Efficient light harvesting and carrier transport in PbS quantum dots/silicon nanotips heterojunctions

Abstract

Light harvesting from nanocomposites consisting of silicon (Si) nanotips and PbS quantum dots (QDs) has been investigated. We show that Si nanotips provide direct carrier transport paths, additional interfacial area and light trapping. We observe that there is a dramatic enhancement in short-circuit current (from 9.34 to 14.17 mA cm −2 ) with nanotips structure than that of the bulk Si wafer. In addition, with an additional electron blocking layer, the photovoltaic performance can be further increased. The nanocomposites consisting of QDs and Si nanotips therefore open a promising route for efficient light harvesting from visible to infrared with improved power conversion efficiency.