Spectroscopic and Physicochemical Investigations of Azomethines with Triphenylamine Core towards Optoelectronics

Three new azomethines based on triphenylamine with two or three substituents were obtained. Chemical structure and purity were confirmed by ¹H NMR, FTIR elemental analysis and mass spectroscopy. The investigations were focused on the relationship between chemical structure and properties important for optoelectronic materials. Thus, the studies of thermal, optical and electrochemical properties were carried out based on differential scanning calorimetry, thermogravimetric analysis, electronic absorption, photoluminescence and cyclic voltammetry measurements. The ongoing consideration of experimental results was complemented by theoretical calculations using the density functional theory method. The donor activity of obtained compounds was tested in bulk-heterojuntion photovoltaic cells with structure ITO/PEDOT:PSS/imine:PCBM/Al and ITO/PEDOT:PSS/imine:P3HT:PCBM/Al). The effect of the presence of the amino-thiophene-3,4-dicarboxylic acid diethyl ester groups and various number of hexyloxyphenyl units on imines properties was demonstrated.

Efficiency enhancement of perovskite solar cells via incorporation of phenylethenyl side arms into indolocarbazole-based hole transporting materials

Small-molecule hole transporting materials based on an indolocarbazole core were synthesized and incorporated into perovskite solar cells, which displayed a power conversion efficiency up to 15.24%. The investigated hole transporting materials were synthesized in three steps from commercially available and relatively inexpensive starting materials without using expensive catalysts. Various electro-optical measurements (UV-vis, CV, hole mobility, DSC, TGA, ionization potential) have been carried out to characterize the new hole transporting materials.

Bifunctional star-burst amorphous molecular materials for OLEDs: achieving highly efficient solid-state luminescence and carrier transport induced by spontaneous molecular orientation

Bifunctional star-burst amorphous molecular materials displaying both efficient solid-state luminescence and high hole-transport properties are developed in this study. A high external electroluminescence quantum efficiency up to 5.9% is attained in OLEDs employing the developed amorphous materials. It is revealed that the spontaneous horizontal orientation of these light-emitting molecules in their molecular-condensed states leads to a remarkable enhancement of the electroluminescence efficiencies and carrier-transport properties.