scholarly journals Effect of Auxiliary Donors on 3,8-Phenothiazine Dyes for Dye-Sensitized Solar Cells

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4485
Author(s):  
Audun Formo Buene ◽  
Mats Christensen ◽  
Bård Helge Hoff

Phenothiazines are one of the more common dye scaffolds for dye-sensitized solar cells. However, these sensitizers are exclusively based on a 3,7-substitution pattern. Herein, we have synthesized and characterized novel 3,8-substituted phenothiazine dyes in order to evaluate the effect of auxiliary donor groups on the performance of this new dye class. The power conversion efficiency increased by 7%–10% upon insertion of an auxiliary donor in position 8 of the phenothiazine, but the structure of the auxiliary donor (phenyl, naphthyl, pyrene) had a low impact when electrodes were stained with chenodeoxycholic acid (CDCA) additive. In the absence of CDCA, the highest power conversion efficiency was seen for the phenyl-based sensitizer attributed to a higher quality dye-monolayer. By comparing the novel dyes to their previously reported 3,7- analogues, only subtle differences were seen in photophysical, electrochemical, and performance measurements. The most notable difference between the two geometries is a lowering of the oxidation potentials of the 3,8-dyes by 40–50 mV compared to the 3,7-analogues. The best auxiliary donor for the 3,8-phenothiazine dyes was found to be pyrenyl, with the best device delivering a power conversion efficiency of 6.23% (99 mW cm−2, 10 eq. CDCA, JSC = 10.20 mA cm−2, VOC = 791 mV, and FF = 0.765).

2021 ◽  
Vol 11 (3) ◽  
pp. 674-678
Author(s):  
Shibing Zou ◽  
Lingting Song ◽  
Junhong Duan ◽  
Le Huang ◽  
Weiqing Liu ◽  
...  

2015 ◽  
Vol 19 (01-03) ◽  
pp. 175-191 ◽  
Author(s):  
Ganesh D. Sharma ◽  
Galateia E. Zervaki ◽  
Kalliopi Ladomenou ◽  
Emmanuel N. Koukaras ◽  
Panagiotis P. Angaridis ◽  
...  

Two porphyrin dyads with the donor-π-acceptor molecular architecture, namely ( ZnP )-[triazine-gly]-( H 2 PCOOH ) and ( ZnP )-[triazine-Npip]-( H 2 PCOOH ), which consist of a zinc-metalated porphyrin unit and a free-base porphyrin unit covalently linked at their peripheries to a central triazine group, substituted either by a glycine in the former or a N-piperidine group in the latter, have been synthesized via consecutive amination substitution reactions of cyanuric chloride. The UV-vis absorption spectra and cyclic-voltammetry measurements of the two dyads, as well as theoretical calculations based on Density Functional Theory, suggest that they have suitable frontier orbital energy levels for use as sensitizers in dye-sensitized solar cells. Dye-sensitized solar cells based on ( ZnP )-[triazine-gly]-( H 2 PCOOH ) and ( ZnP )-[triazine-Npip]-( H 2 PCOOH ) have been fabricated, and they were found to exhibit power conversion efficiency values of 5.44 and 4.15%, respectively. Photovoltaic measurements (J–V curves) and incident photon to current conversion efficiency spectra of the two solar cells suggest that the higher power conversion efficiency value of the former solar cell is a result of its enhanced short circuit current, open circuit voltage, and fill factor values, as well as higher dye loading. This is ascribed to the existence of two carboxylic acid anchoring groups in ( ZnP )-[triazine-gly]-( H 2 PCOOH ), compared to one carboxylic acid group in ( ZnP )-[triazine-Npip]-( H 2 PCOOH ), which leads to a more effective binding onto the TiO 2 photoanode. Electrochemical impedance spectra show evidence that the ( ZnP )-[triazine-gly]-( H 2 PCOOH ) based solar cell exhibits a longer electron lifetime and more effective suppression of charge recombination reactions between the injected electrons and electrolyte.


RSC Advances ◽  
2016 ◽  
Vol 6 (84) ◽  
pp. 81184-81190 ◽  
Author(s):  
Qingbiao Qi ◽  
Jing Zhang ◽  
Soumyajit Das ◽  
Wangdong Zeng ◽  
Jie Luo ◽  
...  

Three push–pull type, alkoxy-wrapped N-annulated perylene based sensitizers were synthesized and power conversion efficiency up to 8.38% was achieved.


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