Enhanced hole injection in a polymer light emitting diode using a small molecule monolayer bound to the anode

A monolayer of quarterthiophene-2-phosphonate (4TP) bound to indium tin oxide (ITO) was p-doped with tetrafluorotetracyanoquinodimethane (F4-TCNQ) and was used to fabricate simple polymer devices. Poly(2-methoxy-5-[2′-ethylhexyloxy]-p-phenylene vinylene) (MEH-PPV) and Al served as the electroluminescent polymer and the cathode, respectively. These devices can perform better, current-wise, than ones using poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid), PEDOT:PSS.