical properties of D-π spacer-A types of dyes were investigated as functions of different types (thiophene (Th)- and phenyl (Ph)-based), lengths, and planarity (bridging two neighboring rings; dithieno-thiophene (DTT) and fluorene (FL)-based) of π-spacers, while the D (diphenylamine) and A (cyano-acrylic acid) moieties remained the same. Spa...

Tunable molecular weights of poly(triphenylamine‐2,2′‐bithiophene) and their effects on photovoltaic performance as sensitizers for dye‐sensitized solar cells

ABSTRACTDespite the huge progress achieved over the past decade, the relationship between the molecular weights of dyes and the performance of dye‐sensitized solar cells (DSSCs) remains unclear. In this article, we report on the fine control of the number‐average molecular weight (Mn) of poly(triphenylamine‐2,2′‐bithiophene) (PPAT) dyes with cyanoacrylic acid moieties as acceptors. We found a correlation between the Mn and photovoltaic performance of these polymers when they were used for DSSC applications. In this study, three samples (PPAT‐01, PPAT‐02, and PPAT‐03) with different Mn values (Mns = 1700, 2800, and 3500 g/mol) were prepared through the control of the polymerization time and characterized by analytical gel permeation chromatography and NMR. Under the same experimental conditions, the overall cell efficiency of the oligomer dyes showed a nonmonotonic tendency with increasing molecular weight. The power‐conversion efficiencies were 2.81% for PPAT‐01, 4.72% for PPAT‐02, and 1.88% for PPAT‐03. UV absorption measurements proved that PPAT‐03 formed aggregation, whereas PPAT‐01 and PPAT‐02 were in the monolayer state adsorbed on TiO2. The larger aggregation decreased charge transfer; thus, poor photoelectric conversion performance was observed. Furthermore, a higher molecular weight reduced the amount of PPAT‐03 adsorbed on TiO2, and this had a crucial effect on the performance of the cells because of the reduced photocurrent. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44182.

Synthesis and photovoltaic performance of dibenzofulvene-based organic sensitizers for DSSC

Three novel 2D-π-A metal-free organic dyes TK 7–9 containing a dibenzofulvene (DBF) linked to two thiophene units as the π-bridge, diarylamines with and without alkoxy chains as donor groups and the cyanoacrylic acid moiety as the acceptor and anchoring group were synthesized. The new dyes TK were characterized by optical and electrochemical measurements and density functional theory calculations and were used as sensitizers in liquid dye-sensitized solar cells. The effects of alkoxy-functionalization of donor moiety and of hexyl chain insertion onto one thienyl ring of π-linker on dye properties and performances were investigated. The results discover the dye TK7, bearing two simple diphenylamine groups without alkoxy chains, exhibits the best behavior in terms of light absorption and cell performance (PCE of 7.9% and photovoltaic parameters of Jsc of 17.82 mA cm−2, Voc of 670 mV and FF of 0.66). Lower power conversion efficiencies of 6.3% and 6.1% were found for TK8 and TK9, respectively, as a consequence of the presence of the alkoxy chains.

A new D–D–π–A dye for efficient dye-sensitized solar cells

New metal-free organic dye sensitizers containing mono-triphenylamine or bis-triphenylamine as the electron donor, a thiophene as the π-conjugated system, and a cyanoacrylic acid moiety as the electron acceptor were synthesized. The optical and electrochemical properties of the dyes were investigated, and their performance as sensitizers in solar cells was evaluated. Dye-sensitized solar cells based on dye containing bis-triphenylamine as the electron donor produced a photon-to-current conversion efficiency of 6.06% (Jsc=14.21mA/cm2, Voc=0.62V, ff=0.69) under 100mW/cm2 simulated AM 1.5G solar irradiation (100mW/cm2).

Synthesis and characterization of alkynylrhenium(I) tricarbonyl diimine complexes with fused thiophene and cyanoacrylic acid moiety

A series of alkynylrhenium(I) tricarbonyl diimine complexes with fused thiophene and cyanoacrylic acid moiety has been synthesized and characterized. A long-lived charge separated state of these complexes have been found. Preliminary studies to explore the utilization of these complexes as photosensitizers have also been made, which show photoresponse upon light illumination.

Fluoren‐9‐ylidene‐Based Dyes for Dye‐Sensitized Solar Cells

AbstractThree new dyes (1–3) with a triarylamine electron donor, a cyanoacrylic acid moiety as both electron acceptor and anchoring group, and a fluorene‐9‐ylidene moiety as an antenna were synthesized, and their electrochemical, photophysical, and photovoltaic properties were evaluated. Despite minor differences in absorption properties, as the starburst shape of the dyes increases and highly hindered hydrophobic groups are introduced, the measured open‐cell voltage (Voc) increased noticeably from 0.79 to 0.83 V, and the power‐conversion efficiency (PCE) value increased from 3.98 to 4.73 %.

D–π–A organic dyes with various bulky amine-typed donor moieties for dye-sensitized solar cells employing the cobalt electrolyte

SGT dyes containing various amine-typed donors as triphenylamine, bis-fluorenylamine and bis-phenothiazinylamine as the electron donor and a cyanoacrylic acid moiety as electron acceptor in D–π–A system, were developed to use in dye-sensitized solar cells (DSSCs). The SGT-102 dye containing bis-fluorenylamine had a better prevented charge recombination than other SGT dyes; leading to improvement in Voc. As a result, the conversion efficiency of 7.22% was achieved with a Jsc of 12.1mAcm−2, Voc of 865mV and a FF of 69.1 for the DSSC employing a dye containing the bulky bis-fluorenylamine donor unit, while the DSSC based on a dye containing the bulky bis-phenothiazinylamine donor unit showed a lower Jsc and Voc, leading to a lower efficiency of 5.16%, due to slow charge recombination associated with differently geometric structure orientations.

Rapid Synthesis of Thiophene‐Based, Organic Dyes for Dye‐Sensitized Solar Cells (DSSCs) by a One‐Pot, Four‐Component Coupling Approach

This one-pot, four-component coupling approach (Suzuki-Miyaura coupling/C-H direct arylation/Knoevenagel condensation) was developed for the rapid synthesis of thiophene-based organic dyes for dye-sensitized solar cells (DSSCs). Seven thiophene-based, organic dyes of various donor structures with/without the use of a 3,4-ethylenedioxythiophene (EDOT) moiety were successfully synthesized in good yields based on a readily available thiophene boronic acid pinacol ester scaffold (one-pot, 3-step, 35-61%). Evaluation of the photovoltaic properties of the solar cells that were prepared using the synthesized dyes revealed that the introduction of an EDOT structure beside a cyanoacrylic acid moiety improved the short-circuit current (Jsc) while decreasing the fill factor (FF). The donor structure significantly influenced the open-circuit voltage (Voc), the FF, and the power conversion efficiency (PCE). The use of a n-hexyloxyphenyl amine donor, and our originally developed, rigid, and nonplanar donor, both promoted good cell performance (η=5.2-5.6%).

Benzo[a]carbazole-Based Donor-π-Acceptor Type Organic Dyes for Highly Efficient Dye-Sensitized Solar Cells.

A novel class of metal-free organic dyes based on benzo[a]carbazole have been designed, synthesized, and used in dye-sensitized solar cells for the first time. These types of dyes consisted of a cyanoacrylic acid moiety as the electron acceptor/anchoring group and different electron-rich spacers such as thiophene (JY21), furan (JY22), and oligothiophene (JY23) as the π-linkers. The photophysical, electrochemical, and photovoltaic properties, as well as theoretical calculations of these dyes were investigated. The photovoltaic performances of these dyes were found to be highly relevant to the π-conjugated linkers. In particular, dye JY23 exhibited a broad IPCE response with a photocurrent signal up to about 740 nm covering the most region of the UV-visible light. A DSSC based on JY23 showed the best photovoltaic performance with a Jsc of 14.8 mA cm(-2), a Voc of 744 mV, and a FF of 0.68, achieving a power conversion efficiency of 7.54% under standard AM 1.5 G irradiation.

Synthesis of EDOT-containing organic dyes via one-pot, four-component Suzuki–Miyaura coupling and the evaluation of their photovoltaic properties

We have developed a one-pot, four-component Suzuki–Miyaura coupling for the synthesis of thiophene-based donor–π-bridge–acceptor (D–π–A) dyes for dye-sensitized solar cells. Two D–π–A dyes, 19 and 20, retaining 3,4-ethylenedioxythiophene (EDOT) beside a cyanoacrylic acid moiety, and one D–π–A dye 21 without EDOT (reference compound) were rapidly synthesized in accordance with the developed procedure. The measurement of the absorption spectra and the electrochemical properties of synthesized dyes, and the photovoltaic properties of solar cells that were prepared using the synthesized dyes 19–21, revealed that the dyes retaining only one EDOT beside a cyanoacrylic acid moiety would exert a high Jsc.

Novel π-extended porphyrin derivatives for use in dye-sensitized solar cells

Two novel donor-π-acceptor (D-π-A type) porphyrin dyes were successfully synthesized and use in a dye-sensitized solar cell (DSSC). The molecular structures of both porphyrins are composed of the same dialkyl-substituted diphenylamino unit acting as the donor part, and two bisalkoxyphenyl substituents at the 5,15-meso positions. The acceptor part is composed of different ethyne-linked π-extended bridges, and a cyanoacrylic acid (Dye I) or carboxyphenyl (Dye II) moiety acting as anchoring groups. In order to investigate the effects of including the π-extended bridge between the porphyrin and acceptor unit, two different π-extended bridges such as 2,2′-bithiophene and 2-(phenylethynyl)-thiophene, were employed. In particular, Dye II contains two triple bonds between donor substituted porphyrin and carboxylic acid group. These modifications could potentially reduce dye aggregation on the TiO 2 surface. The charge recombination resistance and diffusion length for the cells with Dye II were relatively higher for all the measured ranges of bias potentials, implying that electron recombination loss from injected electrons was highly suppressed when Dye II molecules were adsorbed on the TiO 2 surface. Eventually, Dye II containing a 2,2′-bithiophene π-spacer and anchored trough a carboxyphenyl group exhibited a superior power conversion efficiency of 6.7% under AM 1.5 illumination (100 mW.cm-2) in a photoactive area of 0.46 cm2 than Dye I with a 2-(phenylethynyl)thiophene (PCE = 3.5%) anchored through a cyanoacrylic group.

Influence of different substituents linked on fluorene spacer in organic sensitizers on photovoltaic properties

New metal-free organic sensitizers containing a fluorene unit as a π-conjugated system, a diphenylamine as an electron donor, and a cyanoacrylic acid moiety as an electron acceptor were synthesized and used for dye-sensitized solar cells. The photophysical and electrochemical properties of these dyes were investigated, and their performances as sensitizers in solar cells were measured. One solar cell containing the n-hexyl group in the fluorene unit produced an η of 5.15% (Jsc = 9.69 mA cm−2, Voc = 0.77 V, and ff = 0.70) under 100 mW cm−2 simulated AM 1.5 G solar irradiation (100 mW cm−2).

Series of D-π-A system based on isoindigo dyes for DSSC: Synthesis, electrochemical and photovoltaic properties

Novel D-π-A system organic dyes (ID1, ID2 and ID3) based on isoindigo (ID), which contain triphenylamine (ID1) or isoindigo (ID2 and ID3) as electron donors, isoindigo and thiophene as a π-conjugated system and a cyanoacrylic acid moiety as an electron acceptor and anchoring group, have been then synthesized and characterized by 1H NMR, UV–vis, CV. Dye-sensitized solar cells (DSSCs) based on these dyes were also fabricated and tested. As the photovoltaic performance tests demonstrated, the ID1 exhibits broader absorption spectra, higher maximum incident photon-to-current conversion efficiency (IPCE) and maximum photon-to-electron conversion efficiency (η) of 3.33% under 100mW/cm2 simulated AM 1.5G solar irradiation.

Charge Separation in Donor–Acceptor Spiro Compounds at Metal and Metal Oxide Surfaces Investigated by Surface Photovoltage

Molecules with donor (diphenylamine) and acceptor moieties (dicyano or cyanoacrylic acid moieties) were linked by fluorene or spirobisfluorene cores and the chain length has been changed by introducing a thiophene group between fluorene and diphenylamine. Four different kinds of fluorene and spirobisfluorene compounds were adsorbed from highly diluted solutions at ultra-thin nanoporous TiO2 (np-TiO2), Au and ITO surfaces. Charge separation has been investigated by surface photovoltage spectroscopy in the fixed capacitor and Kelvin probe arrangements in vacuum. Striking differences between the interaction of linking (dicyano or cyanoacrylic moieties) and different substrates were observed. Intra-molecular charge separation and electron injection have been distinguished and the directed adsorption of spiro compounds was deduced.

Synthesis of metal-free organic dyes containing tris(dodecyloxy)phenyl and dithienothiophenyl units and a study of their mesomorphic and photovoltaic properties

In this study we synthesized three metal-free organic dyes (Cpd11, Cpd16, and Cpd22) featuring 3,4,5-tris(dodecyloxy)phenyl and cyanoacrylic acid moieties as electron-donor and electron-acceptor/anchoring units, respectively, linked through various dithienothiophenyl conjugated spacers. Cpd16 exhibits mesomorphic properties, confirmed through polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction (XRD), due to the appropriate ratio of the lengths of its flexible chain to its rigid core. Molecular modeling of Cpd16, and its d-spacing determined from XRD data, verified the existence of a tilt angle in the SmC phase. Among these metal-free organic dyes, a dye-sensitized solar cell incorporating Cpd16 exhibited the best performance, presumably because of its better packing and its mesomorphic properties; the power conversion efficiency was 3.72% (Voc=0.58 V; Jsc=9.98 mA cm−2; FF=0.65) under simulated AM 1.5 irradiation (100 mW cm−2).