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 were made to determine molecule ionization and electron affinity levels of DMABI-6Ph. Difference of 2.06 eV between DMABI-6Ph ionization level and PCBM affinity level was obtained. Accordingly open circuit voltage of system DMABI-6Ph:PCBM was measured up to 0.78 V. The best power conversation efficiency was 0.11 % for the DMABI-6Ph:PCBM mass fraction 2:1. Limiting factor for high efficiency could be low charge carrier mobility which can be increase by additional DMABI-6Ph modification.European Social Fund Project No. 2013/0045/1DP/1.1.1.2.0/13/APIA/VIAA/018; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

A Novel Gas Sensor Transducer Based on Phthalocyanine Heterojunction Devices

Experimental data concerning the changes in the current-voltage (I-V) perfor-mances of a molecular material-based heterojunction consisting of hexadecafluorinatednickel phthalocyanine (Ni(F16Pc)) and nickel phthalocyanine (NiPc),(Au|Ni(F16Pc)|NiPc|Al) are introduced as an unprecedented principle of transduction for gassensing performances. The respective n- and p-type doped-insulator behaviors of therespective materials are supported, owing to the observed changes in surface potential(using the Kelvin probe method) after submission to electron donor (ammonia) and electronacceptor gases (ozone). On the other hand, the bilayer device exhibits strong variations inthe built-in potential of the junction and in its rectification ratio. Moreover, large increasesoccur in forward and reverse currents in presence of ammonia vapors. These make possiblea multimodal principle of detection controlled by a combined effect between theheterojunction and the NiPc|Al contact. Indeed, this metal/organic junction plays a criticalrole regarding the steady asymmetry of the I-V profiles during the device’s doping evenusing high ammonia concentrations. This approach offers a more sophisticated alternative tothe classically studied, but at times rather operation-limited, resistive gas sensors

Impact of the Molecular Structure of an Indandione Fragment Containing Azobenzene Derivatives on the Morphology and Electrical Properties of Thin Films

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 polycrystalline films with the model compound 2-(4-((4-(dimethylamino)phenyl)diazenyl)benzylidene)-1H-indene-1,3(2H)- dione. This issue was overcome by attaching bulky groups to the model compound. An amorphous thin film without deep trapping states was obtained. Electron and hole mobilities of these materials at electric field 160 to 600 kV/cm were between 10-5 and 10-6 cm2V-1s-1 and between 10-6 to 10-7 cm2V-1s-1, respectively. Charge carrier mobility, molecular ionization energy, and electron affinity energy were influenced by bulky groups

A novel gas sensor transducer based on phthalocyanine heterojunction devices

Abstract: Experimental data concerning the changes in the current-voltage (I-V) performances of a molecular material-based heterojunction consisting of hexadecafluorinated nickel phthalocyanine (Ni(F16Pc)) and nickel phthalocyanine (NiPc), (Au|Ni(F16Pc)|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 built-in potential of the junction and in its rectification ratio. Moreover, large increases occur in forward and reverse currents in presence of ammonia vapors. These make possible a multimodal principle of detection controlled by a combined effect between the heterojunction and the NiPc|Al contact. Indeed, this metal/organic junction plays a critical role regarding the steady asymmetry of the I-V profiles during the device’s doping even using high ammonia concentrations. This approach offers a more sophisticated alternative to the classically studied, but at times rather operation-limited, resistive gas sensors