| 1. |
- Chen, Yingying, et al.
(författare)
-
Fluorenyl Indoline as an Efficient Electron Donor for Concerted Companion Dyes: Enhanced Light-Harvesting and Photocurrent
- 2021
-
Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 13:42, s. 49828-49839
-
Tidskriftsartikel (refereegranskat)abstract
- Concerted companion dyes (CC dyes) like XW61 have been demonstrated to be an effective platform for developing efficient DSSCs. However, the moderated phenothiazine-based electron donor in XW61 results in unsatisfactory J(sc). To address this problem, a stronger fluorenyl indoline-based electron donor has been used to construct porphyrin dye XW68 and organic dyes Y1-Y2. The stronger electron-donating character of the fluorenyl indoline unit leads to an enhanced J(sc) value (20.48 mA.cm(-2)) for the individual dye XW68. On this basis, CC dyes XW69-XW70-C8 have been designed and synthesized by combining the frameworks of Y1 and Y2 with XW68. The complementary absorption characters of the porphyrin and the organic dye moieties lead to panchromatic absorption with a strong light-harvesting capability from 350 to 700 nm and the onset wavelength extended to ca. 840 nm in the IPCE curves. As a result, excellent J(sc) values have been achieved (>22 mA.cm(-2)). In addition to the advantages of high J(sc), bulky octyl groups have been introduced into the donor of XW70-C8 to reduce dye aggregation and suppress charge recombination. Finally, a highest PCE of 11.1% with a satisfactory J(sc) (22.25 mA.cm(-2)) and an enhanced V-oc (750 mV) has been achieved upon coadsorption of XW70-C8 with CDCA. In addition, the CC dye XW70-C8-based solar cells exhibit excellent long-term photostability. These results provide an effective method for rationally improving the photovoltaic behavior, especially the J(sc) of CC dyes, by introducing strong electron donor moieties with suitable substituents.
|
|
| 2. |
- Tang, Yunyu, et al.
(författare)
-
Porphyrins Containing a Triphenylamine Donor and up to Eight Alkoxy Chains for Dye-Sensitized Solar Cells : A High Efficiency of 10.9%
- 2015
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 7:50, s. 27976-27985
-
Tidskriftsartikel (refereegranskat)abstract
- Porphyrins are promising DSSC sensitizers due to their structural similarity to chlorophylls as well as their tunable strong absorption. Herein, a novel D-pi-A porphyrin dye XW14 containing a strongly electron-donating triphenyl-amine moiety as the electron donor was designed and synthesized: To avoid undesirably decreased V-oc caused by dye aggregation effect, two methoxy or hexyloxy chains were introduced to the para positions of the triphenylamine moiety to afford XW15 and XW16, respectively. To further extend the absorption to a longer wavelength, a benzothiadiazole unit was introduced as an auxiliary acceptor to furnish XW17. Compared with XW14, the introduction of additional methoxy or hexyloxy groups in XW15 and XW16 red-shift the onset wavelengths from 760 to 780 and 790 nm, respectively. More impressively, XW17 has a more extended pi-conjugation framework, and thus, it exhibits a much broader IPCE spectrum with an extremely red-shifted onset wavelength Of 830 mu, resulting in the highest J(sc) (18.79 mA cm(-2)). On the other hand, the hexyloxy chains are favorable for suppressing the dye aggregation effect, and thus XW16 shows the highest V-oc 734 mV. As a result, XW16 and XW17 demonstrate photovoltaic efficiencies of 9,1 and 9.5%, respectively, higher than those of XW14 (8.6%) and XW15 (8.7%), and obviously higher than that of 7.94% for our previously reported dye, XW4. On the basis of optimized porphyrin dye XW17, we used a nonporphyrin dye with a high V-oc and strong absorption around 500 inn (WS-5) as the cosensitizer to improve the V-oc from 700 to 748 mV, with synergistical J(sc) enhancement from 18.79 to 20.30 mA cm(-2). Thus, the efficiency was dramatically enhanced to 10.9%, which is among the highest efficiencies obtained for the DSSCs based on traditional iodine electrolyte. In addition, the DSSCs based on XW17 + WS-5 exhibit good photostability, which is beneficial for practical applications.
|
|
| 3. |
- Tang, Yunyu, et al.
(författare)
-
Solar cells sensitized by porphyrin dyes containing a substituted carbazole donor with synergistically extended absorption and suppressed the dye aggregation
- 2020
-
Ingår i: Chinese Chemical Letters. - : Elsevier BV. - 1001-8417 .- 1878-5964. ; 31:7, s. 1927-1930
-
Tidskriftsartikel (refereegranskat)abstract
- To achieve high power conversion efficiencies (PCEs), three porphyrin sensitizers have been synthesized and explored to simultaneously enhance the photocurrent (Jsc) and photovoltage (Voc). On basis of the XW4, a benzothiadiazole (BTD) unit has been introduced to afford XW57 with the aim to extend the absorption wavelength and enhance the light harvesting ability. As a result, a Jsc of 13.72 mA/cm2 has been obtained for XW57, higher than that of XW4. On this basis, XW58 has been prepared by modifying the carbazole-based donor with two bulky dihexyloxyphenyl groups, and the superior anti-aggregation character raises the Voc from 781 mV (XW4) to 844 mV. When both the BTD unit and the bulky groups are introduced to the acceptor and donor units, respectively, the resulting sensitizer XW59 exhibits a highest PCE value of 7.34% with synergistically enhanced Jsc of 13.19 mA/cm2 and Voc of 793 mV. These results provide further insight into developing high performance dye-sensitized solar cells
|
|
| 4. |
- Tang, Yunyu, et al.
(författare)
-
Solar cells sensitized with porphyrin dyes with a carbazole donor : The effects of an auxiliary benzothiadiazole acceptor and bulky substituents on the donor
- 2019
-
Ingår i: Dyes and pigments. - : ELSEVIER SCI LTD. - 0143-7208 .- 1873-3743. ; 171
-
Tidskriftsartikel (refereegranskat)abstract
- Three porphyrin sensitizers XW54-XW56 containing a carbazole donor have been designed and synthesized by introducing a benzothiadiazole (BTD) unit as the auxiliary electron acceptor to extend the absorption spectra and/or bulky dihexyloxyphenyl groups into the carbazole unit to suppress dye aggregation and improve the photovoltage (V-OC). The BTD unit incorporated in XW54 obviously broadens and red-shifts the absorption threshold to ca. 700 nm, as compared with that of 650 nm observed for XW1. Thus, XW54 exhibits a much broader monochromatic photon-to-electron conversion efficiency (IPCE) spectrum with an extremely red-shifted onset wavelength of 780 nm, resulting in a photocurrent density (J(SC)) of 11.60 mA cm(-2), higher than that of XW1. Unfortunately, the V-OC value was decreased owing to the more severe dye aggregation caused by the large conjugation framework induced by the presence of the BTD unit. As a result, XW54 shows an efficiency of 6.26%, slightly higher than that of 6.11% obtained for XW1. On the other hand, with the bulky dihexyloxyphenyl donor groups introduced to XW55, a highest V-OC, of 860 mV was achieved, which can be ascribed to the efficient prevention of charge recombination and suppression of dye aggregation. Thus, XW55-based cells exhibit an improved efficiency of 6.60%. On the basis of XW54 and XW55, two bulky dihexyloxyphenyl groups and a BTD unit were simultaneously introduced to XW56, affording a highest efficiency of 7.03%, with the J(SC )and V-OC, values of 12.5 mA cm(-2) and 785 mV, respectively. These results compose a novel approach for developing efficient dye-sensitized solar cells (DSSCs) by simultaneously introducing bulky dihexyloxyphenyl groups and a benzothiadiazole unit, which may synergistically broaden the absorption spectra and suppress the dye aggregation, resulting in improved photocurrent and photovoltage.
|
|
| 5. |
- Yang, Guosheng, et al.
(författare)
-
Efficient Solar Cells Based on Porphyrin Dyes with Flexible Chains Attached to the Auxiliary Benzothiadiazole Acceptor : Suppression of Dye Aggregation and the Effect of Distortion
- 2017
-
Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 9:42, s. 36875-36885
-
Tidskriftsartikel (refereegranskat)abstract
- Donor-pi-acceptor-type porphyrin dyes have been widely used for the fabrication of efficient dye-sensitized solar cells (DSSCs) owing to their strong absorption in the visible region and the ease of modifying their chemical structures and photovoltaic behavior. On the basis of our previously reported efficient porphyrin dye XW11, which contains a phenothiazine-based electron donor, a pi-extending ethynylene unit, and an auxiliary benzothiadiazole acceptor, we herein report the syntheses of novel porphyrin dyes XW26- XW28 by introducing one or two alkyl/alkoxy chains into the auxiliary acceptor. The introduced chains can effectively suppress dye aggregation. As a result, XW26 XW28 show excellent photovoltages of 700, 701, and 711 mV, respectively, obviously higher than 645 mV obtained for XW11. Nevertheless, the optimized structures of XW26 and XW27 exhibit severe distortion, showing large dihedral angles of 57.2(circle) and 44.0(circle), respectively, between the benzothiadiazole and benzoic acid units, resulting from the steric hindrance between the benzoic acid unit and the neighboring alkyl/alkoxy chain on the benzothiadiazole unit, and thus blue-shifted absorption, decreased photocurrents. and low efficiencies of 5.19% and 6.42% were observed for XW26 and XW27, respectively. Interestingly, XW26 exhibits a more blue -shifted absorption spectrum relative to XW27, indicating that the steric hindrance of the alkyl/alkoxy chains has a more pronounced effect than the electronic effect. Different from XW26 and XW27, XW28 contains only one alkyl chain neighboring the ethynylene unit, which does not induce obvious steric hindrance with the benzoic acid unit, and thus distortion of the molecule is not seriously aggravated compared with XW11. Hence, its absorption spectrum and photocurrent are similar to those of XW11. As a result, a higher efficiency of 9.12% was achieved for XW28 because of its suppressed dye aggregation and higher photovoltage. It is worth noting that a high efficiency of 10.14% was successfully achieved for XW28 upon coadsorption with CD CA, which is also higher than the corresponding efficiency obtained for XW11. These results provide a novel approach for developing efficient porphyrin dyes by introducing chains into the suitable position of the auxiliary benzothiadiazolyl moiety to suppress dye aggregation, without seriously aggravating distortion of the dye molecules.
|
|
| 6. |
- Zou, Jiazhi, et al.
(författare)
-
Porphyrins containing a tetraphenylethylene-substituted phenothiazine donor for fabricating efficient dye sensitized solar cells with high photovoltages
- 2022
-
Ingår i: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 10:3, s. 1320-1328
-
Tidskriftsartikel (refereegranskat)abstract
- With the aim to enhance the photovoltages and efficiencies of dye sensitized solar cells (DSSCs) based on porphyrin dyes, a dialkoxy-substituted highly twisted tetraphenylethylene (TPE) moiety has been introduced into the donor unit of a porphyrin dye to suppress dye aggregation and charge recombination. Thus, based on our previously reported porphyrin dye XW43, a dialkoxy-TPE moiety has been introduced into the phenothiazine donor to afford XW71. Compared with the diethyleneglycol substituent in XW43, the bulkier dialkoxy-TPE unit in XW71 is more beneficial for suppressing charge recombination. The alkoxy chains on the TPE moieties in XW71 are extended outward from the molecule and folded toward the porphyrin macrocycle, respectively, favorable for suppressing dye aggregation and charge recombination. As a result, the V-OC was dramatically improved from 0.750 V (XW43) to 0.765 V (XW71). On this basis, the substituents surrounding the porphyrin macrocycle have been optimized to further improve the V-OC and the efficiencies. Thus, XW72 and XW73 have been synthesized by replacing the dodecyloxy moieties on the meso-phenyl substituents of XW71 with two diethyleneglycol (DEG) chains and double straps, respectively. As a result, XW72 and XW73 exhibit a gradually improved V-OC of 0.772 V and 0.777 V, respectively, and a high power conversion efficiency (PCE) of 11.0% has been achieved for XW73. Upon coadsorption and cosensitization, the efficiency can be further enhanced to an outstanding value of 12.3% for the XW73 + CDCA + XC3 system.
|
|
