Luminescent properties of doped freestanding silicon nanocrystals embedded in MEH-PPV

We demonstrate that the electrochemical etching and pulverization of porous silicon films allow the fabrication of boron- and phosphorous-doped freestanding silicon nanocrystals (Si-ncs). The presence of boron in freestanding Si-ncs was confirmed from low-temperature photoluminescence (PL) analysis. The temperature dependence of PL for both types of doped Si-ncs reveals two PL bands due to the quantum confinement effect and surface state defects. Blending of Si-ncs into poly[methoxy-ethylexyloxy-phenylenevinilene] polymer leads to suppression of the PL band originated from surface states. More importantly, those blends showed a photoconductivity response under illumination AM1.5 at room temperature.