Hybrid Silicon Nanocrystal/Poly(3-hexylthiophene-2,5-diyl) Solar Cells from a Chlorinated Silicon Precursor

Abstract

Freestanding silicon nanocrystals (Si NCs) synthesized by a nonthermal plasma from silicon tetrachloride (SiCl 4 ) were successfully employed in hybrid Si NC/poly(3-hexylthiophene-2,5-diyl) (P3HT) bulk-hetrojunction (BHJ) solar cells. The weight fraction of Si NCs in P3HT greatly influences device performance. As the weight fraction increases up to 50 wt %, short-circuit current dramatically increases, while open-circuit voltage ( V oc ) and fill factor ( FF ) do not change significantly. The improvement in device performance is attributed to both increased probability of exciton dissociation in P3HT and an enhancement in the light conversion of wavelengths where P3HT is a poor absorber. These results demonstrate an alternative approach to synthesizing Si NCs from SiCl 4 instead of silane (SiH 4 ) for optoelectronic devices.