Charged Defects in a Highly Emissive Organic Wide Bandgap Semiconductor

A new combined photoluminescence detected magnetic resonance (PLDMR) and thermally stimulated current (TSC) study of defects in wide bandgap para-phenylene type semiconductors is described. As TSC probes the density of mobile charge carriers after detrapping and PLDMR reveals the influence of trapped charges on the PL, their combination yields the concentration of traps, their energetic position, and their contribution to PL quenching. The reported trap densities which are 2x10^16 for the polymer and 10^14 cm^-3 for the oligomer are the lowest reported for para-phenylene type materials.