A new look at imines and their mixture with PC71BM for organic, flexible photovoltaics (original) (raw)
Related papers
Materials
In this paper, four new aromatic imines containing at least one thiazole-based heterocycle were analyzed in detail by UV–Vis spectroscopy, taking into consideration their chemical structures and interactions with PTB7, a known polymeric electron donor widely used in bulk heterojunction organic solar cells. It is demonstrated that the absorption spectra of the investigated active compositions can be modified not only by changing the chemical structure of imine, but also via formulations with PTB7. For all investigated imines and PTB7:imine compositions, calibration curves were obtained in order to find the optimum concentration in the composition with PTB7 for expansion and optimization of absorption spectra. All imines and PTB7:imine compositions were investigated in 1,2-dichlorobenzene by UV–Vis spectroscopy in various concentrations, monitoring the changes in the π–π* and n–π* transitions. With increasing imine concentrations, we did not observe changes in absorption maxima, while...
Improvement of Solar PV Efficiency. Potential Materials for Organic Photovoltaic Cells
Organic photovoltaic (OPV) cells are considered as a viable alternative to those energy sources currently in use. In this work three derivatives of original N,N'- dimetilaminobenziliden-1,3-indandione (DMABI) material are presented as potential materials for OPV. The photoconductivity threshold energy was evaluated from the perspective of spectral dependence of photoconductivity quantum efficiency, and the optical energy gap was defined to determine the optical absorption spectra. The absorption spectra of derivatives are blue shifted compared to original DMABI. Use of these derivatives in multilayer solar cells with original DMABI makes it possible to broaden the spectral response range of OPV.
NEW ORGANIC SEMICONDUCTOR MATERIALS APPLIED IN ORGANIC PHOTOVOLTAIC AND OPTICAL DEVICES
The development of flexible organic photovoltaic solar cells, using an optically transparent substrate material and organic semiconductor materials, has been widely utilized by the electronic industry when producing new technological products. The flexible organic photovoltaic solar cells are the base Poly (3,4ethylenedioxythiophene), PEDOT, Poly(3-hexyl thiophene, P3HT, Phenyl-C61-butyric acid methyl ester, PCBM and Polyaniline, PANI, were deposited in Indium Tin Oxide, ITO, and characterized by Electrical Measurements and Scanning Electron Microscopy (SEM).
Concept of Organic Photovoltaics: Operational Principles and Materials
Acta Electrotechnica et Informatica, 2013
Organic molecules possessing a π-conjugated (hetero)aromatic backbone are capable of transporting charge and interact efficiently with light. Therefore, these systems can act as semiconductors in opto-electronic devices similar to inorganic materials. However, organic chemistry offers tools for tailoring materials' functional properties via modifications of the molecular units, opening new possibilities for inexpensive device manufacturing. In this presentation, we discuss exploitation of such organic molecular systems in photovoltaics; the operation, advantages, and limitations of molecular donor-acceptor heterojunction structures.
Multilayered Thin Films for Organic Photovoltaics
2010
This work investigates the photoinduced interactions between different organic chromophores, thus identifying possible materials for organic photovoltaic applications. The intermolecular electron transfer (ET) in layered structures centered on a covalently bridged porphyrin-fullerene dyad (P-F) was studied by means of electrical and spectroscopic methods. When excited, the dyad initiates the vectorial ET in the films, and secondary processes take place after the charge separation between the porphyrin and fullerene moieties of P-F. This study showed that violanthrone-79 (V-79) and two different perylene derivatives (PDI and PTCDI) were capable to accept electrons from the photoinduced fullerene anion of P-F. Longer-lived electrical and spectroscopic signals were achieved when the film structures were expanded to multilayered configurations containing an electrondonor, the P-F dyad, and an electron-acceptor. The electron-donor material used was poly(3-hexylthiophene) (PHT).
Characterisation of materials for organic photovoltaics
2008
Organic solar cells offer the possibility for lightweight, flexible, and inexpensive photovoltaic devices. This thesis studies the physics of a wide range of materials designed for use in organic solar cells. The materials investigated include conjugated polymers, conjugated dendrimers, and inorganic nanocrystals. The materials studied in this thesis fall into five categories: conjugated polymers blended with a buckminsterfullerene derivative PCBM, nanocrystals synthesised in a conjugated polymer matrix, conjugated polymers designed for intramolecular charge separation, conjugated dendrimers blended with PCBM, and nanocrystals synthesised in a matrix of conjugated small molecules or dendrimers. Conjugated polymers blended with PCBM have been extensively studied for photovoltaic applications, and hence form an ideal test bed for new experiments. In this thesis this blend was used to achieve the first pulsed electrically detected magnetic resonance experiments on organic solar cells. Nanocrystals are attractive for photovoltaics because it is possible to tune their band gap across the solar spectrum. In this thesis a one-pot synthesis is used to grow PbS and CdS nanocrystals in conjugated polymers, soluble small molecules, and dendrimers, and characterisation is performed on these composites. Previous work on dendrimer: nanocrystal composites has been limited to non-conjugated molecules, and the synthesis developed in this thesis extends this work to a conjugated oligomer and a conjugated dendrimer. This synthesis can potentially be extended to a variety of conjugated soluble small molecule: nanocrystal and dendrimer: nanocrystal systems. i ii Conjugated dendrimers have been successfully employed in organic light emitting diodes, and in this thesis they are applied to organic solar cells. Materials based on fluorene and cyanine dye cores show excellent absorption tunablility across the solar spectrum. A set of electronically assymetric polymers designed for intramolecular charge separation were investigated. Quenching of the luminescence was observed, and light induced electron paramagnetic resonance measurements revealed that photoexcitation led to approximately equal numbers of positive polarons and nitro centred radical anions. This indicates that charge separation is occurring in these molecules. Declaration I, Elizabeth Alice Thomsen, hereby certify that this thesis, which is approximately 45,000 words in length, has been written by me, that is the record of work carried out by me, and that it has not been submitted in any previous application for a higher degree. Elizabeth A. Thomsen Date I was admitted as a research student in September 2004 and as a candidate for the degree of Ph.D. in September 2005; the higher study for which this is a record was carried out in the University of St. Andrews between 2004 and 2007. Elizabeth A. Thomsen Date I hereby certify that the candidate has fulfilled the conditions of the Resolution and Regulations appropriate for the degree of Ph.D. in the University of St. Andrews and that the candidate is qualified to submit this thesis in application for that degree.
New Organic Materials for Photovoltaics
2011
This report presents the results of investigations carried out for polymer-and low-weight molecular materials prepared in the form of thin films by various methods, namely the thermal vacuum evaporation and chemical vapour deposition. The influence of the technological conditions on the structure, surface morphology, and electronic properties of selected organic thin films, including polyazomethines, phthalocyanines, and perylene derivatives as well as their blends, is discussed from the point of view of the potential applications for photovoltaic organic devices.