Effect of molecular and electronic structure on the light harvesting properties of dye sensitizers

The systematic trends in structural and electronic properties of perylene diimide (PDI) derived dye molecules have been investigated by DFT calculations based on projector augmented wave (PAW) method including gradient corrected exchange-correlation effects. TDDFT calculations have been performed to study the visible absorbance activity of these complexes. The effect of different ligands and halogen atoms attached to PDI were studied to characterize the light harvesting properties. The atomic size and electronegativity of the halogen were observed to alter the relaxed molecular geometries which in turn influenced the electronic behavior of the dye molecules. Ground state molecular structure of isolated dye molecules studied in this work depends on both the halogen atom and the carboxylic acid groups. DFT calculations revealed that the carboxylic acid ligands did not play an important role in changing the HOMO-LUMO gap of the sensitizer. However, they serve as anchor between the PDI and substrate titania surface of the solar cell or photocatalyst. A commercially available dye-sensitizer, ruthenium bipyridine (RuBpy), was also studied for electronic and structural properties in order to make a comparison with PDI derivatives for light harvesting properties. Results of this work suggest that fluorinated, chlorinated, brominated, and iyodinated PDI compounds can be useful as sensitizers in solar cells and in artificial photosynthesis.Comment: Single pdf file, 14 pages with 7 figures and 4 table

Modulation of internal charge transfer (ICT) in a bay region hydroxylated perylenediimide (PDI) chromophore: a chromogenic chemosensor for pH

A novel perylenediimide derivative which has a bay region hydroxyl function behaves as a pH-sensitive dye. The deprotonation of the aryl-OH yields a green solution with a lambda(max) x of 692 nm and this deprotonated form has strong internal charge transfer characteristics. On reprotonation in acidic solutions, the typical PDI absorbance spectrum is restored. The experimentally determined pK(a) (7.45) is very close to physiological pH, therefore the most significant changes in color take place in the vicinity of this pH value

Characterization of 1,7-dibromo-N,N '-(bicyclohexyl)-3,4:9,10-perylendiimide Langmuir-Blodgett film for organic vapor sensing application

Conference and Exhibition on Science and Applications of Thin Films (SATF) -- SEP 15-19, 2014 -- Cesme, TURKEYWOS: 0003591666000241,7-Dibromo-N,N'-(bicyclohexyl)-3,4:9,10-perylendiimide material (FY3) was used as a sensor element in this work. Different number of LB thin film layer was deposited onto a gold-coated glass substrate to produce a thin film sensor element. Fabrication processes were monitored by surface plasmon resonance (SPR) technique. The experimental SPR data were fitted using the Winspall software to evaluate the film thickness and refractive index of this material. Values of the thickness and refractive index of LB films were determined as 0.54 +/- 0.01 nm for the thickness per monolayer, and 0.46 +/- 0.08 for the refractive index. LB thin film sensor element was exposed to chloroform, benzene, toluene and ethyl alcohol vapors. In-situ SPR measurements showed that the response of the FY3 LB film for saturated chloroform vapor is much larger than the other vapors with 4s recovery times and 5s response time. The photodetector response change, Delta I-rf was monitored when FY3 LB film was exposed to these organic vapors and the response of the FY3 LB film to chloroform was also the largest among organic vapors with the Delta I-rf value of 0.11 au. It can be proposed that this sensing element deposited onto gold-coated glass substrates has a good sensitivity and selectivity for saturated chloroform vapor. (C) 2015 Elsevier B.V. All rights reserved

Spun films of perylene diimide derivative for the detection of organic vapors with host–guest principle

The optical characterization and chemical vapor sensing properties of 1,7-dibromo-N,N?-(bicyclohexyl)-3,4:9,10-perylene diimide thin film against to organic vapors were discussed in this study by using spin coating, UV–Vis spectroscopy, atomic force microscopy, surface plasmon resonance (SPR) and Quartz Crystal Microbalance (QCM) techniques. The perylene diimide thin films were fabricated with a refractive index values from 1.55 to 1.60 and thicknesses in the range between 15.80 and 26.32 nm using different spin speeds from 1000 to 5000 rpm. In this study, perylene diimide thin film sensor was exposed to dichloromethane, chloroform, carbon tetrachloride, tetrahydrofuran and ethyl acetate vapors by using both SPR and QCM techniques. Also, the swelling behaviors of the perylene diimide thin films prepared at different spin speeds were investigated with respect to dichloromethane vapor at the room temperature by using SPR data. Diffusion coefficients were found to be 11.34 × 10?17 (1000 rpm), 2.56 × 10?17 (3000 rpm) and 0.38 × 10?17 cm2 s?1 (5000 rpm) for dichloromethane vapor by using the Fick’s law of diffusion. It might be proposed that perylene diimide thin film optical chemical sensor element has a good sensitivity and selectivity for the dichloromethane vapor at room temperature. © 2018, Springer Nature B.V.British Association for PsychopharmacologyAcknowledgements The authors would like to thank The Research Foundation of Usak University (BAP) for financial support of this work. Project no.: 2014/MF014

Optical Characterization of an N,N?-Dicyclohexyl-3,4:9,10-Perylene bis(Dicarboximide) Langmuir–Blodgett Film for the Determination of Volatile Organic Compounds

Langmuir–Blodgett thin-film fabrication and gas-sensing properties of a novel N,N?-dicyclohexyl-3,4:9,10-perylene bis(dicarboximide) material are reported. Surface plasmon resonance was used to study the deposition process. Fitted data were used to evaluate the refractive index and the thickness of the material. Thickness of a single layer and refractive index were determined to be 0.43 ± 0.04 nm and 1.52 ± 0.07, respectively. Responses of films to chloroform, benzene, and toluene were measured by surface plasmon resonance. Changes in reflectivity implied swelling of the perylendiimide film during adsorption and may be explained by the capture of organic molecules. Fick’s law for early-time diffusion was used to characterize the swelling processes. Diffusion coefficients for swelling were proportional to the square root of time and were correlated with volatile organic compounds. Responses of N,N?-dicyclohexyl-3,4:9,10-perylene bis(dicarboximide) films to volatile organic compounds were characterized based on the physical properties of solvents. Films were more sensitive to chloroform compared to other volatile organic compounds. © 2016, Copyright © Taylor & Francis Group, LLC

Dye sensitized CO2 reduction over pure and platinized TiO2

TiO2 thin and thick films promoted with platinum and organic sensitizers including novel perylene diimide dyes (PDI) were prepared and tested for carbon dioxide reduction with water under visible light. TiO2 films were prepared by a dip coating sol-gel technique. Pt was incorporated on TiO2 surface by wet impregnation [Pt(on).TiO2], or in the TiO2 film [Pt(in).TiO2] by adding the precursor in the sol. When tris (2,2'-bipyridyl) ruthenium(II) chloride hexahydrate was used as sensitizer, in addition to visible light activity towards methane production, H-2 evolution was also observed. Perylene diimide derivatives used in this study have shown light harvesting capability similar to the tris (2,2'-bipyridyl) ruthenium(II) chloride hexahydrate

Characterization of 1,7-dibromo-N,N'-(bicyclohexyl)-3,4:9,10-perylendiimide Langmuir-Blodgett film for organic vapor sensing application

1,7-Dibromo-N,N'-(bicyclohexyl)-3,4:9,10-perylendiimide material (FY3) was used as a sensor element in this work. Different number of LB thin film layer was deposited onto a gold-coated glass substrate to produce a thin film sensor element. Fabrication processes were monitored by surface plasmon resonance (SPR) technique. The experimental SPR data were fitted using the Winspall software to evaluate the film thickness and refractive index of this material. Values of the thickness and refractive index of LB films were determined as 0.54 ± 0.01 nm for the thickness per monolayer, and 0.46 ± 0.08 for the refractive index. LB thin film sensor element was exposed to chloroform, benzene, toluene and ethyl alcohol vapors. In-situ SPR measurements showed that the response of the FY3 LB film for saturated chloroform vapor is much larger than the other vapors with 4 s recovery times and 5 s response time. The photodetector response change, ?I rf was monitored when FY3 LB film was exposed to these organic vapors and the response of the FY3 LB film to chloroform was also the largest among organic vapors with the ?I rf value of 0.11 au. It can be proposed that this sensing element deposited onto gold-coated glass substrates has a good sensitivity and selectivity for saturated chloroform vapor. © 2015 Elsevier B.V. All rights reserved

Fabrication of Langmuir-Blodgett thin film for organic vapor detection using a novel N,N?-dicyclohexyl-3,4:9,10-perylenebis (dicarboximide)

The Langmuir-Blodgett (LB) thin film fabrication and gas sensing properties of a novel N,N?-dicyclohexyl-3,4:9,10-perylenebis (dicarboximide) (FY2) is reported in this study. Surface pressure changes as a function of surface area of FY2 molecule at the water surface shows a well organized and stable monolayer with a 22.5 mN m-1 surface pressure value for LB film deposition. LB deposition processes is characterized by UV-vis spectroscopy and quartz crystal microbalance (QCM) measurement system. Transfer ratio values are found to be 0.93 for glass and 0.95 for quartz crystal substrate. Gas sensing properties of these LB films against volatile organic compounds (VOCs) such as chloroform, benzene, toluene and ethyl alcohol are studied using the QCM technique. The FY2 LB film sensor sensitivities are calculated for chloroform, benzene, toluene and ethyl alcohol, 5.32 × 10-4, 3.52 × 10-4, 1.32 × 10-4 and 1.16 × 10-4 Hz ppm-1, respectively. LB films are more sensitive to chloroform than other vapors and the response of the LB films to chloroform is fast, large and reversible. Associated limits of detection are found to be between 1.12 × 104 and 5.17 × 104 ppm for these organic vapors. The novel FY2 material is promising as a vapor sensing device at room temperature. © 2014 Elsevier B.V

Dye sensitized artificial photosynthesis in the gas phase over thin and thick TiO2 films under UV and visible light irradiation

Perylene diimide based organic sensitizers capable of electron generation under illumination were used to initiate gas phase photo reduction reactions on TiO2 thin and thick film surfaces. For comparison [Ru(Bpy)(3)](2+) dye sensitizers were also studied. The photo reduction Of CO2 was carried out under static conditions in the gas phase. TiO2 films were coated on hollow glass beads via a sol-gel procedure. Pt was incorporated on the films either by adding the precursor salt in the sol, Pt(in), or by wet impregnation of calcined film with an aqueous solution of the precursor salt, Pt(on). Organic sensitizers were incorporated on the films by wet impregnation of the film from an aqueous solution. Under UV illumination, the methane yields of platinized TiO2 thin films decreased in the following order: Pt(on).TiO2 > Pt(in).TiO2 > TiO2. The presence of organic sensitizers inhibited the catalytic activity of pure and platinized TiO2 thick films under UV illumination. The relative enhancement of the reaction yields in the presence of the organic sensitizer under visible light illumination depended on the presence of Pt as well as the incorporation method of Pt in the TiO2 structure. The reaction yields were better when Pt was impregnated on the TiO2 film than when Pt was incorporated in the Ti sol. On the other hand, pure or platinized TiO2 under visible light illumination was totally inactive indicating the role of the organic dye in generating catalytically active electrons under visible light

Water-soluble green perylenediimide (PDI) dyes as potential sensitizers for photodynamic therapy

A series of water-soluble green perylenediimide (PDI) dyes have been synthesized. On red light excitation, these dyes were shown to be efficient generators of singlet oxygen, and in cell culture media, they were shown to display significant light-induced cytotoxic effects on the human erythroleukemia cell line (K-562). It appears that highly versatile PDI dyes are likely to find new applications in photodynamic therapy