scholarly journals Tuning the Acceptor Unit of Push–Pull Porphyrazines for Dye-Sensitized Solar Cells

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2129
Author(s):  
Diana-Paola Medina ◽  
Javier Fernández-Ariza ◽  
Maxence Urbani ◽  
Frédéric Sauvage ◽  
Tomás Torres ◽  
...  

A family of four push–pull porphyrazines of A3B type, where each unit A contains two peripheral propyl chains and the unit B is endowed with a carboxylic acid, were prepared. The carboxylic acid was attached to the b-position of the pyrrolic unit, either directly (Pz 10), or through cyanovinyl (Pz 11) and phenyl (Pz 7) groups. The fourth Pz (14) consisted in a pyrazinoporphyrazine wherein the dinitrogenated heterocycle provided intrinsic donor–acceptor character to the macrocycle and contained a carboxyphenyl substituent. The direct attachment of the carboxylic acid functions and their linkers to the porphyrazine core produces stronger perturbation on the electronic properties of the macrocycle, with respect to their connection through fused benzene or pyrazine rings in TT112 and 14, respectively. The HOMO and LUMO energies of the Pzs, which were estimated with DFT calculations, show little variation within the series, except upon introduction of the cyanovinyl spacer, which produces a decrease in both frontier orbital energetic levels. This effective interaction of cyanovinyl substitution with the macrocycle is also evidenced in UV/Vis spectroscopy, where a large splitting of the Q-band indicates strong desymmetrization of the Pz. The performance of the four Pzs as photosensitizers in DSSCs were also investigated.

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Reda M. El-Shishtawy ◽  
Shaaban A. Elroby ◽  
Abdullah M. Asiri ◽  
Rifaat H. Hilal

In an effort to provide, assess, and evaluate a theoretical approach which enables designing efficient donor-acceptor dye systems, the electronic structure and optical properties of pyran-squaraine as donor-acceptor dyes used in dye-sensitized solar cells were investigated. Ground state properties have been computed at the B3LYP/6-31+G**level of theory. The long-range corrected density functionals CAM-B3LYP, PBEPBE, PBE1PBE (PBE0), and TPSSH with 6-311++G**were employed to examine absorption properties of the studied dyes. In an extensive comparison between experimental results and ab initio benchmark calculations, the TPSSH functional with 6-311++G**basis set was found to be the most appropriate in describing the electronic properties for the studied pyran and squaraine dyes. Natural transition orbitals (NTO), frontier molecular orbitals (FMO), LUMO, HOMO, and energy gaps, of these dyes, have been analyzed to show their effect on the process of electron injection and dye regeneration. Interaction between HOMO and LUMO of pyran and squaraine dyes was investigated to understand the recombination process and charge-transfer process involving these dyes. Additionally, we performed natural bond orbital (NBO) analysis to investigate the role of charge delocalization and hyperconjugative interactions in the stability of the molecule.


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.


2013 ◽  
Vol 8 (9) ◽  
pp. 2144-2153 ◽  
Author(s):  
Ram B. Ambre ◽  
Gao-Fong Chang ◽  
Manoj R. Zanwar ◽  
Ching-Fa Yao ◽  
Eric Wei-Guang Diau ◽  
...  

2021 ◽  
Author(s):  
Kevser Harmandar ◽  
Kevin Granados-Tavera ◽  
Merve Keskin ◽  
Mehmet Nebioğlu ◽  
İlkay Şişman ◽  
...  

An asymmetric zinc phthalocyanine dye (KH1) bearing three 2,6-di-tert-butyl-4-methylphenoxy donor groups and carboxylic acid anchoring group was synthesized as a sensitizer for dye-sensitized solar cells (DSSCs). The DSSC based on...


2019 ◽  
Vol 23 (04n05) ◽  
pp. 599-610 ◽  
Author(s):  
Siddhartha Kumar ◽  
Whitney Webre ◽  
Jacob Schaffner ◽  
Sheikh M. S. Islam ◽  
Francis D’Souza ◽  
...  

The first example of A2B2 tetrabenzoporphyrin (KW-4) was synthesized, characterized and evaluated as a sensitizer for dye-sensitized solar cells. UV-vis and fluorescence spectroscopy revealed red-shifted and broadened absorption spectra of A2B2 tetrabenzoporphyrin as compared with its A2 dibenzo- and A2B2 dibenzoporphyrin analogues, which is a desired feature of dyes for dye-sensitized solar cells. DFT calculations also indicate favorable electron density distribution on the HOMO and LUMO of KW-4. However, the power conversion efficiency of the solar cell based on tetrabenzoporphyrin KW-4 displayed inferior performance than that of the solar cell based on A2 dibenzoporphyrin KW-2. The lower performance of the KW-4 cell was ascribed to two factors: the low lying LUMO energy level leading to less efficient electron injection and the “flat geometry” of the dye on TiO2surface facilitating charge recombination and decreasing dye loading. The investigation of anchoring group effect suggests that the acrylic acid group is a better anchoring group than pentadienyl carboxylic acid.


2012 ◽  
Vol 93 (1-3) ◽  
pp. 1488-1497 ◽  
Author(s):  
Hsuan-Chih Chu ◽  
Duryodhan Sahu ◽  
Ying-Chan Hsu ◽  
Harihara Padhy ◽  
Dhananjaya Patra ◽  
...  

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