Synthesis and spectroscopic properties of a novel perylenediimide derivative

A novel symmetric 3,4,9,10-perylenetetracarboxylic acid derivative (PDI1) dye based on thiophene donor group was synthesized and characterized by FT-IR and 1H NMR. Cyclic Voltammetry analysis is performed to determine the energy levels of the perylene derivative. Optical characteristics were determined by visible absorption and fluorescence emission spectra. Spectral behavior and fluorescence quantum yield of PDI1 have been measured in different solvents. The dye exhibits high fluorescence quantum yield ( Φf: 0.94-0.99). But the quantum yield PDI1 is very low in the n-butanol solution ( Φf: 0.12). The photophysical properties have important implications for use in a variety of electroactive and photovoltaic applications. A photovoltaic device was fabricated with PDI1 as transporting material. The conversion efficiency for DSSC sensitized by PDI1 is 0.0065%. PDI1 exhibits electrochromic behavior by switching between neutral (red) and oxidized (blue) states. Electron transfer capacity of PDI to the TiO2 was investigated by incorporation of dye as sensitizer in dye sensitized solar cell (DSSC). Soluble dye molecules are very important to prepare dye sensitized solar cell. Solubility was increased with thiophene group

Synthesis and determination of fluorescence properties of new soluble diketopyrrolopyrrole type photosensitizers

Four organic small molecules bearing phenyl diketopyrrolopyrrole (DPP) unit as the main acceptor group and indole as the main thermal group with soluble units, coded as DPP3(a-b) and DPP4(a-b), were synthesized and their optical/electrochemical properties were investigated. Intense visible absorption bands around 480 nm were assigned to the DPP main core, as well as bands around 600 nm were attributed to the formation of charge-transfer complex between the electron-rich indole units and electron-withdrawing DPP core in chloroform solution. All of the compounds were found to be fluorescent in solution and on thin films with emission wavelengths between 500 and 700 nm. The fluorescence decay kinetic measurements of these dyes were also studied. The synthesized compounds have electrochemical energy band gaps from 2.15 to 2.28 eV. Then, the potential usage of the final products in bulk heterojunction solar cells (BHJ-OSCs) were evaluated. © 2019 Elsevier B.V

Conformational control of morphology for perylene diimide dimer as electron transporting material at perovskite surface

Synthesis of core-twisted perylene diimide (PDI) dimers attached with thiophene linkers (PDI-NHR-Th(1–4)) and their electron transporting ability at perovskite surface were studied. Synthesized dyes showed a high-lying lowest unoccupied molecular orbital (LUMO) energy levels between –3.68 and –3.71 eV, which were compatible with the conduction band of CH3NH3PbI2Br (–3.60 eV). Herein, we have investigated the role of the different substituted positions of PDI monomers to thiophene linkage from its (2,5)-, (3,4)-, (2,4)-, or (2,3)-positions in modulating the morphology of PDI dimer, aggregation behavior for charge transfer properties, optical shifts in ground and excited states, and recombination resistances at the interfaces of p-i-n devices. Conformational changes of PDI dimers attaching to different positions of thiophene linkers are found to affect not only photopysical dynamics of excited states of the dyes, but also charge transport kinetics at the perovskite interfaces, changing the photovoltaic performance. © 2023 Elsevier B.V.Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TÜBİTAK: 118Z948This study was financed by the Scientific and Technological Research Council of Turkey with the project number of 118Z948. We also thank to Ege University for the support of the use of Gaussian 09W program for theoretical DFT calculations

Indigo-Based Acceptor Type Small Molecules: Synthesis, Electrochemical and Optoelectronic Characterizations

In this paper, we report design and synthesis of novel low bandgap small molecules, indigo-benzimidazole (Tyr-3) and indigo-schiff base (Tyr-4) type acceptors. In these structures, tert-butoxycarbonyl (t-BOC) group has been attached to indigo nitrogen atom in order to increase the solubility. UV-vis absorption spectra of Tyr-3 and Tyr-4 dyes exhibit wide absorption bands ranging from 350 to 600 nm, indicating the relatively low bandgap giving around 2.07 eV for each. Excitation of both Tyr-3 and Tyr-4 dyes at 485 nm displays characteristic emission features of indigo moiety and also intramolecular charge transfer complex (ICT) related with their subunits. Besides increasing fluorescence quantum yields as compared to model compound, biexponential decay times for fluorescence life times were also obtained for Tyr-3 and Tyr-4 dyes. Their appropriate energy levels along with low HOMO levels are desired for light harvesting acceptors for organic solar cells when blended with poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2′,1′,3′-benzothiadiazole] (PCDTBT) as donor polymer. Photovoltaic behavior of the synthesized dyes were examined in bulk heterojunction concept and achieved photovoltaic conversion efficiencies were discussed. © 2018, Springer Science+Business Media, LLC, part of Springer Nature

Double connector to TiO2 surface in small molecule triphenyl amine dyes for DSSC applications

Two novel dyes 3a and 3b named triphenylamine groups containing donor–acceptor structural units have been explored to be used in dye sensitized solar cells as organic sensitizers. The absorption bands of the dyes were extended up to ~ 550 nm with visible absorption maxima at 408–430 nm and optical band gaps of 2.44–2.47 eV. Compared to the methoxyphenyl-substituted dye, the introduction of triisopropylphenyl group instead of that increased fluorescence quantum yields and exhibited red-shift emission in chloroform. We have investigated the photovoltaic properties of DSSCs based on these metal free organic dyes. It has been found that the power conversion efficiency of DSSCs sensitized with methoxyphenyl based triphenylamine dye is higher than that for sensitized with triisopropylphenyl derivative. © 2019, Springer Science+Business Media, LLC, part of Springer Nature

Comparison of the Optoelectronic Performance of Neutral and Cationic Forms of Riboflavin

The riboflavin dye 2,3,4,5-tetra-O-acetyl-1-[3-(6-bromohexyl)-7,8-dimethyl-2,4-dioxo-3,4-dihydrobenzo[g]pteridin-10(2H)-yl]-1-deoxypentitol and its pyridinium salt were synthesized, and studied by absorption and fluorescence spectroscopy in solutions and on thin film states. The first absorption band of riboflavin-pyridinium salt derivative is red-shifted by 10 nm compared to neutral one on film. Cationic riboflavin derivative shows significant wavelength changes on its fluorescence emission spectrum in the excited state depending on the solvent polarity and the electronic environment. The fluorescence quantum yields of cationic riboflavin gave much higher values as compared to that of its neutral form. The fluorescence lifetimes were found to be in the range of 5.5–6.6 ns with mono − exponential behavior. These dyes possess low-lying HOMO energy levels which are suitable to be able to inject holes to donor polymers so that they can be used as acceptor component in the active layer of bulk heterojunction solar cells (BHJ-SCs). Photovoltaic responses are reported for P3HT:riboflavin active layer wherein the synthesized dyes are used as acceptor component. Also, neutral riboflavin shows greater electron mobility value of 1.3 × 10−3 cm2/V∙s compared to its cationic derivative. © 2017, Springer Science+Business Media, LLC