Impact of the molecular structure of an indandione fragment containing azobenzene derivatives on the morphology and electrical properties of thin films
Abstract The solution casting method is low-cost processing method. Moreover, it is possible to prepare amorphous thin films by using this method, and thus, both optical quality and electrical properties could be improved in compare to polycrystalline films made by thermal evaporation in vacuum. Therefore, low-molecular-weight compounds that form amorphous structure from solution could be promising in organic electronics. In this work film morphology, molecule energy levels, and charge carrier mobility in thin films of indandione fragment containing azobenzene derivatives were studied. Deep charge carrier trapping states that drastically influenced charge carrier mobility were observed for …
Photoelectrical Properties and Energetical Structure of Thin Films of Indandione Derivatives
A sandwich type structure of two dimetilaminobenziliden-1,3-indandione (DMABI) derivatives placed between metal electrodes was made to investigate the photoelectrical properties of these derivatives. DMABI is an organic isolator with a wide energy gap and high quantum efficiency of the photogeneration, DMABI derivatives have received also considerable attention because of its large dipole moment and optical nonlinearities. Besides, since it is a photosensitive material, its use in solar systems is very promising. The energy gap of each material and combined system was observed from the spectral dependence of the quantum efficiency of the photoconductivity and results are compared with resul…
Photovoltaic effect in bulk heterojunction system with glass forming indandione derivative DMABI-6Ph
The aim of the work is to evaluate possible use of 2-[[4-(bis(2-trityloxyethyl)amino)phenyl]methylene]indane-1,3-dione (DMABI-6Ph) as light absorbing material for solar cells. DMABI-6Ph is a perspective material due to its good photoelectrical, thermal and chemical properties. The main advantage of DMABI-6Ph is its ability to form amorphous films by wet-casting methods thus allowing using the compound in organic solar cells made from solution. For now most popular materials for solution processable solar cells are polymer P3HT and fullerene derivative PCBM, but lot of investigations are in the field of new low molecular weight materials to replace the polymer. Photoelectrical measurements w…
Light emitting and electrical properties of pure amorphous thin films of organic compounds containing 2-tert-butyl-6-methyl-4H-pyran-4-ylidene
Abstract Low molecular weight organic compounds which make thin films from organic solutions would be a great benefit in future organic light emitting systems. Two most important advantages should be mentioned. First – repeatability of synthesis of small molecules is better than of polymers. Second – wet casting methods can be applied. In this paper we present optical and opto-electrical properties of three glassy forming compounds containing 2-tert-butyl-6-methyl-4H-pyran-4-ylidene fragment as a backbone. They have the same N,N-dialkylamino electron donating group with attached bulky trityloxyethyl groups. The difference between these compounds is in an electron acceptor group. One has ind…
Photoelectrical properties of indandione fragment containing azobenzene compounds
Organic materials are becoming more popular due to their potential application in electronics. Low molecular weight materials possible produce from solution are in special consideration. It gives the possibility to avoid both thermal evaporation in vacuum, and use of polymers in thin film preparation process. Indandione fragment containing azobenzene compounds are one of such materials. These compounds are good candidates for use in design of novel molecular electronic devices due to their possibility to form amorphous structure from solution thus allowing developing flexible, small size systems with low production costs. In this work three indandione fragment containing azobenzene compound…
A Novel Gas Sensor Transducer Based on Phthalocyanine Heterojunction Devices
Abstract: Experimental data concerning the changes in the current-voltage (I-V) perfor-mances of a molecular material-based heterojunction consisting of hexadecafluorinated nickel phthalocyanine (Ni(F 16 Pc)) and nickel phthalocyanine (NiPc), (Au|Ni(F 16 Pc)|NiPc|Al) are introduced as an unprecedented principle of transduction for gas sensing performances. The respective n - and p -type doped-insulator behaviors of the respective materials are supported, owing to the observed changes in surface potential (using the Kelvin probe method) after submission to electron donor (ammonia) and electron acceptor gases (ozone). On the other hand, the bilayer device exhibits strong variations in the bui…
Photoelectrical properties of thin films of DMABI derivatives
Organic thin films with semiconducting properties have been intensively studied in nowadays due to very promising applications in organic electronics, for example, organic photovoltaic. Among organic semiconductors, group of indandiones with their photoelectrical properties, thermal and chemical stability are good candidates for use in design of novel molecular electronic devices. We have investigated photoconductivity quantum efficiency and its spectral dependence of two dimetilaminobenzylidene-1,3-indandione derivatives. Values of the photoconductivity threshold energy and optical energy gap are obtained. These results are compared with calculated transfer energy gap estimated according t…
Towards direct measurements of remitted photon path lengths in skin: kinetic studies in the range 520-800 nm
Skin-remitted picosecond laser pulses have been detected at variable input-output fiber distances (8 … 20 mm) in the spectral range 520-800 nm, with subsequent analysis of the pulse shape changes. Transfer functions representing the temporal responses of remitted photons to infinitely narrow δ-pulse excitation have been calculated. Parameters related to the photon path length in skin – input-output pulse peak delays, pulse FWHM, travel times of the “initial” photons and distributions of the remitted photon path lengths – are presented and analyzed. The measurement results are in general agreement with the photon propagation model expectations