Lanthanide complexes are long ago recognized as highly luminescent materials. Their luminescence efficiencies – or quantum yields – easily reach 100%. Different classes of lanthanide-based materials can demonstrate this value, but only lanthanide aromatic carboxylates are stable enough to be used as thin films in OLEDs, which will work long and stable.
Unfortunately, they are also non-volatile and insoluble – so how can we make a nanometer-scale thin films from them?
We actually can! Thanks to the new thin film deposition method – we call it MLCFD, or Mixed-Ligand Complex Formation-Decomposition, — developed in Lomonosov Moscow State University, Moscow, Russia, we can obtain these films as thin as 40 nm and even less with the roughness below only 2 nm.
This isenough to use them in the OLED heterosctructure!
The cost of the final product consists of the several factors:
Lanthanides are remarkably cheaper than iridium – but that’s not all. The organic ligands we use are simple and easily synthesized. The complexes are air-stable – so no need to use expensive glove-boxes and Schlenk line for their production.
The MLCFD method allows to use solution deposition to obtain thin films. So the expensive thermal evaporation method is also not needed – you can just print them!