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This paper proposes molecular and supramolecular concepts for potential application in perovskite solar cells. New air-stable symmetrical imine, with thiadiazole moieties PPL2: (5E,6E)-N2,N5-bis(4-(diphenylamino)benzylidene)-1,3,4-thiadiazole-2,5-diamine), as a hole-transporting material was synthesised in a single-step reaction, starting with commercially available and relatively inexpensive reagents, resulting in a reduction in the cost of the final product compared to Spiro-OMeTAD. Moreover, camphorsulfonic acid (CSA) in both enantiomeric forms was used to change the HOMO-LUMO levels and electric properties of the investigated imine-forming complexes. Electric, optical, thermal, and structural studies of the imine and its complexes with CSA were carried out to characterise the new material. Imine and imine/CSA complexes were also characterised in depth by the proton Nuclear Magnetic Resonance 1H NMR method. The position of nitrogen in the thidiazole ring influences the basicity of donor centres, which results in protonation in the imine bond. Simple devices of ITO/imine (with or without CSA(−) or CSA(+))/Ag/ITO architecture were constructed, and a thermographic camera was used to find the defects in the created devices. Electric behaviour was also studied to demonstrate conductivity properties under the forward current. Finally, the electrical properties of imine and its protonated form with CSA were compared with Spiro-OMeTAD. In general, the analysis of thermal images showed a very similar response of the samples to the applied potential in terms of the homogeneity of the formed organic layer. The TGA analysis showed that the investigated imine exhibits good thermal stability in air and argon atmospheres. [ABSTRACT FROM AUTHOR]

Three (4,4′-((1E,1′E)-(2,5-bis(octyloxy)-1,4-phenylene)bis(ethene-2,1-diyl))bis-(E)-N-(2,5-bis(octyloxy)benzylidene)) imine derivatives were synthesized via a condensation reaction with p-toluenesulfonic acid as a catalyst. The effects of the end groups and vinylene (–HC=CH–) moieties on the structural, thermal, optical, electrochemical and photovoltaic properties of imines were investigated to check the influence of TiO2 on the imine properties. The thermal behavior of imines and their complexes with TiO2 was widely investigated using FT-IR, XRD, DSC and POM methods in order to determine the order type in the imine structure. All imines present the highest occupied molecular orbital (HOMO) levels of about −5.39 eV (SAI1 and SAI2) and −5.27 eV (SAI3) and the lowest unoccupied molecular orbital (LUMO) levels at about −3.17 eV. The difference of the end groups in the imines in each case did not affect redox properties. Generally, both oxidation and reduction are easier after TiO2 addition and it also changes the HOMO–LUMO levels of imines. Moreover, changes in the characteristic bands for imines in the region 1500–1700 cm−1 observed as a drastic decrease of intensity or even disappearance of bands in the imine : TiO2 mixture suggest the formation of a complex (C=N)–TiO2. Organic devices with the configuration of ITO/TiO2/SAIx (or SAIx : TiO2)/Au were fabricated and investigated in the presence and absence of visible light irradiation with an intensity of 93 mW cm−2. In all imines and complexes with TiO2, the generation of the photocurrent indicates their use as photodiodes and the best result was observed for SAI3 : TiO2 complexes. [ABSTRACT FROM AUTHOR]

Two bent-shaped imines (9E)-N-(3-((E)-(4-hexadecylphenylimino)methyl)benzylidene)-4-hexadecylbenzenamine (SL1) and (10E)-N-(3-((E)-(4-(perfluorooctyl)phenylimino)methyl)benzylidene)-4-(perfluorooctyl)benzenamine (SL2) were prepared by condensation reaction in N,N-dimethylacetamide to study their thermal, structural and electrochemical properties, as well as their mixtures with titanium dioxide. Chemical structure, temperature and TiO2 influences on the phase transition temperatures, enthalpy, texture and molecular dynamics of both imines were investigated by differential scanning calorimetry, polarising optical microscopy and Fourier transform middle-infrared absorption spectroscopy during heating and cooling. Changes in the surface morphology of the imines and their mixtures with TiO2 were registered by atomic force microscopy. X-ray study showed the tendency to form lamellas in the case of SL2 as an effect of the presence of two terminal perfluorinated alkyl chains connected to a polar mobile aromatic core, which resulted in microsegregation. Additionally, TiO2 influences the energy gap and HOMO-LUMO levels of imines as was detected by cyclic voltammetry. Finally, devices with two types of architectures, such as ITO/TiO2/SL1(or P3HT)/Au and ITO/TiO2/SL1:P3HT/Au were constructed and investigated under irradiation intensity of 97.7 mW/cm2. [ABSTRACT FROM AUTHOR]

A new piperazine imine, (7E)-N-((4-((E)-(4-hexadecylphenylimino)methyl) piperazin-1-yl)methylene)-4-dodecylbenzenamine, has been synthesized by the condensation of 1,4-piperazinedicarboxaldehyde with 4- hexadecylaniline. The imine was characterized by cyclic voltammetry, Fourier transform middle-infrared absorption spectroscopy and X-ray diffraction. Thermal properties of imine was analyzed by differential scanning calorimetry method during first and second heating scan at 10 and 20 °C/min. Texture of imine was investigated by polarized optical microscopy and atomic force microscopy. Furthermore, imine was blended with titanium dioxide in anatase form and fully characterized by the same methods. Piperazine imine and its mixture with titanium dioxide exhibited only a transition from crystal to isotropic state. Imine exhibits two-step reduction wave attributed to one-electron transfer in each step as was found by cyclic voltammetry. Both titanium dioxide and poly(3-hexylthiophene) change the electrochemical properties of piperazine imine, however, in different ways. Studied imine blended with titanium dioxide exhibited higher value of energy band gap than pure piperazine imine and lower Eg than pure poly(3-hexylthiophene). [ABSTRACT FROM AUTHOR]

We report on the application of l,d-poly(lactic acid) (l,d-PLA) with dispersed Single-Walled Carbon Nanotubes (SWCN) as a flexible translucent electrode for organic devices. We used commercially available nanotubes in various weight ratios from 0 to 8% dispersed in chloroform polymeric solution by ultrasonication and were drop cast. The created hybrid materials were investigated by differential scanning calorimetry to determine the influence of SWCN content on the thermal behavior, while polarizing optical microscope was used to find the effect of mechanical deformations on the textures. Drop-cast films were studied by optical transmittance, conductivity, dielectric properties and by thermal imaging under applied potential. Thermal imaging provided evidence of visible voltage-activated conduction. Simple mechanical deformation such as bending with stretching at edge to ca. 90 and elongation test were performed. Moreover, interactions between l,d-poly(lactic acid) and SWCN were investigated by FT-IR and NMR spectroscopy. Finally, we can conclude that the thermographic examination of created films permits fast, simple and inexpensive localization of defects on the surface of l,d-PLA:SWCN film, together with the electrical properties of the films. [ABSTRACT FROM AUTHOR]

Low-modified liquid-crystalline polyether (CP36), as a model compound, was synthesised with the purpose of preparing a membrane with columnar ionic channels. A free-standing cation permselective biomimetic membrane was successfully prepared and found to have channels made of polymeric columns homeotropically oriented, which was confirmed in X-ray diffraction (XRD) analysis. A first insight into a real-time interaction between two selected cations: H+ and Na+, and polyether during transport through the polymeric membrane was demonstrated using joined chronoamperometry and Raman spectroscopy techniques. Raman studies unveiled the possibility for smaller protons to bypass the usual ionic pathway via polyetheric chain and use outer part of ionic channel for conduction thanks to ester bonds. [ABSTRACT FROM AUTHOR]

A new unsymmetrical imine with four thiophene rings was synthesized in a one-step reaction, starting from the commercially available and relatively inexpensive reagents. The obtained imine in the form of thin films exhibited photoluminescence properties in the 1.8-2.4 eV energy range and a photoluminescence lifetime of about 0.3 ns. The HOMO and LUMO levels of the imine determined by cyclic voltammetry were at about -5.19 eV and -3.05 eV, respectively. The density functional theory was applied to calculate the geometric and electronic structure of the imine. The UV-Vis spectra showed that the absorption range of the imine overlaps with that of PC 70 BM, and the absorption peak at the maximum of the imine at 424 nm is located between the two maxima at 404 nm and 461 nm of the fullerene derivative. The electron acceptor and donor activity of the imine was tested in the solar cell architecture: glass/ITO/PEDOT:PSS/active layer/In/Al. The best photovoltaic parameters, with very good reproducibility for each 8 pixels in the cell, were found for the active layer based on ternary mixture PTB7:PC 70 BM:imine at a weight ratio 8 : 13 : 1, with the power conversion efficiency of about 4%. The external quantum efficiency of devices with the imine was found to be about 40% at 3.3 eV. The thermal imaging together with the recorded current response at increasing potential showed that the presence of imine in the composition has a beneficial impact in terms of current flow stability at temperatures above 200 °C, compared to two component layers with the same imine as an additive., Competing Interests: All authors have read and agreed to the published version of the manuscript., (This journal is © The Royal Society of Chemistry.)

Planar perovskite solar cells were fabricated on F-doped SnO 2 (FTO) coated glass substrates, with 4,4'-((1E,1'E)-((1,2,4-thiadiazole-3,5-diyl)bis(azaneylylidene))bis(methaneylylidene))bis( N , N -di-p-tolylaniline) (bTAThDaz) as hole transport material. This imine was synthesized in one step reaction, starting from commercially available and relatively inexpensive reagents. Electrochemical, optical, electrical, thermal and structural studies including thermal images and current-voltage measurements of the full solar cell devices characterize the imine in details. HOMO-LUMO of bTAThDaz were investigated by cyclic voltammetry (CV) and energy-resolved electrochemical impedance spectroscopy (ER-EIS) and were found at -5.19 eV and -2.52 eV (CV) and at -5.5 eV and -2.3 eV (ER-EIS). The imine exhibited 5% weight loss at 156 °C. The electrical behavior and photovoltaic performance of the perovskite solar cell was examined for FTO/TiO 2 /perovskite/bTAThDaz/Ag device architecture. Constructed devices exhibited good time and air stability together with quite small effect of hysteresis. The observed solar conversion efficiency was 14.4%.

We report here the preparation and thermal, electrical and mechanical characterization of binary and ternary films based on l,d-poly(lactic acid) (l,d-PLA) and 4'-pentyl-4-biphenylcarbonitrile (5CB) and Single Walled Carbon Nanotubes (SWCN) with various weight ratio. The transitions for all investigated hybrid compositions detected by differential scanning calorimetry method were shifted to lower temperatures with increasing the concentration of 5CB in the mixture with polymer. Frequency domain dielectric spectroscopy method and thermal imaging together with polarized optical microscope were used to study electric and structural properties of created hybrid compositions. The best electrical conductivity was observed for hybrid composite l,d-PLA:5CB:SWCN with ratio 10:1:0.5 w / w / w - resistance of 41.0 Ω and thermal response up to 160 °C without causing any damages. Films in crystal form are much more inflexible than in amorphous and can be explain by the cold crystallization occurs at heating while the materials changed their physical state. The value of ε' increases with increasing the 5CB admixture. Moreover, the addition of 5CB to l,d-PLA resulted in increased flexibility of polymeric base films. The best material flexibility and short-term strength were obtained for l,d-PLA sample with 9% 5CB content., Competing Interests: The authors declare no conflict of interest.

Three (4,4'-((1E,1'E)-(2,5-bis(octyloxy)-1,4-phenylene)bis(ethene-2,1-diyl))bis-(E)-N-(2,5-bis(octyloxy)benzylidene)) imine derivatives were synthesized via a condensation reaction with p-toluenesulfonic acid as a catalyst. The effects of the end groups and vinylene (-HC[double bond, length as m-dash]CH-) moieties on the structural, thermal, optical, electrochemical and photovoltaic properties of imines were investigated to check the influence of TiO2 on the imine properties. The thermal behavior of imines and their complexes with TiO2 was widely investigated using FT-IR, XRD, DSC and POM methods in order to determine the order type in the imine structure. All imines present the highest occupied molecular orbital (HOMO) levels of about -5.39 eV (SAI1 and SAI2) and -5.27 eV (SAI3) and the lowest unoccupied molecular orbital (LUMO) levels at about -3.17 eV. The difference of the end groups in the imines in each case did not affect redox properties. Generally, both oxidation and reduction are easier after TiO2 addition and it also changes the HOMO-LUMO levels of imines. Moreover, changes in the characteristic bands for imines in the region 1500-1700 cm-1 observed as a drastic decrease of intensity or even disappearance of bands in the imine : TiO2 mixture suggest the formation of a complex (C[double bond, length as m-dash]N)-TiO2. Organic devices with the configuration of ITO/TiO2/SAIx (or SAIx : TiO2)/Au were fabricated and investigated in the presence and absence of visible light irradiation with an intensity of 93 mW cm-2. In all imines and complexes with TiO2, the generation of the photocurrent indicates their use as photodiodes and the best result was observed for SAI3 : TiO2 complexes.

The effect of the presence of titanium dioxide in two new imines, ( E , E )-(butane-1,4-diyl)bis(oxybutane-4,1-diyl) bis(4-{[(benzo[ d ][1,3]thiazol-2-yl)methylidene]amino}benzoate) (SP1) and ( E )- N -[(benzo[ d ][1,3]thiazol-2-yl)methylidene]-4-dodecylaniline (SP2), on the properties and stability of imine:TiO 2 composites for organic device applications were examined. The investigated titanium dioxide (in anatase form, obtained via the sol-gel method) exhibited a surface area of 59.5 m 2 /g according to Brunauer-Emmett-Teller theory, and its structure is a combination of both meso- and microporous. The average pore diameter calculated by the Barrett-Joyner-Halenda method was 6.2 nm and the cumulative volume of pores was 0.117 m 3 /g. The imine SP1 exhibited columnar organization (Col), while SP2 revealed a hexagonal columnar crystalline phase (Col hk ). The imine:TiO 2 mixtures in various weight ratio (3:0, 3:1, 3:2, 3:3) showed a lower energy gap and HOMO-LUMO energy levels compared to pure TiO 2 . This implies that TiO 2 provides not only a larger surface area for sensitizer adsorption and good electron collection, but also causes a shift of the imine energy levels resulting from intermolecular interaction. Also the temperature of the phase transition was slightly affected with the increase of TiO 2 concentration in imine-based composites. The changes observed in the Fourier transform middle-infrared absorption (FT-MIR) spectra confirmed the significant influence of TiO 2 on structural properties of both investigated imines. Similar interactions of oxygen vacancies existing on the TiO 2 surface with SP1 and SP2 were observed. The imine:TiO 2 mixtures showed good air stability and reusability, which demonstrates its potential for organic device applications.