BEHP-PPV and P3HT blends for light emitting devices

Photoluminescence (PL) and electroluminescence (EL) emissions from blended films composed by Poly[2-(2′,5′-bis(2′-ethyl-hexyloxy)phenyl)-1,4-phenylenevinylene] (BEHP-PPV) and poly(3-hexylthiophene) (P3HT) conjugated polymers are investigated. A PL broad emission spectrum within the visible range was obtained for the BEHP-PPV/P3HT blends. The electroluminescence (EL) spectra of light emission devices fabricated with the blended films with 50% and 25% relative concentration of P3HT present a similar broad emission but shifted to higher wavelengths with increasing applied bias. This tuning capacity was interpreted as due to a change in the effective gap of the blended system caused by the redistribution of injected carriers in the BEHP-PPV/P3HT interfaces of the blend under bias.