Carbazole-Functionalised Poly(1-phenyl-1-alkyne)s: Synthesis, Light Emission, and Fluorescent Photopatterning

Carbazole-containing 1-phenyl-1-alkynes with different spacer lengths [C6H5C=C(CH2)mCar 1(m) (m = 3, 4, 9), Car =9-carbazolyl] were synthesised in high yields by consecutive substitution and coupling reactions of n-chloro-1-alkynes. Polymerisation of the monomers was effected by NbCl5– and WCl6–Ph4Sn catalysts, furnishing soluble polymers P1(m) with high molecular weights in high yields. All the polymers were thermally stable, commencing to lose their weights at high temperatures (= 400°C). Photoexcitation of their THF solutions induced strong blue light emissions with high quantum efficiencies up to 92 %. Multilayer electroluminescence devices with configurations of ITO/P1(m)(:PVK)/BCP/Alq3/LiF/Al were constructed, which gave blue light with maximum luminance and external quantum efficiency of 438 cd m–2 and 0.63 %. UV irradiation of a thin film of P1(4) through a mask oxidized and quenched the light emission of the exposed parts, generating a two-dimensional luminescent photopattern.