Design of Multilayers of Urchin-like ZnO Nanowires Coated with TiO₂Nanostructures for Dye-Sensitized Solar Cells

Abstract

In dye-sensitized solar cells, the photovoltaic efficiency of nanowires (NW) is still limited by their surface area and loss of light absorption compared with nanoparticle (NP) architectures. To overcome this limitation, the light harvesting efficiencies must be improved by increasing the total NW array surface area, without increasing too much the traveled distance of electrons.Here, we describe the design of a 3D architecture based on polystyrene spheres (PS) coated with ordered multilayers of urchin-like ZnO NWs (U-ZnO NWs) to be used as a high surface area nanostructure photoanode for dye-sensitized solar cells. Two to four layers of U-ZnO NWs were synthesized by using PS of 1 and 5 µm in diameter. The ordered layers of U-ZnO NWs were then coated with a thin layer of TiO2 by atomic layer deposition, and topped with a ~ 9-14 µm thick layer of anatase TiO2 NPs. We found that assembling organized layers of U-ZnO NWs significantly increased the surface area and provided better photon absorption. Moreover, coating the U-ZnO NWs with a thin TiO2 layer decreased the charge recombination and consequently enhanced the photovoltaic efficiency.

Design of Morphology-Controllable ZnO Nanorods/Nanopariticles Composite for Enhanced Performance of Dye-Sensitized Solar Cells

“…For instance, Galoppini et al compared the electron transport properties of the photoanodes based on ZnO NRs array and colloids, and noticed that electron transport in the device with ZnO NRs photoanode was approximately 2-fold faster than that in ZnO colloids [20]. Besides, Kretzschmar et al observed that the electron lifetime in photoanode films fabricated with NRs was 2 times longer compared to that with nanoparticles [21]. Apart from efficient electron transport, 1-D nanostructures with tunable lengths ranging from hundreds of nanometers to micrometers are also promising light-scattering centers with enhanced optical propagation distance within the films and improved light collection efficiencies [22,23,24].…”

Hoisting the photovoltaic performance by photocharging and plasmonic effect via aminosilane‐protected silver/barium titanate for dye‐sensitized solar cells

“…The conventional DSSCs were made up of TiO 2 ‐based photoanodes due to the high specific surface area and good dye absorption capability 4 . Alternatively, other photoanodes such as ZnO, 5 Nb 2 O 5 , 6 and WO 3 7 has been explored. Recently, oxide perovskites opened up a new era in the area of photocatalysts, 8 capacitors, 9 and sensors 10 owing to its unique properties.…”

Open-Circuit Voltage (VOC) Enhancement in TiO2-Based DSSCs: Incorporation of ZnO Nanoflowers and Au Nanoparticles

“…15,16 These procedures can result in a structure consisting of a blend of ZnO and TiO 2 nanoparticles or a core−shell structure. 17,18 ZnO nanoflowers have also been combined with TiO 2 using different strategies. Prabakar et al 19 grew ZnO nanoflowers directly on fluorinedoped tin oxide (FTO) substrates using hexamethylenetetramine (HMTA) as an additive and coated them with TiO 2 using the sol−gel method, obtaining an efficiency of 3.1% and an increase of around 100 mV in open-circuit voltage (V OC ).…”