Light Emitting Electrochemical Cell
The present invention relates to multi-layered light emitting electrochemical cell (LEC) and preparation thereof. The present invention also relates to the composition of the light emitting layer (3) of a light emitting electrochemical cell (LEC). The light emitting layer (3) of the light emitting electrochemical cell consists of a neutral polymer and a pyridinium luminophore. The pyridinium luminophores used are non-polymeric small molecule compounds.
1 . A multi-layered light emitting electrochemical cell (LEC) comprising
a light emitting layer, the light emitting layer being placed between
a transparent anode layer entirely covering said light emitting layer (3), and
a cathode layer;
wherein the light emitting layer comprises a pyridinium luminophore.
2 . The multi-layered light emitting electrochemical cell according to claim 1 , wherein the light emitting layer further comprises a neutral polymer.
3 . The multi-layered light emitting electrochemical cell according to claim 2 , wherein the neutral polymer is poly(methyl methacrylate) or poly(ethylene oxide).
4 . The multi-layered light emitting electrochemical cell according to claim 1 , wherein the pyridinium luminiphore is a compound of Formula 1:
wherein
R 1 is an aliphatic group;
R 2 is a neutral or electron donating substituent of the carbazole core with a Hammett σ para constant in the range between −0.90 and 0.23;
L is an aromatic linker; and
X is a negatively charged counter ion selected from NO 3 − , MsO − , ClO 4 − , and Cl − .
5 . The multi-layered light emitting electrochemical cell according to claim 1 , further comprising a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate layer placed between the light emitting layer and the transparent anode layer.
6 . The multi-layered light emitting electrochemical cell according to claim 5 , wherein the thickness of the poly(3,4-ethylenedioxythiophene) polystyrene sulfonate layer is 20 to 70 nm.
7 . The multi-layered light emitting electrochemical cell according to claim 1 , wherein the light emitting layer is 80 to 400 nm thick.
8 . The multi-layered light emitting electrochemical cell according to claim 1 , wherein the pyridinium luminophore is 70 to 100 wt % of the light emitting layer.
9 . The multi-layered light emitting electrochemical cell according to claim 2 , wherein the neutral polymer is 30 to 0 wt % of the light emitting layer.
10 . The multi-layered light emitting electrochemical cell according to claim 1 , wherein the light emitting layer is wet-casted or spin-coated directly onto the anode layer.
11 . The multi-layered light emitting electrochemical cell (LEC) according to claim 1 , wherein the cathode layer is deposited onto the light emitting layer through thermal evaporation in vacuum.