Browsing by Author "Odobel, F."

Now showing 1 - 4 of 4

Exploring the application of new carbazole based dyes as effective p-type photosensitizers in dye-sensitized solar cells
(2017) Naik, P.; Planchat, A.; Pellegrin, Y.; Odobel, F.; Vasudeva, Adhikari, A.
Herein, we report the design and the synthesis of three new D-A type metal-free carbazole based dyes (C1 3) as effective photosensitizers for p-type DSSCs. In this new design, the electron rich carboxy substituted carbazole unit has been attached to three different electron withdrawing species, viz. N,N-dimethyl barbituric acid, N,N-diethyl thiobarbituric acid and N-ethyl rhodanine. They were well-characterized by spectral, photophysical and electrochemical analyses. Further, their optical and electrochemical parameters along with molecular geometries, optimized from DFT have been employed to apprehend the effect of structures of C1 3 on their photovoltaic performances. Further, the photovoltaic performance of C1 3 was determined along with the standard dye P1 and their PCE values were found to be in the order of P1 (0.047%) > C2 (0.040%) > C1 (0.016%) > C3 (0.001%). Interestingly, the NiO based p-type DSSC fabricated with C2 carrying electron withdrawing N,N-diethyl thiobarbituric acid displayed VOC as 59 4 mV and FF as 29 1%, which are higher than that of benchmark reference P1. This is attributed to the highest light harvesting ability, the greatest regeneration driving force and the lowest interfacial charge recombination of C2 among the tested dyes. Conclusively, the results showcase the potential of carbazole based D-A type sensitizers in the development of efficient p-type DSSCs. 2017 Elsevier Ltd
Exploring the application of new carbazole based dyes as effective p-type photosensitizers in dye-sensitized solar cells
(Elsevier Ltd, 2017) Naik, P.; Planchat, A.; Pellegrin, Y.; Odobel, F.; Vasudeva Adhikari, A.V.
Herein, we report the design and the synthesis of three new D-A type metal-free carbazole based dyes (C1–3) as effective photosensitizers for p-type DSSCs. In this new design, the electron rich carboxy substituted carbazole unit has been attached to three different electron withdrawing species, viz. N,N-dimethyl barbituric acid, N,N-diethyl thiobarbituric acid and N-ethyl rhodanine. They were well-characterized by spectral, photophysical and electrochemical analyses. Further, their optical and electrochemical parameters along with molecular geometries, optimized from DFT have been employed to apprehend the effect of structures of C1–3 on their photovoltaic performances. Further, the photovoltaic performance of C1–3 was determined along with the standard dye P1 and their PCE values were found to be in the order of P1 (0.047%) > C2 (0.040%) > C1 (0.016%) > C3 (0.001%). Interestingly, the NiO based p-type DSSC fabricated with C2 carrying electron withdrawing N,N-diethyl thiobarbituric acid displayed VOC as 59 ± 4 mV and FF as 29 ± 1%, which are higher than that of benchmark reference P1. This is attributed to the highest light harvesting ability, the greatest regeneration driving force and the lowest interfacial charge recombination of C2 among the tested dyes. Conclusively, the results showcase the potential of carbazole based D-A type sensitizers in the development of efficient p-type DSSCs. © 2017 Elsevier Ltd
New Carbazole-Based Sensitizers for p-Type DSSCs: Impact of the Position of Acceptor Units on Device Performance
(American Chemical Society, 2022) Keremane, K.S.; Pellegrin, Y.; Planchat, A.; Jacquemin, D.; Odobel, F.; Vasudeva Adhikari, A.V.
We report the design, synthesis, and characterization of two new carbazole-based organic dyes PC1-2as potential sensitizers for NiO-based p-type dye-sensitized solar cells (p-DSSCs). The D-A-π-A' configured PC1dye comprises a thienyl unit as a π-spacer and a malononitrile as an end-capping acceptor unit, whereas in PC2the cyanovinylene group serves as an acceptor unit and a thienyl group acts as a donor unit in a D-A-D configuration. These molecules achieved excellent solubility due to their long-branched alkyl chains. The current work encompasses their structural, photophysical, thermal, electrochemical, theoretical, and photoelectrochemical studies, establishing structure-property relationships. PC1-2exhibit λabsand λemiin the range of 389-404 and 448-515 nm, respectively, with a band gap in the range of 2.88-2.92 eV. Electrochemical studies confirm the feasibility of electron injection, regeneration, and recombination. The introduction of an additional electron-withdrawing group (cyanovinylene group) on the dye PC1skeleton endows it with a higher dye loading capacity, high hole injection, and a strengthened intramolecular charge transfer (ICT) effect, resulting in a redshifted ICT absorption with a higher molar extinction coefficient. Among the two new dyes, the device based on PC1achieved the highest power conversion efficiency (PCE) of 0.027% with a short-circuit current density (JSC) of 1.29 mA·cm-2, open-circuit voltage (VOC) of 67 mV, and fill factor (FF) of 31%, whereas the device with dye PC2performed less efficiently (PCE: 0.018%, JSC: 0.92 mA·cm-2, VOC: 68 mV, and FF: 30%). Conclusively, the study provides insights into the intricacies involved in the structural modification of carbazole-based p-type dyads for the development of highly efficient DSSCs. © 2022 American Chemical Society. All rights reserved.
Push-Pull Phenoxazine-Based Sensitizers for p-Type DSSCs: Effect of Acceptor Units on Photovoltaic Performance
(John Wiley and Sons Inc, 2022) Keremane, K.S.; Planchat, A.; Pellegrin, Y.; Jacquemin, D.; Odobel, F.; Vasudeva Adhikari, A.
Finding new efficient p-type sensitizers for NiO photocathodes is a great challenge for the development of promising low-cost tandem dye-sensitized solar cells (DSSCs). Now, the focus of researchers investigating these cells has been to create high-performance p-type systems. With this intention, herein, the design and synthesis of six new phenoxazine-based donor–acceptor (D–A)-configured organic dyes PO1–6 was reported, comprising different acceptor moieties specially designed for the sensitization of mesoporous p-type semiconductor NiO for the construction of p-type DSSCs (p-DSSCs). This work includes structural, photophysical, thermal, electrochemical, theoretical, and photoelectrochemical studies of these dyes, including evaluation of their structure-property relationships. The optical studies revealed that PO1–6 displayed adequate absorption and emission features in the range of 480–550 and 560–650 nm, respectively, with a bandgap in the order of 2.05–2.40 eV, and their thermodynamic parameters favored an efficient interfacial charge transfer involving NiO. Among the six new dyes, the device based on sensitizer PO2 carrying electron-withdrawing 1,3-diethyl-2-thiobarbituric acid achieved the highest power conversion efficiency of 0.031 % (short-circuit current density=0.89 mA cm−2, open-circuit voltage=101 mV, and fill factor=35 %). Conclusively, the study furnishes an understanding of the intricacies involved in the structural modification of phenoxazine-based sensitizers to further ameliorate the performance of the p-type DSSCs. © 2022 Wiley-VCH GmbH.