Incorporation of Carbon Dots on the ZnO Nanosheets as Metal–Organic Framework Photoanodes for High Efficient Dye Sensitized Solar Cell Applications

Abstract

In this report, fabrication of carbon dots (CDs) incorporated zinc oxide (ZnO) nanosheets were synthesized by a facile hydrothermal route. The morphology and particles sizes of the ZnO are significantly improved by CDs, which is investigated using XRD, SEM and TEM studies. TEM studies further illustrate that CDs dots with individual spherical shaped with sizes in the ranges 10–15 nm, which is uniformly coated on the surface of the ZnO nanosheets. The textural properties of the CDs/ZnO are dramatically improved due to their high surface area (93.5 m2/g) and porous nature (22.54 nm), which is higher than bare ZnO (43.5 m2/g and 47.31 nm). The assembled device (sandwich type) consists of photoanode (CDs/ZnO), counter electrode (Pt) and iodide/triiodide (I−/I3−). Sun stimulator (AM 1.5G, 100 mW/cm2) used as source of light to evaluate the photovoltaic characteristics. Owing to the huge surface area and porous nature of the CDs/ZnO photoanode show outstanding power conversion efficiency of 7.85%, this is 3.2 times better than bare ZnO photoanode (2.45%). The fabulous behavior is due to the reducing the charge recombination process at the electrode interface.