Y. Yang et Qb. Pei, LIGHT-EMITTING ELECTROCHEMICAL-CELLS FROM A BLEND OF P-TYPE AND N-TYPE LUMINESCENT CONJUGATED POLYMERS, Applied physics letters, 70(15), 1997, pp. 1926-1928
We demonstrate polymer light-emitting electrochemical cells (LECs) mad
e of a blend of p- and n-type luminescent conjugated polymers. These t
wo polymers, poly[9-(3,6,9-trioxadecyl)-carbazole-3,6-diyl] (TOD-PC, a
p-type polymer) and poly[2,3-di(p-tolyl)-quinoxaline-5,8-diyl] (DT-PQ
X, a n-type polymer), are blue and blue-green emission polymers, respe
ctively, both with high photoluminescent quantum efficiency. However,
the photoluminescence of the polymer blend is completely quenched, due
to the charge transfer between the two polymers. A new and faint oran
ge-yellow photoluminescence emission, which has photonic energy consis
tent with the energy difference of the pi band of TOD-PC and the pi a
nd of DT-PQX, has been observed. LECs fabricated from this polymer ble
nd show strong current injection and bright electroluminescence at thi
s new emission color, which is believed to be due to the interpolymer
radiative recombination of the electrons from the n-type polymer and h
oles from the p-type polymer. Such an independent p doping of TOD-PC a
nd n doping of DT-PQX in the blend and interpolymer radiative recombin
ation provide an interesting way of generating new emission colors in
the LEC system. (C) 1997 American Institute of Physics.