Plasmonic Au NPs embedded Ytterbium-doped TiO2 nanocomposites photoanodes for efficient indoor photovoltaic devices

Abstract

Herein, we present an all-inclusive investigation on the effect of plasmonic gold nanoparticles (Au NPs) embedded Yb-doped TiO2 nanostructured photoanode for efficient photovoltaics devices. Optimally doped Yb (0.5 mol%)-TiO2 nanoparticles (NPs) were synthesised by solid-state grinding. Their structural, morphological, optical, and surface properties were evaluated using XRD, Raman spectroscopy, SEM-EDX, UPS, and XPS. Results show that Yb-doped TiO2 NPs form, reducing the rutile phase and shifting the fermi level. After demonstrating the enhanced properties of Yb-doped TiO2 NPs, we introduced single anatase phase nanowire structures for comparison. Dielectric measurements show Yb-doped TiO2 NW's higher conductivity. Plasmon-induced enhancement of light absorption is achieved by implanting Au NPs into Yb-doped TiO2 NW for additional light harvesting. As a proof of concept, optimised Yb-doped TiO2 photoanode DSSC were fabricated and tested under the AM1.5, 1 sun illumination exhibiting photoconversion efficiency (PCE) of 6 %. Devices employing Yb-doped TiO2 NW: Au NPs photoanode exhibited Jsc to 18.8 % mA-cm−2 and PCE% to 8 %. Under white LED (1000 LUX) exhibited PCE of 13.9 % for Au/Yb-TiO2 NW photoanode. The electrochemical impedance spectroscopy (EIS) measurements on these devices established the Yb-doped TiO2 NW: Au NPs photoanode based device exhibited the lowest charge transport resistance (R2:86 Ω) and charge recombination resistance (R3:20 Ω) which are consistent with the J-V characteristics suggesting the potential use of these photoanode for indoor photovoltaics (IPV) and in general any devices for allied energy and environmental areas of research.