New Unsymmetrically Substituted Benzothiadiazole-Based Luminophores: Synthesis, Optical, Electrochemical Studies, Charge Transport, and Electroluminescent Characteristics

Synthesis of 5-(Aryl)amino-1,2,3-triazole-containing 2,1,3-Benzothiadiazoles via Azide-Nitrile Cycloaddition Followed by Buchwald-Hartwig Reaction

An efficient access to the novel 5-(aryl)amino-1,2,3-triazole-containing 2,1,3-benzothiadiazole derivatives has been developed. The method is based on 1,3-dipolar azide-nitrile cycloaddition followed by Buchwald-Hartwig cross-coupling to afford the corresponding N-aryl and N,N-diaryl substituted 5-amino-1,2,3-triazolyl 2,1,3-benzothiadiazoles under NHC-Pd catalysis. The one-pot diarylative Pd-catalyzed heterocyclization opens the straightforward route to triazole-linked carbazole-benzothiadiazole D-A systems. The optical and electrochemical properties of the compound obtained were investigated to estimate their potential application as emissive layers in OLED devises. The quantum yield of photoluminescence (PLQY) of the synthesized D-A derivatives depends to a large extent on electron-donating strengths of donor (D) component, reaching in some cases the values closed to 100%. Based on the most photoactive derivative and wide bandgap host material mCP, a light-emitting layer of OLED was made. The device showed a maximum brightness of 8000 cd/m2 at an applied voltage of 18 V. The maximum current efficiency of the device reaches a value of 3.29 cd/A.

Photoconduction and Electroluminescence of Copper (II) Protoporphyrin and Chlorin Cu-C-e6

Cu (II) protoporphyrin Cu-PP-IX and chlorin Cu-C-e6 were found to have both thin solid film formation and charge carrier transport abilities. In the layers deposited by resistive thermal evaporation, the mobilities of holes and electrons are on the order of 10^-5 cm² V^-1 s^-1. Organic light-emitting diodes incorporating the dye molecules as emitting dopants demonstrate electroluminescence in the UV and near-IR ranges.