Europium coordination compounds based on carbacylamidophosphate ligands for metal-organic light-emitting diodes (MOLEDs)

Abstract

In this work, the photo- and electroluminescence properties of new red phosphores based on europium complexes with carbacylamidophosphate (CAPh) ligands and additional aromatic ligands 1,10-phenantroline and 4,4'-bipyridine have been studied. Compounds Eu(L¹)₃(phen) (1), Eu(L²)₃(phen) (2), Eu2(L¹)₆(i-prOH)²(4,4'-bipy) (3) and Eu²(L²)₆(H2O)²(4,4'-bipy) (4), where HL – 2,2,2-trichloro-N-(dipiperidin-1-ylphosphoryl) acetamide, HL² – 2,2,2-trichloro-N-(dimorpholin-1-ylphosphoryl)acetamide, were synthesized. Technology of europium complexes coating from solutions with different concentrations in different solvents has been developed. Experimental samples of light-emitting planar heterostructures were fabricated using the device architecture comprising an anode (ITO), a hole transport layer of 1,4- Bis(diphenylamino)benzene (BDB), a layer of complex and a cathode (Al or Mg). Another heterostructure configuration with a hole-transport layer of poly(3,4- ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) has also been investigated. The different types of planar heterostructures were prepared, and their current-voltage characteristics have been discussed.