Naphthalimide-phenothiazine based A’-π-D-π-A featured organic dyes for dye sensitized solar cell applications

Nagarajan, Bhanumathi; Dakshinamurthy, Athrey C.; Ramachandran, Elumalai; Sudakar, C.; Dhamodharan, R.

doi:10.1016/j.jphotochem.2020.112820

Cited by 26 publications

(14 citation statements)

References 53 publications

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“…The PTZ unit is an electron-rich tricyclic heteroarene with nonplanar butterfly structure, characterized by the presence of powerful electron-donor sulfur and nitrogen atoms . In the literature, the photophysical properties and the HOMO–LUMO energy levels of PTZ derivatives have been easily modulated by substitutions at the nitrogen and the 3,7-positions of the phenothiazine unit. , Our group has functionalized the 3,7-positions of the phenothiazine unit by using polycyclic aromatic hydrocarbons of increasing complexity or strong acceptors such as benzothiadiazole or tetracyanobutadiene. , In the literature, push–pull phenothiazine–naphthalimide systems have been successfully employed in some optoelectronic applications. − However, the research on varying the oxidation state of the sulfur atom (sulfides, sulfoxides, and sulfones) in the thiazine ring of phenothiazine is still very limited. − In this study, we have synthesized new naphthalimide and phenothiazine-based systems, in which we have changed the oxidation state of the sulfur atom on the thiazine ring to investigate its effect on the photonic properties of the obtained materials.…”

Section: Introductionmentioning

confidence: 99%

Tuning the Fluorescence and the Intramolecular Charge Transfer of Phenothiazine Dipolar and Quadrupolar Derivatives by Oxygen Functionalization

et al. 2021

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A series of new naphthalimide and phenothiazine-based push−pull systems (NPI-PTZ1−5), in which we structurally modulate the oxidation state of the sulfur atom in the thiazine ring, i.e., S(II), S(IV), and S(VI), was designed and synthesized by the Pd-catalyzed Sonogashira cross-coupling reaction. The effect of the sulfur oxidation state on the spectral, photophysical, and electrochemical properties was investigated. The steady-state absorption and emission results show that oxygen functionalization greatly improves the optical (absorption coefficient and fluorescence efficiency) and nonlinear optical (hyperpolarizability) features. The cyclic voltammetry experiments and the quantum mechanical calculations suggest that phenothiazine is a stronger electron donor unit relative to phenothiazine-5-oxide and phenothiazine-5,5-dioxide, while the naphthalimide is a strong electron acceptor in all cases. The advanced ultrafast spectroscopic measurements, transient absorption, and broadband fluorescence up conversion give insight into the mechanism of photoinduced intramolecular charge transfer. A planar intramolecular charge transfer (PICT) and highly fluorescent excited state are populated for the oxygen-functionalized molecules NPI-PTZ2,3 and NPI-PTZ5; on the other hand, a twisted intramolecular charge transfer (TICT) state is produced upon photoexcitation of the oxygen-free derivatives NPI-PTZ1 and NPI-PTZ4, with the fluorescence being thus significantly quenched. These results prove oxygen functionalization as a new effective synthetic strategy to tailor the photophysics of phenothiazine-based organic materials for different optoelectronic applications. While oxygen-functionalized compounds are highly fluorescent and promising active materials for current-to-light conversion in organic light-emitting diode devices, oxygen-free systems show very efficient photoinduced ICT and may be employed for light-to-current conversion in organic photovoltaics.

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Section: Introductionmentioning

confidence: 99%

Tuning the Fluorescence and the Intramolecular Charge Transfer of Phenothiazine Dipolar and Quadrupolar Derivatives by Oxygen Functionalization

et al. 2021

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“…Moreover, the substituents at the nitrogen atom of phenothiazine can enhance the charge separation . Considering the electron acceptor unit, which usually acts as the anchoring group of dye to the semiconductor oxide surface, cyanoacrylic acid is the most commonly applied group. − Thus, phenothiazine derivatives with cyanoacrylic acids as anchoring units are widely spread in the literature as dyes for DSSCs. ,,, Recently, we reported two novel organic dyes with D/A−π–D−π–A structures based on the phenothiazine framework . The donor phenothiazine unit was the extended system’s central core connected via ethylene linkers with end-capped donor or acceptor units, and cyanoacrylic acid acted as the anchoring group.…”

Section: Introductionmentioning

confidence: 99%

New D−π–D−π–A Systems Based on Phenothiazine Derivatives with Imidazole Structures for Photovoltaics

et al. 2022

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Two new compounds with an N-octyl phenothiazine core substituted at C(7) position via a triple bond with imidazole-containing butyl or dodecyl chains bearing on the opposite side at the C(7) cyanoacrylate moiety were synthesized. Photophysical and electrochemical studies were performed to evaluate the possibility of applying them in the dye-sensitized solar cells (DSSCs). The investigations were supported by density functional theory and time-dependent DFT. The synthesized dyes showed a similar absorption profile ranging from 250 to 600 nm in solvents and a high value of light-harvesting efficiency of about 0.8. It was found that its photoluminescence quantum yield was solvent-dependent, and the highest value (about 50%) was reached in DMF solution. Electrochemical measurements revealed that both compounds showed electron injection ability from the LUMO of the molecule to the TiO 2 conduction band and the possibility of regeneration by an electrolyte. DSSCs sensitized with the phenothiazine derivatives differing in TiO 2 thickness and the type of electrolyte (iodide and cobalt) were prepared. Additionally, transient absorption measurements in solution and solar cells were carried out to study excited-state properties and electron transfer dynamics. The influence of the hydrophobic hydrocarbon chain length of the imidazole unit in these dyes as well as TiO 2 thickness and the type of electrolyte on the device performance was observed. DSSCs sensitized with phenothiazine with dodecyl chains showed higher photocurrent, open-circuit voltage, and finally the power conversion efficiency, regardless of TiO 2 thickness.

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“…Nagarajan et al 142 reported two PTZ‐based dyes ( 237 and 238 ) having naphthalimide as an auxiliary acceptor. 237 and 238 displayed efficiency of 4.91% and 4.57%, respectively.…”

Section: Recent Developments In Ptz‐based Dyesmentioning

confidence: 99%

Recent developments in metal‐free organic sensitizers derived from carbazole, triphenylamine, and phenothiazine for dye‐sensitized solar cells

et al. 2021

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Summary In the present context of increasing population, renewable and sustainable energy alternatives are very much essential to satisfy the necessities of the world. To satisfy this growing demand, scientists are prioritizing the production of cost‐effective and high‐performance clean energy appliances. Dye‐sensitized solar cells (DSSCs) are one such material that is at the forefront of modern solar cell technologies. Being one of the main components of DSSCs, metal‐free organic dyes play a crucial role in light processing and electron injection. In recent times, carbazole (CZ)‐, triphenylamine (TPA)‐, and phenothiazine (PTZ)‐based derivatives have been identified as suitable alternatives to Ru(II) polypyridyl complexes because they are easy to synthesize and exhibit excellent thermal and electronic properties. This review focuses largely on the latest developments in the use of monoanchored and multianchored CZ, TPA, and PTZ scaffolds for DSSC applications and focuses especially on the correlation between molecular design and photovoltaic performance. The physical properties of devices can be adjusted through the sensitizer's strategic design that helps to improve the performance of the devices. We tabulated the photovoltaic parameters corresponding to all dyes presented in this review. Also, applications of additives are presented after the systematic review on CZ‐, TPA‐, and PTZ‐based dyes.

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Naphthalimide-phenothiazine based A’-π-D-π-A featured organic dyes for dye sensitized solar cell applications

Cited by 26 publications

References 53 publications

Tuning the Fluorescence and the Intramolecular Charge Transfer of Phenothiazine Dipolar and Quadrupolar Derivatives by Oxygen Functionalization

Tuning the Fluorescence and the Intramolecular Charge Transfer of Phenothiazine Dipolar and Quadrupolar Derivatives by Oxygen Functionalization

New D−π–D−π–A Systems Based on Phenothiazine Derivatives with Imidazole Structures for Photovoltaics

Recent developments in metal‐free organic sensitizers derived from carbazole, triphenylamine, and phenothiazine for dye‐sensitized solar cells

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