Novel host materials containing dibenzofuran and dibenzothiophene, (5-(8-(9H-carbazole-9-yl)dibenzo[b,d] furan-2-yl)thiophene-2-yl)diphenylphosphine oxide (3, CFTPO) and (5-(8-(9H-carbazol-9-yl)dibenzo[b,d]thiophen-2-yl)thiophen-2-yl)diphenylphosphine oxide (4, CTTPO) were synthesized and employed as yellow host materials. The CFTPO host material had bipolar characteristics because it contained carbazole, dibenzofuran, and diphenylphosphine oxide charge transport units with triplet energy (2.56 eV), high external quantum efficiency (24.4%), and power efficiency (63.4 lm/W) in a yellow phosphorescent device. The CTTPO host material also had bipolar characteristics because it contained carbazole, dibenzothiophene, and diphenylphosphine oxide charge transport units with triplet energy (2.52 eV), high quantum efficiency (25.4%), and power efficiency (65.7 lm/W) in a yellow phosphorescent device.

Two new benzo[b]thieno[2,3-d]thiophene (BTT) derivatives, 2-(benzo[b]thiophen-5-yl)benzo[b]thieno[2,3-d]thiophene (compound 2), and 2-(benzo[b]thieno[2,3-d]thiophene-2yl)dibenzo[b,d]thiophene (compound 3) have been synthesized and utilized as solution-processable small molecular organic semiconductors for organic field-effect transistors (OFETs). The physicochemical characteristics of the recently created substances were analyzed using thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), and UV-vis spectroscopy. Subsequently, the above-mentioned substances were employed as semiconductor layers in bottom-gate/top-contact OFETs through solution shearing methods for device fabrication, and their electrical performances were meticulously evaluated. The outcoming OFET device displayed p-channel behavior, demonstrating hole mobility of up to 0.005cm2/Vs and a current on/off ratio higher than 106.

Solution-processable [1]benzothieno[3,2-b]benzothiophene (BTBT) derivatives with various end-capping groups, 2-(phenylethynyl)benzo[b]benzo[4,5]thieno[2,3-d]thiophene (Compound 1), 2-octyl-7-(5-(phenylethynyl)thiophen-2-yl)benzo[b]benzo[4,5]thieno[2,3-d]thiophene (Compound 2), and triisopropyl((5-(7-octylbenzo[b]benzo[4,5]thieno[2,3-d]thiophen-2-yl)thiophen-2-yl)ethynyl)silane (Compound 3), have been synthesized and characterized as active layers for organic field-effect transistors (OFETs). Thermal, optical, and electrochemical properties of the newly synthesized compounds were characterized using thermogravimetric analysis (TGA), a differential scanning calorimeter (DSC), UV–vis spectroscopy, and cyclic voltammetry (CV). Thin films of each compound were formed using the solution-shearing method and the thin film surface morphology and texture of the corresponding films were characterized using atomic force microscopy (AFM) and θ–2θ X-ray diffraction (XRD). All semiconductors exhibited p-channel characteristics in ambient and Compound 1 showed the highest electrical performance with a carrier mobility of ~0.03 cm2/Vs and current on/off ratio of ~106.

Newly synthesized benzo[b]thieno[2,3-d]thiophene derivatives were employed as active layers of organic field effect transistors, and these transistors showed decent electrical performance.

In this paper, four organic materials based on dithieno[3,2-b : 2',3'-d]thiophene (DTT) core structure with end-capping groups (phenyl and thienyl) and linker (acetylenic and olefinic) between DTT-core and end-capping groups were synthesized and characterized as solution-processable organic semiconductors (OSCs) for organic field-effect transistors (OFETs). Thermal, optical, and electrochemical properties of the corresponding materials were determined. Next, all DTT-derivatives were coated by solution-shearing method, and the thin-film microstructures and morphologies were investigated. To investigate the electrical performance of four newly synthesized DTT-derivatives, bottom-gate/top-contact OFETs were fabricated and characterized in ambient condition. It was found that substitution of acetylenic for olefinic linkers between DTT-cores and end-capping groups enhanced device performance. Especially, the resulting OFETs based on the compound containing phenylacetylene exhibited the highest hole mobility of 0.15 cm2 /Vs and current on/off ratio of ∼106 , consistent with film morphology and texture showing long range interconnected crystalline grains and strong diffraction peaks.

In this study, novel benzo[b]thieno[2,3-d]thiophene (BTT) derivatives, 2-(thiophene-2-yl)benzo[b]thieno[2,3-d] thiophene (compound 1), 2-(5-(2-ethylhexyl)thiophene-2-yl)benzo[b]thieno[2,3-d]thiohpene (compound 2), and 2-(5-octylthiophene-2-yl)benzo[b]theino[2,3-d]thiohpene (compound 3), were synthesized and characterized as solution-processable organic semiconductors (OSCs) for organic field-effect transistors (OFETs). Developed organic compounds were analyzed by thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), UV-vis spectroscopy, and cyclic voltammetry for physicochemical characteristics. All BTT-derivatives were coated by solution-shearing method and fabricated films were characterized by atomic force microscopy (AFM) and 0-20 X-ray diffraction (XRD). To investigate the electrical performance of newly synthesized BTT-derivatives, bottom-gate/top-contact OFETs were fabricated and characterized in ambient conditions. All compounds exhibited p-channel activity and especially, the resulting OFETs based on films of compound 3 showed the highest hole mobility of 0.11 cm(2)/Vs and current on/off ratio of 8.7 x 10(6).