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)mCar₁(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 WCl6Ph4Sn 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 (<400C). 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 438cdm-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.