S, N Co-Doped Graphene Quantum Dots Decorated C-Doped ZnO Nanotaper Photoanodes for Solar Cells Applications

Abstract

Sulfur and nitrogen co-doped graphene quantum dots (SNGQDs) were synthesized using a hydrothermal method. The doping of S, N atoms and chemical bonding in SNGQDs has been investigated by XPS measurements. Our as-grown SNGQDs showed strong UV (wavelength [Formula: see text]261–341[Formula: see text]nm) and visible absorption (wavelength [Formula: see text]261–341[Formula: see text]nm) and demonstrated excitation-dependent photoemission in visible spectrum. Photoelectrochemical and photovoltaic properties of SNGQDs sensitized carbon-doped ZnO nanotaper (C-ZnO NT) photoanodes has been studied in detail. SNGQD sensitized photoanodes demonstrated superior photoconversion efficiency ([Formula: see text]1.46% and incident-photon-to-current conversion efficiency (IPCE) [Formula: see text]92.48% at 340[Formula: see text]nm. Quantum dot sensitized solar cells (QDSSCs) has been fabricated using SNGQDs sensitized C-ZnO NT photoandoes and demonstrated maximum power conversion efficiency ([Formula: see text]0.59%.