ИСТИНА

Recent progress in organic field-effect transistors (OFET) based on 2D (mono- of a few layer) single crystals stimulates the interest to 2D organic light-emitting transistors (OLETs), which can be used in lightweight, flexible and transparent screens. The latter needs materials combining bright luminescence with charge transport [1], and thiophene-phenylene co-oligomers are among the most promising materials for light-emitting transistors [2]. In this work, we synthesize two thiophene-phenylene co-oligomers with PTTP and PTPTP (P stands for phenylene, and T stands for thiophene) conjugated cores and decyl terminal substituents, DD-PTTP and DD-PTPTP. 2D films were grown from ortho-dichlorobenzene solution spin-cast at concentrations of 0.2-0.5 g/l on Si substrates with thermally-grown SiO2. For both oligomers, 2D films with lateral dimensions in the range of 300–600 μm were grown. OLETs were fabricated on SiO2/Si substrates with bottom gold electrodes (Figure 1d). 2D OLETs demonstrated hole transport and electroluminescence (Figure 1c). Using DD-PTTP and DD-PTPTP as active layers, we fabricated polycrystalline (PC) OLETs samples with low and high-work function electrodes to study light emission in devices. Optical image of an operating OLETs are shown in Figure 1 (a,b). OLETs demonstrated bright electroluminescent (for both oligomers EQE is about 0,1) in the visible range of light (Figure 1e). Our study shows that OLETs based on DD-PTTP and DD-PTPTP oligomers demonstrated good electroluminescent properties and could be practical application in the fabrication of optoelectronic devices. Figure 1. Images of OLETs based on PC films (a,b) and 2D crystals (c-f) of DD-PTTP (a), DD-PTPTP (b,c,d). Panels a-c present operating mode of OLETs. Electroluminescence spectrum for both oligomers (е). This work was supported by RSF (project № 22-79-10122) 1. Fedorenko R., et al., Adv. Electron. Mater., 8, 2022, 2101281. 2. Hotta S., et al., J. Mater. Chem. C, 2014, 2, 965-980.