Green-light emitting norbornene based terbium-containing copolymers. Synthesis, photo- and electroluminescent properties

• New Tb-containing copolymers were synthesized by ROMP of norbornene based monomers.
• Photo- and electroluminescence properties of the copolymers were investigated.
• Max electroluminance of 70 cd/m2 at 17.5 V was achieved.
• CIE coordinates (0.28, 0.47) were independent on driving voltage.

New terbium-containing copolymers were prepared by ring-opening metathesis copolymerization (ROMP) of norbornene substituted terbium complex Tb(L1)2(L2)(TPPO)2 (L1 = 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolonato, L2 = 1-phenyl-3-methyl-4-(5-bicyclo[2.2.1]hept-5-en-2-yl)-5-pyrazolonato, TPPO = triphenylphosphine oxide) and carbazole-containing norbornene derivatives. The photoluminescence (PL) spectra of the copolymers contained strong narrow bands of terbium ion at 492 (5D4 → 7F6), 550 (5D4 → 7F6), 586 (5D4 → 7F4), 624 (5D4 → 7F3) nm and emission in the region of 350-450 nm assigned to copolymer matrixes. The electroluminescence (EL) spectrum of the tree-layer device of configuration of ITO/Tb-copolymer(40 nm)/BATH(30 nm)/Alq3(30 nm)/Yb revealed intense emission bands of Tb(III) ions and a broad band at ca. 520 nm of low intensity attributed to emission from triplet level of carbazole groups. The maximum luminance of 70 cd/m2 at 17.5 V, the maximum current efficiency of 0.56 cd/A at 11 V and the maximum power efficiency of 0.16 lm/w at 11 V were achieved. The CIE coordinates (0.28, 0.47) were corresponded to green color and independent on driving voltage.

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