Bright blue electroluminescence from poly(N-vinylcarbazole)

Abstract

Electroluminescent devices were fabricated using poly(N-vinylcarbazole) (PVK) as a hole-transporting emitter layer and a double layer of 1,2,4-triazole derivative (TAZ) and tris(8-quinolinolato)aluminum(III) complex (Alq) as an electron transport layer. A cell structure of glass substrate/indium-tin-oxide/PVK/TAZ/Alq/Mg:Ag was employed. In this cell structure, carrier injection from the electrodes to the PVK layer and concomitant electroluminescence from PVK were observed. Blue emission peaking at 410 nm and a luminance of 700 cd/m2 were achieved at a drive voltage of 14 V.

The nature of trapping sites and recombination centres in PVK and PVK–PBD electroluminescent matrices seen by spectrally resolved thermoluminescence

“…In all the cases, a broad and unstructured emission band extending from 350 nm to over 650 nm, with a dominant broad maximum at 420-445 nm, was observed [6][7][8][9]. The emission at ca 420-430 nm comes from the low energy singlet excimer (full overlap carbazole units).…”

“…It is worth to note that up to now the excimeric phosphorescence in the PVK films was related to the emission in the range 480-530 nm; however lower energetic tail down above 650 nm was observed in both phosphorescence and EL spectra [6,8]. This emission bands about 590 nm and above 600 nm were attributed to several different mechanisms, such as aggregation, [7,9] electroplex [3,9] or phosphorescence [13,14].…”

Tuning of emission color for blue dendrimer blend light-emitting diodes

“…Poly-N-vinylcarbazole (PVK) has HOMO and LUMO energies of 5.5 and 2.0 eV, respectively. 17 A PVK layer between the dendrimer film and anode could therefore be expected both to aid injection of holes and prevent electrons from reaching the anode. The dendrimer film in this configuration acts as the electron transporting and light-emitting layer.…”

Ladder Polysiloxanes for Optoelectronic Applications

“…13, the turn-on voltage of device is 5.8 V, which is lower than that of reported polymer host materials. The device reaches the maximum brightness of 883 cd/m 2 at 13 V and shows a maximum luminous efficiency of 8.7 cd/A or the maximum power efficiency of 3.1 lm/W, which is superior to that of the reported polymer host (9,9 ' -bis(2-ethylhexyl)-3,6-fuorene) (Wu et al, 2008) and PVK, (Kido et al, 1993) even comparable to the small molecule host 4,4 ' -bis(9-carbazolyl)biphenyl (CBP). (Hu et al, 2009) The external quantum of the device is 4.6% ph/el, which is best blue light polymer host for FIrpic reported so far.…”