Synthesis of π-Conjugated Polymers Containing Benzotriazole Units via Palladium-Catalyzed Direct C-H Cross-Coupling Polycondensation for OLEDs Applications

Abstract

Four D-π-A conjugated polymers, namely P1–P4, which contain benzotriazole building blocks in their backbone as acceptor, are synthesized via palladium-catalyzed direct C-H cross-coupling polycondensation of 5,6-difluorobenzotriazole with different thiophene derivatives, including 3-octylthiophene, 2,2’-bithiophene, thieno[3,4-b][1,4]dioxine, and 4,4-dioctyl-4H-silolo-[3,2-b:4,5-b’]dithiophene as donor units, respectively. Taking the polymer P1 as an example, the chemical structure of the polymer is demonstrated by 1H and 19F NMR spectra. The optical, electrochemical, and thermal properties of these polymers are assessed by UV–vis absorption and fluorescence spectroscopy, cyclic voltammetry (CV), and thermal gravimetric analysis (TGA), respectively. DFT simulations of all polymers are also performed to understand their physicochemical properties. Furthermore, P1 and P2, which have relatively higher molecular weights and better fluorescent quantum efficiency than those of P3 and P4, are utilized as lighting emitters for organic light-emitting diodes (OLEDs), affording promising green and red luminescence with 0.07% and 0.14% of maximum external quantum efficiency, respectively, based on a device with an architecture of ITO/PEDOT:PSS/PTAA/the polymer emitting layer/TPBi/LiF/Al.

High-performance, low-voltage organic field-effect transistors using thieno[3,2-b]thiophene and benzothiadiazole co-polymers

“…Organic semiconducting materials have gained significant attention due to their advantages of easy processability, high mechanical flexibility, high electroactivity and chemical structure tunability in comparison with inorganic semiconductors. 13 These advantages make them promising materials in organic light emitting diodes (OLEDs), [14][15][16][17] organic solar cells, [18][19][20] organic photovoltaics (OPVs) [21][22][23] and organic field-effect transistors (OFETs). [24][25][26][27][28][29][30] OFETs form the basic building blocks of many organic and hybrid electronic devices such as flexible radio-frequency identification tags, large-area sensors and flexible displays, and smart cards and sensors, thus providing an excellent platform for fundamental studies of charge transport in organic semiconductors (OSCs).…”

“…Organic semiconducting materials have gained significant attention due to their advantages of easy processability, high mechanical flexibility, high electroactivity and chemical structure tunability in comparison with inorganic semiconductors. 13 These advantages make them promising materials in organic light emitting diodes (OLEDs), 14–17 organic solar cells, 18–20 organic photovoltaics (OPVs) 21–23 and organic field-effect transistors (OFETs). 24–30…”

Synergy between the Assembly of Individual PEDOT Chains and Their Interaction with Light

“…Liquid-state 1 H hr-NMR spectroscopy was used to investigate the reaction kinetics in the range from 30 min to 48 h for EDOT solution in d 6 -ethanol and d 2 -formic acid (3:7 vol %), see Supporting Information, Figure S1. The representative 1 H NMR spectra are depicted in Supporting Information, Figure S1, and the signal assignment is based on literature data. , We must emphasize that the 1 H NMR peaks are very narrow, which proves that acid-assisted polymerization proceeds without the formation of cation radicals …”

Cross‐Dehydrogenative Coupling Polymerization via C−H Activation for the Synthesis of Conjugated Polymers

“…Recently, Lu and co‐workers have reported CDC polycondensation of 5,6‐difluorobenzotriazole with different thienyl donor units to synthesize a series of alternating copolymers P11‐17 (Scheme 19). [87, 88] The highest number average molecular weight was obtained for P13 ( M n =28.1 kg mol −1 ) with 82 % yield. The same polymer synthesized via Stille coupling had a lower molecular weight ( M n =23.3 kg mol −1 ).…”