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1.
A series of new push–pull organic dyes ( BT‐I – VI ), incorporating electron‐withdrawing bithiazole with a thiophene, furan, benzene, or cyano moiety, as π spacer have been synthesized, characterized, and used as the sensitizers for dye‐sensitized solar cells (DSSCs). In comparison with the model compound T1 , these dyes containing a thiophene moiety between triphenylamine and bithiazole display enhanced spectral responses in the red portion of the solar spectrum. Electrochemical measurement data indicate that the HOMO and LUMO energy levels can be tuned by introducing different π spacers between the bithiazole moiety and cyanoacrylic acid acceptor. The incorporation of bithiazole substituted with two hexyl groups is highly beneficial to prevent close π–π aggregation, thus favorably suppressing charge recombination and intermolecular interaction. The overall conversion efficiencies of DSSCs based on bithiazole dyes are in the range of 3.58 to 7.51 %, in which BT‐I ‐based DSSCs showed the best photovoltaic performance: a maximum monochromatic incident photon‐to‐current conversion efficiency (IPCE) of 81.1 %, a short‐circuit photocurrent density (Jsc) of 15.69 mA cm?2, an open‐circuit photovoltage (Voc) of 778 mV, and a fill factor (ff) of 0.61, which correspond to an overall conversion efficiency of 7.51 % under standard global AM 1.5 solar light conditions. Most importantly, long‐term stability of the BT‐I – III ‐based DSSCs with ionic‐liquid electrolytes under 1000 h of light soaking was demonstrated and BT‐II with a furan moiety exhibited better photovoltaic performance of up to 5.75 % power conversion efficiency.  相似文献   

2.
New hemicyanine dyes ( CM101 , CM102 , CM103 , and CM104 ) in which tetrahydroquinoline derivatives are used as electron donors and N‐(carboxymethyl)‐pyridinium is used as an electron acceptor and anchoring group were designed and synthesized for dye‐sensitized solar cells (DSSCs). Compared with corresponding dyes that have cyanoacetic acid as the acceptor, N‐(carboxymethyl)‐pyridinium has a stronger electron‐withdrawing ability, which causes the absorption maximum of dyes to be redshifted. The photovoltaic performance of the DSSCs based on dyes CM101 – CM104 markedly depends on the molecular structures of the dyes in terms of the n‐hexyl chains and methoxyl. The device sensitized by dye CM104 achieved the best conversion efficiency of 7.0 % (Jsc=13.4 mA cm?2, Voc=704 mV, FF=74.8 %) under AM 1.5 irradiation (100 mW cm?2). In contrast, the device sensitized by reference dye CMR104 with the same donor but the cyanoacetic acid as the acceptor gave an efficiency of 3.4 % (Jsc=6.2 mA cm?2, Voc=730 mV, FF=74.8 %). Under the same conditions, the cell fabricated with N719 sensitized porous TiO2 exhibited an efficiency of 7.9 % (Jsc=15.4 mA cm?2, Voc=723 mV, FF=72.3 %). The dyes CM101 – CM104 show a broader spectral response compared with the reference dyes CMR101 – CMR104 and have high IPCE exceeding 90 % from 450 to 580 nm. Considering the reflection of sunlight, the photoelectric conversion efficiency could be almost 100 % during this region.  相似文献   

3.
Reported are two highly efficient metal‐free perylene dyes featuring N‐annulated thienobenzoperylene (NTBP) and N‐annulated thienocyclopentaperylene (NTCP), which are coplanar polycyclic aromatic hydrocarbons. Without the use of any coadsorbate, the metal‐free organic dye derived from the NTCP segment was used for a dye‐sensitized solar cell which attained a power conversion efficiency of 12 % under an irradiance of 100 mW cm?2, simulated air mass global (AM1.5G) sunlight.  相似文献   

4.
Subporphyrinatoboron(III) (SubB) sensitizers were synthesized for use in dye‐sensitized solar cells (DSSCs). The prototype, which comprises a sterically demanding 3,5‐di‐tert‐butylphenyl scaffold, a meso‐ethynylphenyl spacer, and a cyanoacrylic acid anchoring group, achieved an open‐circuit voltage VOC of 836 mV, short‐circuit current density JSC of 15.3 mA cm?2, fill factor of 0.786, and a photon‐to‐current conversion efficiency of 10.1 %. Such astonishing figures suggest that a bright future lies ahead for SubB in the realm of DSSCs.  相似文献   

5.
Four new type II organic dyes with D‐π‐A structure (donor‐π‐conjugated‐acceptor) and two typical type II sensitizers based on catechol as reference dyes are synthesized and applied in dye sensitized solar cells (DSCs). The four dyes can be adsorbed on TiO2 through hydroxyl group directly. Electron injection can occur not only through the anchoring group (hydroxyl group) but also through the electron‐withdrawing group (? CN) located close to the semiconductor surface. Experimental results show that the type II sensitizers with a D‐π‐A system obviously outperform the typical type II sensitizers providing much higher conversion efficiency due to the strong electronic push‐pull effect. Among these dyes, LS223 gives the best solar energy conversion efficiency of 3.6%, with Jsc=7.3 mA·cm?2, Voc=0.69 V, FF=0.71, the maximum IPCE value reaches 74.9%.  相似文献   

6.
The efficient electron injection by direct dye‐to‐TiO2 charge transfer and strong adhesion of mussel‐inspired synthetic polydopamine (PDA) dyes with TiO2 electrode is demonstrated. Spontaneous self‐polymerization of dopamine using dip‐coating (DC) and cyclic voltammetry (CV) in basic buffer solution were applied to TiO2 layers under a nitrogen atmosphere, which offers a facile and reliable synthetic pathway to make the PDA dyes, PDA‐DC and PDA‐CV, with conformal surface and perform an efficient dye‐to‐TiO2 charge transfer. Both synthetic methods led to excellent photovoltaic results and the PDA‐DC dye exhibited larger current density and efficiency values than those in the PDA‐CV dye. Under simulated AM 1.5 G solar light (100 mW cm?2), a PDA‐DC dye exhibited a short circuit current density of 5.50 mW cm?2, corresponding to an overall power conversion efficiency of 1.2 %, which is almost 10 times that of the dopamine dye‐sensitized solar cell. The PDA dyes showed strong adhesion with the nanocrystalline TiO2 electrodes and the interface engineering of a dye‐adsorbed TiO2 surface through the control of the coating methods, reaction times and solution concentration maximized the overall conversion efficiency, resulting in a remarkably high efficiency.  相似文献   

7.
《化学:亚洲杂志》2017,12(3):332-340
A new series of acetylene‐bridged phenothiazine‐based di‐anchoring dyes have been synthesized, fully characterized, and used as the photoactive layer for the fabrication of conventional dye‐sensitized solar cells (DSSCs). Tuning of their photophysical and electrochemical properties using different π‐conjugated aromatic rings as the central bridges has been demonstrated. This molecular design strategy successfully inhibits the undesirable charge recombination and prolongs the electron lifetime significantly to improve the power conversion efficiency (η ), which was proven by the detailed studies of electrochemical impedance spectroscopy (EIS) and open‐circuit voltage decay (OCVD). Under a standard air mass (AM) 1.5 irradiation (100 mW cm−2), the DSSC based on the dye with phenyl bridging unit exhibits the highest η of 7.44 % with open‐circuit photovoltage (V oc) of 0.796 V, short‐circuit photocurrent density (J sc) of 12.49 mA cm−2 and fill factor (ff) of 0.748. This η value is comparable to that of the benchmark N719 under the same conditions.  相似文献   

8.
A series of organic dyes were prepared that displayed remarkable solar‐to‐energy conversion efficiencies in dye‐sensitized solar cells (DSSCs). These dyes are composed of a 4‐tert‐butylphenylamine donor group (D), a cyanoacrylic‐acid acceptor group (A), and a phenylene‐thiophene‐phenylene (PSP) spacer group, forming a D‐π‐A system. A dye containing a bulky tert‐butylphenylene‐substituted carbazole (CB) donor group showed the highest performance, with an overall conversion efficiency of 6.70 %. The performance of the device was correlated to the structural features of the donor groups; that is, the presence of a tert‐butyl group can not only enhance the electron‐donating ability of the donor, but can also suppress intermolecular aggregation. A typical device made with the CB‐PSP dye afforded a maximum photon‐to‐current conversion efficiency (IPCE) of 80 % in the region 400–480 nm, a short‐circuit photocurrent density Jsc=14.63 mA cm?2, an open‐circuit photovoltage Voc=0.685 V, and a fill factor FF=0.67. When chenodeoxycholic acid (CDCA) was used as a co‐absorbent, the open‐circuit voltage of CB‐PSP was elevated significantly, yet the overall performance decreased by 16–18 %. This result indicated that the presence of 4‐tert‐butylphenyl substituents can effectively inhibit self‐aggregation, even without CDCA.  相似文献   

9.
Four novel donor ? π‐bridge ? acceptor (D ? π ? A) polymeric metal complexes (P1–P4) based on 8‐hydroxyquinoline metal complexes were synthesized and tested for their performance in dye‐sensitized solar cells (DSSCs). The polymeric metal complexes dyes use alkoxy benzene or alkyl fluorene as the electron donor and C=C as π linker; the 8‐hydroxyquinoline derivative complex part was used as the electron acceptor and diaminomaleonitrile was used as ancillary ligand. The two strongly electron‐withdrawing cyano groups in the polymer structure can provide an efficient charge transport in the intramolecular between donor and acceptor parts. The thermal, photophysical, electrochemical and photovoltaic properties of these copolymers were investigated by TGA, differential scanning calorimetry, cyclic voltammetry and cureent density‐voltage curves, and the results showed that dye containing complex Zn(II) and alkoxy benzene unit benefited the generation of photocurrent and open‐circuit voltages, and a maximum power conversion efficiency of 1.91% (P2) was obtained, with an open‐circuit voltage of 0.71 V, a short‐circuit current density of 4.23 mA cm?2, and a fill factor of 38.6% under AM1.5G irradiation. The study results also show that the four polymers exhibit good thermal stability, indicating that these polymeric metal complexes are suitable for the fabrication processes of optoelectronic devices. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

10.
Luminescence downshifting (LDS) of light can be a practical photon management technique to compensate the narrow absorption band of high‐extinction‐coefficient dyes in dye‐sensitized solar cells (DSSCs). Herein, an optical analysis on the loss mechanisms in a reflective LDS (R‐LDS)/DSSC configuration is reported. For squaraine dye (550–700 nm absorption band) and CaAlSiN3:Eu2+ LDS material (550–700 nm emission band), the major loss channels are found to be non‐unity luminescence quantum efficiency (QE) and electrolyte absorption. By using an ideal LDS layer (QE=100 %), a less absorbing electrolyte (Co‐based), and antireflection coatings, approximately 20 % better light harvesting is obtained. If the absorption/emission band of dye/LDS is shifted to 800 nm, a maximal short‐circuit current density (Jsc) of 22.1 mA cm?2 can be achieved. By putting the LDS layer in front of the DSSC (transmissive mode), more significant loss channels are observed, and hence a lower overall efficiency than the R‐LDS configuration.  相似文献   

11.
Benzimidazole‐branched bi‐anchoring organic dyes that contained triphenylamine/phenothiazine donors, 2‐cyanoacrylic acid acceptors, and various π linkers were synthesized and examined as sensitizers for dye‐sensitized solar cells. The structure–activity relationships in these dyes were systematically investigated by using absorption spectroscopy, cyclic voltammetry, and density functional theory calculations. The wavelength of the absorption peak was more‐heavily influenced by the nature of the π linker than by the nature of the donor. For a given donor, the absorption maximum (λmax) was red‐shifted on changing the π linker from phenyl to 2,2′‐bithiophene, whilst the dyes that contained triphenylamine units displayed higher molar extinction coefficients (?) than their analogous phenothiazine‐based triphenylamine dyes, which led to good light‐harvesting properties in the triphenylamine‐based dyes. Electrochemical data for the dyes indicated that the triphenylamine‐based dyes possessed relatively low‐lying HOMOs, which could be beneficial for suppressing back electron transfer from the conduction band of TiO2 to the oxidized dyes, owing to facile regeneration of the oxidized dye by the electrolyte. The best performance in the DSSCs was observed for a dye that possessed a triphenylamine donor and 2,2′‐bithiophene π linkers. Electron impedance spectroscopy (EIS) studies revealed that the use of triphenylamine as the donor and phenyl or 2,2′‐bithiophene as the π linkers was beneficial for disrupting the dark current and charge‐recombination kinetics, which led to a long electron lifetime of the injected electrons in the conduction band of TiO2.  相似文献   

12.
We have synthesized and characterized four organic dyes ( 9 , 10 , H1 , H2 ) based on a 3,6‐disubstituted carbazole donor as sensitizers in dye‐sensitized solar cells. These dyes have high molar extinction coefficients and energy levels suitable for electron transfer from an electrolyte to nanocrystalline TiO2 particles. Under standard air mass 1.5 global (AM 1.5 G) solar irradiation, a device using dye H4 exhibits a short‐circuit current density (Jsc) of 13.7 mA cm?2, an open‐circuit voltage (Voc) of 0.68 V, a fill factor (FF) of 0.70, and a calculated efficiency of 6.52 %. This performance is comparable to that of a reference cell based on N719 (7.30 %) under the same conditions. After 1000 hours of visible‐light soaking at 60 °C, the overall efficiency remained at 95 % of the initial value.  相似文献   

13.
Three electron donor‐?? bridge‐electron acceptor (D‐π‐A) organic dyes bearing two carboxylic acid groups were applied to dye‐sensitized solar cells (DSSC) as sensitizers, in which one triphenylamine or modified triphenylamine and two rhodanine‐3‐acetic acid fragments act as D and A, respectively. It was found that the introduction of t‐butyl or methoxy group in the triphenylamine subunit could lead to more efficient photoinduced intramolecular charge transfer, thus improving the overall photoelectric conversion efficiency of the resultant DSSC. Under global AM 1.5 solar irradiation (73 mW·cm?2), the dye molecule based on methoxy‐substituted triphenylamine achieved the best photovoltaic performance: a short circuit photocurrent density (Jsc) of 12.63 mA·cm?2, an open circuit voltage (Voc) of 0.55 V, a fill factor (FF) of 0.62, corresponding to an overall efficiency (η) of 5.9%.  相似文献   

14.
Organic dyes with ethoxy‐substituted oligo‐phenylenevinylene as chromophores were synthesized for dye‐sensitized solar cells (DSSCs), and the detailed relationships between the dye structures, photophysical properties, electrochemical properties, and performances of DSSCs were described. The dye S3O showed broad IPCE spectra in the spectral range of 350–750 nm, and the dye S1P showed solar energy‐to‐electricity conversion efficiency (() of up to 4.23% under AM 1.5 irradiation (100 mW/cm2) in comparison with the reference Ru‐complex (N719 dye) with an η value of 5.90% under similar experimental conditions.  相似文献   

15.
Two novel main chain polymeric metal complexes containing 8‐hydroxyquinoline europium complexes and phenylethyl or fluorene units: 1,4‐Dioctyloxy‐2,5‐bis[2‐(8‐hydroxyquinoline)‐vinyl]‐benzene Eu(III) (3) and 2,7‐bis[2‐(8‐hydroxyquinoline)‐vinyl]‐9,9′‐diocthylfluorene Eu(III) (4) with donor–acceptor‐π‐conjugated structure (D‐π‐A) have been synthesized and investigated as dye sensitizers for dye‐sensitized solar cells dyes (DSSCs). They have been determined and studied by FT‐IR, TGA, DSC, GPC, Elemental analysis, UV–vis absorption spectroscopy, photoluminescence spectroscopy, cyclic voltammetry, and application in dye‐sensitized solar cells (DSSCs) as dye sensitizers. On the basis of optimized dye and molecular structure, they have shown solar‐to‐electricity conversion efficiency 2.25% for 3 (Jsc = 4.77 mA cm?2, Voc = 630 mV, FF = 0.75) and 3.04% for 4 (Jsc = 6.33 mA cm?2, Voc = 640 mV, FF = 0.75), under the illumination of AM1.5G, 100 mW/cm2. The IPCE of 3 and 4 are 30% and 46% at 400 nm, respectively. Besides, they showed good stabilities with thermal decomposition temperatures at 280 °C and 225 °C, respectively, which are suitable for DSSCs. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1943–1951, 2010  相似文献   

16.
A series of new push–pull phenothiazine‐based dyes ( HL1 , HL2 , HL3 , HL4 ) featuring various π spacers (thiophene, 3‐hexylthiophene, 4‐hexyl‐2,2′‐bithiophene) and double acceptors/anchors have been synthesized, characterized, and used as sensitizers for dye‐sensitized solar cells (DSSCs). Among them, the best conversion efficiency (7.31 %) reaches approximately 99 % of the N719‐based (7.38 %) DSSCs fabricated and measured under similar conditions. The dyes with two anchors have more efficient interfacial charge generation and transport compared with their congeners with only single anchor. Incorporation of hexyl chains into the π‐conjugated spacer of these double‐anchoring dyes can efficiently suppress dye aggregation and reduce charge recombination.  相似文献   

17.
Two D ‐π‐A conjugated molecules, BzTCA and BzTMCA , were developed through facile synthetic approaches for dye‐sensitized solar cells. The investigation of the photophysical properties of BzTCA and BzTMCA both in dilute solutions and in thin films indicates that their absorption exhibits a wide coverage of the solar spectrum. The absorption features for BzTCA and BzTMCA commence at about 710 nm in solution, and at about 800 nm in the solid state. The absorption maxima (λmax) for both BzTCA and BzTMCA on TiO2 film are almost the same as those in dilute solution. Their HOMOs and LUMOs were found to partly overlap at the center of these dyes, which guarantees appreciable interactions between the donors and acceptors. The investigation of the performance of dye‐sensitized solar cells fabricated from BzTCA and BzTMCA indicated that the power‐conversion efficiencies are 6.04 % and 4.68 %, respectively, which could be comparable with the normal sensitizer N3. BzTMCA showed lower incident photon‐to‐electron conversion efficiency (IPCE) and Jsc values relative to BzTCA , which is probably because of the weaker driving force of dye regeneration and electron injection process of BzTMCA . The IPCE responsive area reached nearly 800 nm, which provides great potential for further improvement of the photocurrent density and power‐conversion efficiency. Our investigations demonstrate that both dyes BzTCA and BzTMCA could be promising candidates for dye‐sensitized solar cells.  相似文献   

18.
《化学:亚洲杂志》2017,12(20):2749-2762
A novel class of β‐functionalized push–pull zinc opp ‐dibenzoporphyrins were designed, synthesized, and utilized as sensitizers for dye‐sensitized solar cells. Spectral, electrochemical, and computational studies were systematically performed to evaluate their spectral coverage, redox behavior, and electronic structures. These porphyrins displayed much broader spectral coverage and more facile oxidation upon extension of the π conjugation. Free‐energy calculations and femtosecond transient absorption studies (charge injection rate in the range of 1011 s−1) suggested efficient charge injection from the excited singlet state of the porphyrin to the conduction band of TiO2. The power conversion efficiency (η ) of YH3 bearing acrylic acid linkers (η =5.9 %) was close to that of the best ruthenium dye N719 (η =7.4 %) under similar conditions. The superior photovoltaic performance of YH3 was attributed to its higher light‐harvesting ability and more favorable electron injection and collection, as supported by electrochemical impedance spectral studies. This work demonstrates the exceptional potential of benzoporphyrins as sensitizers for dye‐sensitized solar cells.  相似文献   

19.
A series of heteroleptic bis(tridentate) RuII complexes featuring N^C^N‐cyclometalating ligands is presented. The 1,2,3‐triazole‐containing tridentate ligands are readily functionalized with hydrophobic side chains by means of click chemistry and the corresponding cyclometalated RuII complexes are easily synthesized. The performance of these thiocyanate‐free complexes in a dye‐sensitized solar cell was tested and a power conversion efficiency (PCE) of up to 4.0 % (Jsc=8.1 mA cm?2, Voc=0.66 V, FF=0.70) was achieved, while the black dye ((NBu4)3[Ru(Htctpy)(NCS)3]; Htctpy=2,2′:6′,2′′‐terpyridine‐4′‐carboxylic acid‐4,4′′‐dicarboxylate) showed 5.2 % (Jsc=10.7 mA cm?2, Voc=0.69 V, FF=0.69) under comparable conditions. When co‐adsorbed with chenodeoxycholic acid, the PCE of the best cyclometalated dye could be improved to 4.5 % (Jsc=9.4 mA cm?2, Voc=0.65 V, FF=0.70). The PCEs correlate well with the light‐harvesting capabilities of the dyes, while a comparable incident photon‐to‐current efficiency was achieved with the cyclometalated dye and the black dye. Regeneration appeared to be efficient in the parent dye, despite the high energy of the highest occupied molecular orbital. The device performance was investigated in more detail by electrochemical impedance spectroscopy. Ultimately, a promising RuII sensitizer platform is presented that features a highly functionalizable “click”‐derived cyclometalating ligand.  相似文献   

20.
A series of porphyrin sensitizers that featured two electron‐donating groups and dual anchoring groups that were connected through a porphine π‐bridging unit have been synthesized and successfully applied in dye‐sensitized solar cells (DSSCs). The presence of electron‐donating groups had a significant influence on their spectroscopic, electrochemical, and photovoltaic properties. Overall, the dual anchoring groups gave tunable electronic properties and stronger attachment to TiO2. These new dyes were readily synthesized in a minimum number of steps in gram‐scale quantities. Optical and electrochemical data confirmed the advantages of these dyes for use as sensitizers in DSSCs. Porphyrins with electron‐donating amino moieties provided improved charge separation and better charge‐injection efficiencies for the studied dual‐push–pull dyes. Attenuated total reflectance–Fourier‐transform infrared (ATR‐FTIR) and X‐ray photoelectron spectroscopy of the porphyrin dyes on TiO2 suggest that both p‐carboxyphenyl groups are attached onto TiO2, thereby resulting in strong attachment. Among these dyes, cis-Zn2BC2A , with two electron‐donating 3,6‐ditertbutyl‐phenyl‐carbazole groups and dual‐anchoring p‐carboxyphenyl groups, showed the highest efficiency of 4.07 %, with JSC=9.81 mA cm?2, VOC=0.63 V, and FF=66 %. Our results also indicated a better photostability of the studied dual‐anchored sensitizers compared to their mono‐anchored analogues under identical conditions. These results provide insight into the developments of a new generation of high‐efficiency and thermally stable porphyrin sensitizers.  相似文献   

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