Type Organic Dyes Research Articles

Carbazole-Dendrimer-Based Donor−π–Acceptor Type Organic Dyes for Dye-Sensitized Solar Cells: Effect of the Size of the Carbazole Dendritic Donor

A series of novel D-π-A type organic dyes, namely, GnTA (n = 1-4), containing carbazole dendrons up to fourth generation as a donor, bithiophene as π-linkage, and cyanoacrylic acid as acceptor were synthesized and characterized for applications in dye-sensitized solar cells (DSSCs). The photophysical, thermal, electrochemical, and photovoltaic properties of the new dyes as dye sensitizers were investigated, and the effects of the carbazole dendritic donors on these properties were evaluated. Results demonstrated that increasing the size or generation of the carbazole dendritic donor of the dye molecules enhances their total light absorption abilities and unluckily reduces the amount of dye uptake per unit TiO2 area because of their high molecular volumes. The latter was found to have a strong effect on the power conversion efficiency of DSSCs. Importantly, electrochemical impedance spectroscopy (EIS) revealed that the size or generation of the donor had a significant influence on a charge-transfer resistance for electron recombination at the TiO2/electrolyte interface, causing a difference in open circuit voltage (Voc) of the solar cells. Among them, dye G1TA containing first generation dendron as a donor (having lowest molecular volume) exhibited the highest power conversion efficiency of 5.16% (Jsc = 9.89 mA cm(-2), Voc = 0.72 V, ff = 0.73) under simulated AM 1.5 irradiation (100 mW cm(-2)).

The design, synthesis, and characterization of D-π-A-π-A type organic dyes as sensitizers for dye-sensitized solar cells (DSSCs)

New D-π-A-π-A type organic dyes were synthesized and characterized as sensitizers for dye-sensitized solar cells (DSSCs). These dyes showed wide absorption spectra (300–625nm) and high molar extinction coefficients (ε467nm=60,911M−1cm−1). As dye sensitizers in DSSC, the D-π-A-π-A dye having a cyanoacrylic acid as an acceptor gave the best cell performance with a short-circuit photocurrent density (Jsc) of 7.14mA/cm2, an open-circuit voltage (Voc) of 0.62V, and a fill factor (FF) of 0.72, corresponding to an overall conversion efficiency η of 3.19%.

Dithieno[2,3-d;2′,3′-d′]benzo[1,2-b;4,5-b′]dithiophene based organic sensitizers for dye-sensitized solar cells

We report two novel D–π–A type organic dyes with a coplanar dithieno[2,3-d;2′,3′-d′]benzo[1,2-b;4,5-b′]dithiophene (DTBDT) as π-spacer for dye-sensitized solar cells.

Donor–Acceptor Organic Photosensitizers for Dye-Sensitized Solar Cells

Donor-acceptor type organic dyes (TA-EDOT-CA and TA-DM-EDOT-CA) containing thiophenevinylene spacer with 3,4-ethylenedioxythiophene (EDOT) substituent were synthesized and characterized for dye-sensitized solar cells (DSSCs). TA-EDOT-CA and TA-DM-EDOT-CA showed 26700 and 28000 M(-1) x cm(-1) of molar absorption coefficient at 458 nm and 459 nm of UV/vis absorption maximum wavelength, respectively. The overall solar-to-energy conversion efficiency of TA-EDOT-CA and TA-DM-EDOT-CA was 8.26% and 7.23% under AM 1.5 illumination (100 mW cm(-2)) without mask, respectively.

Enhanced Performance in Inverted Polymer Solar Cells with D–π–A‐Type Molecular Dye Incorporated on ZnO Buffer Layer

We report the superior characteristics of a ZnO buffer layer covered with a phenothiazine-based, π-conjugated donor-acceptor (D-π-A)-type organic dye (called "d-ZnO"). The use of this system for the performance enhancement of inverted bulk heterojunction polymer solar cells (PSCs) with the configuration of indium tin oxide/d-ZnO/polymer:PC71 BM/MoO3 /Ag (PC71 BM=[6,6]-phenyl C71 butyric acid methyl ester) is investigated. The layer of organic dyes anchored on the ZnO surface through carboxylate bonding reduces the shunt path on bare ZnO surface and provides better interfacial contacts and energy level alignments between the ZnO layer and the photoactive layer. This phenomenon consequently leads to highly enhanced photovoltaic parameters (fill factor, open-circuit voltage, and short-circuit current density) and power conversion efficiencies (PCEs). Inverted solar cells containing the d-ZnO layer not only revealed about 34% (PCE: 4.37%) and 18% (PCE: 7.11%) improvement in the PCEs of the representative poly-3(hexylthiophene) (P3HT) and low-band-gap poly{[4,8-bis-(2-ethyl-hexyl-thiophene-5-yl)-benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-alt-[2-(2'-ethylhexanoyl)-thieno[3,4-b]thiophen-4,6-diyl]} (PBDTTT-C-T) polymer systems, respectively, but also showed 2-4 times longer device lifetimes than their counterparts without the organic dye layer. These results demonstrate that this simple approach used in inverted PSCs with a metal oxide buffer layer could become a promising procedure to fabricate highly efficient and stable PSCs.

Synthesis and characterization of Y-shape electron donor–acceptor type organic dyes for dye-sensitized solar cells

Three Y-shape organic dyes, (Z)-3-(5-(3,5-bis(4-(9H-carbazol-9-yl)styryl)-4-methoxyphenyl)thiophen-2-yl)-2-cyanoacrylic acid (OD-1), (Z)-3-(5′-(3,5-bis(4-(9H-carbazol-9-yl)styryl)-4-methoxyphenyl)-2,2′-bithiophen-5-yl)-2-cyanoacrylic acid (OD-2) and (Z)-3-(5′-(3,5-bis(4-(9H-carbazol-9-yl)styryl)-4-methoxyphenyl)-3,4′-4″-trithiophenyl-5-yl)-2-cyanoacrylic acid (OD-3) were synthesized and used as sensitizers in nanocrystalline dye-sensitized solar cells (DSSCs). The introduction of the bis(carbazolylstyryl) units as an electron donor group and oligothiophene units as a both electron donors and π-spacers increased the conjugation length of the sensitizers and thus improved their molar absorption coefficient and light harvesting efficiency. DSSCs with the configuration of SnO2:F/TiO2/organic dye/liquid electrolyte/Pt devices were fabricated using these OD-1, OD-2 and OD-3 as a sensitizers. Among the devices, the DSSC composed of OD-3 exhibited highest power conversion efficiency of 3.03% under AM1.5G (100 mW cm−2).

Novel Organic D-π-2A Sensitizer for Dye Sensitized Solar Cells and Its Electron Transfer Kinetics on TiO2 Surface

Although numerous donor-π-acceptor (D-π-A) type organic dyes were investigated in order to replace the ruthenium polypyridyl complexes, there have been few reports of the D-π-2A system and the related electron transfer processes. In this work, a novel D-π-2A dye (coded as B2) was designed and synthesized for applications in dye-sensitized solar cells (DSSC). Obvious intramolecular charge transfer (ICT) between the donor and acceptor takes place under photoexcitation. Three frontier LUMOs (LUMO, LUMO+1, LUMO+2) of B2 are all located on the acceptor part, which is highly favorable for intramolecular electron transfer from the donor to acceptors and enhances the electron injection into the semiconductors. DSSC based on B2 showed a maximum monochromatic incident photon-to-current efficiency (IPCE) of 68% at 425 nm and an overall power conversion efficiency of 3.62% under simulated solar light (AM 1.5G, 100 mW cm–2) irradiation. Femtosecond and nanosecond TA, and TCSPC techniques were used to monitor the photo...

A donor–acceptor type organic dye connected with a quinoidal thiophene for dye-sensitized solar cells

A donor-acceptor type organic dye connected with a quinoidal thiophene as a π-conjugated chain, cyano-[5'-(4''-(N,N-dimethylamino)benzylidene)-5H-thiophen-2'-ylidene]acetic acid, was synthesized and applied to dye-sensitized solar cells (DSSCs). The absorption band of this quinoidal thiophene dye appeared at longer wavelengths than those of dyes with similar π-conjugation length, indicating the effective π-conjugation through the quinoidal structure. Although the excited state of the quinoidal thiophene dye is deactivated within several picoseconds even in solution, the DSSCs using the quinoidal thiophene dye showed incident photon to current conversion efficiency (IPCE) values of more than 90%, demonstrating the fast and efficient electron injection from the excited dye to TiO(2). By optimizing the fabrication conditions, the DSSC using this dye afforded a photoelectric conversion efficiency of 5.2%, without enlarging the molecular size.

Cyano or o-nitrophenyl? Which is the optimal electron-withdrawing group for the acrylic acid acceptor of D-π-A sensitizers in DSSCs? A density functional evaluation

We report a DFT, TDDFT and DFTB investigation of the performance of two donor-π-acceptor (D-π-A)-type organic dyes bearing different electron-withdrawing groups (EWG) for dye-sensitized solar cells (DSSCs) to evaluate which EWG is better for an acrylic acid acceptor, i.e., Cyano (-CN) or o-nitrophenyl (o-NO2-Ph). A series of theoretical criteria applied successfully in our previous work to explain the different performance of organic dyes related to open-circuit photovoltage (Voc) and short-circuit current density (Jsc) were used to evaluate the performance of the dyes with just different EWG. Our calculated results reveal that dye 2 with o-NO2-Ph has a larger vertical dipole moment, more electrons transferred from the dye to the semiconductor and a lower degree of charge recombination, which could lead to larger Voc; while the larger driving force and comparable light harvesting efficiency could lead to higher J sc , highlighting the potential of o-NO2-Ph as an EWG in an acrylic acid acceptor.

A novel D–A-π-A organic sensitizer containing a diketopyrrolopyrrole unit with a branched alkyl chain for highly efficient and stable dye-sensitized solar cells

A novel D-A-π-A type organic dye (YCD01) incorporating a diketopyrrolopyrrole unit with a branched alkyl chain was synthesized for dye-sensitized solar cells. YCD01 showed a high conversion efficiency of 7.43% (AM 1.5, 100 mW cm(-2)) with a J(sc) of 13.40 mA cm(-2), a V(oc) of 0.76 V, a FF of 0.73 and an excellent stability.

Molecular dynamics simulations on the aggregation behavior of indole type organic dye molecules in dye-sensitized solar cells

In Ti0(2) nanostructured dye-sensitized solar cells indole based organic dyes D149, D205 exhibits greater power conversion efficiency. Such organic dye molecules are easily undergone for aggregation. Aggregation in dye molecules leads to reduce electron transfer process in dye-sensitized solar cells. Therefore, anti-aggregating agents such as chenodeoxycholic acid are commonly added to organic dye solution in DSSCs. Studying aggregation of such dye molecules in the absence of semiconductors gives a detailed influence of anti-aggregating agents on dye molecules. Atomistic level of molecular dynamics (MD) simulations were performed on aggregation of indole type dye molecules D149, D205 and D205-F with anti-aggregating agent chenodeoxy cholic acid using AMBER program. The trajectories of the MD simulations were analyzed with order parameters such as radial atom pair distribution functions g(r), diffusion coefficients and root mean square deviations values. MD results suggest that addition of chenodeoxy cholic acid to dyes significantly reduces structural arrangement and increases conformational flexibility and mobility of dye molecules. The influence of semi-perfluorinated alkyl chains in indole dye molecules was analyzed. The parameters such as open-circuit voltage (V(oc)) and power conversion efficiency (η) of dye-sensitized solar cells are corroborated with flexibility and diffusion values of dye molecules.

ChemInform Abstract: Preparation of Donor—Acceptor Type Organic Dyes (VII) Bearing Various Electron‐Withdrawing Groups for Dye‐Sensitized Solar Cell Application.

ChemInformVolume 42, Issue 37 Organic Dyes ChemInform Abstract: Preparation of Donor—Acceptor Type Organic Dyes (VII) Bearing Various Electron-Withdrawing Groups for Dye-Sensitized Solar Cell Application. Youhei Numata, Photovoltaic Mater. Unit, Natl. Inst. Mater. Sci., Tsukuba, Ibaraki 305, JapanSearch for more papers by this authorIslam Ashraful, Photovoltaic Mater. Unit, Natl. Inst. Mater. Sci., Tsukuba, Ibaraki 305, JapanSearch for more papers by this authorYasuhiro Shirai, Photovoltaic Mater. Unit, Natl. Inst. Mater. Sci., Tsukuba, Ibaraki 305, JapanSearch for more papers by this authorLiyuan Han, Photovoltaic Mater. Unit, Natl. Inst. Mater. Sci., Tsukuba, Ibaraki 305, JapanSearch for more papers by this author Youhei Numata, Photovoltaic Mater. Unit, Natl. Inst. Mater. Sci., Tsukuba, Ibaraki 305, JapanSearch for more papers by this authorIslam Ashraful, Photovoltaic Mater. Unit, Natl. Inst. Mater. Sci., Tsukuba, Ibaraki 305, JapanSearch for more papers by this authorYasuhiro Shirai, Photovoltaic Mater. Unit, Natl. Inst. Mater. Sci., Tsukuba, Ibaraki 305, JapanSearch for more papers by this authorLiyuan Han, Photovoltaic Mater. Unit, Natl. Inst. Mater. Sci., Tsukuba, Ibaraki 305, JapanSearch for more papers by this author First published: 18 August 2011 https://doi.org/10.1002/chin.201137190Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume42, Issue37September 13, 2011 RelatedInformation

A novel metal-free panchromatic TiO2 sensitizer based on a phenylenevinylene-conjugated unit and an indoline derivative for highly efficient dye-sensitized solar cells

A novel donor-π-spacer-acceptor type organic dye (AK01) bearing a phenylenevinylene-conjugated system and a derivative of indoline donor was synthesized for dye-sensitized solar cells. AK01 showed panchromatic TiO(2) sensitization with high overall conversion efficiency of 6.2% under AM 1.5 illumination (100 mW cm(-2)).

Preparation of donor–acceptor type organic dyes bearing various electron-withdrawing groups for dye-sensitized solar cell application

Novel donor-π-spacer-acceptor type organic dyes bearing various electron-withdrawing groups on their acceptor part were synthesized by Knoevenagel condensation with acetic acid silyl ester derivatives. Dye-sensitized solar cells with the new dyes present solar light-to-electricity conversion efficiency of 2.51-4.05%.

2D‐Π‐A Type Organic Dyes Based on N,N‐Dimethylaryl Amine and Rhodamine‐3‐acetic Acid for Dye‐sensitized Solar Cells

AbstractThree organic dyes XS17–19 based on N,N‐dimethylaryl amine and rhodamine‐3‐acetic acid moieties are designed and synthesized. These dyes were applied into nanocrystalline TiO2 dye‐sensitized solar cells through standard operations, showing strong absorption bands at around 320–650 nm, and exhibiting broad IPCE responses. Cell based on XS17 gave a Jsc of 3.7 mA/cm2, an open circuit voltage of 550 mV, and a fill factor of 0.68, corresponding to an overall conversion efficiency of 1.4%. The low overall conversion efficiency is due to the modest IPCE and Voc values, which mainly stem from the acceptor of rhodanine‐3‐acetic acid.

Synthesis of new donor-fluorene-donor type organic dyes and their nonlinear absorption properties

We have synthesized two new donor-fluorene-donor type organic dyes (JFJ and TFT) which contain an alkyl fluorene unit bridging two donor groups. In order to enhance the two photon absorption efficiency the molecules were designed for facile donation of electrons from the substituent groups as well as for high coplanarity of the molecule. The wavelength of maximum absorption of TFT and JFJ appeared at 412 and 406nm, respectively. The photoluminescence (PL) spectra show maximum emission wavelengths of TFT and JFJ in chloroform solution at 465 and 495nm, respectively. From optical power limiting experiments, the nonlinear coefficients (σ2) of JFJ and TFT were found to be 8×10−21 and 4×10−21 cm4/GW, respectively.