The use of urea as an N‐doping 3D hierarchical preserving agent for titanium dioxide nanostructures tailored for dye‐sensitized solar cells

Abstract

Earlier research found that 3D morphologies developed using a low-cost microwave synthesis technique were not retained during the transformation of titanium dioxide (TiO 2 ) by annealing titanium glycerolate (TGy) powder resulting in low photoelectron conversion efficiencies in dye-sensitized solar cell (DSSCs) devices. This study overcame the challenge, and FESEM imaging showed that 3D morphologies were retained after annealing via the same microwave method and the solvent system by using urea as an aid for a structure-preserving/structure-tuning agent. The morphological tuning and N-doping resulted in the 3D hierarchical titanium dioxide nanostructures, including Gomphrena globosa flower-like and blossomed flower of Dahlia pinnata-like morphologies, and other 3D features. The diffusion of N in the TiO 2 matrix was confirmed from XPS and EDX and was also reflected in optical absorption characteristics. The binder-free TiO 2 pastes have been prepared from the synthesized TiO 2 nanopowders that were employed in the screen printing. The screen-printed photoanodes were used to assemble DSSC devices. The output performances of DSSC reveal the influence of the nitrogen doping in relation to the undoped TiO 2 -based device. The G globosa flower-like TiO 2 nanostructured photoanode exhibited the most pronounced enhancement in short-circuit current density and an increase in the maximum power conversion efficiency, by nearly a factor of 2 compared to pure TiO 2 .

Advanced photocatalytic materials based degradation of micropollutants and their use in hydrogen production – a review

“…Furthermore, these energy levels serve to decrease the recombination rate of photogenerated charge carriers by acting as trapping centres for photogenerated electrons. 139,140 Substituting non-metal elements with oxygen (O) atoms in TiO 2 was initially thought to primarily impact the VB, dominated by O, 2p states. However, it's apparent that non-metal doping can also inuence the CB, mainly composed of Ti 3d states.…”

“…Furthermore, these energy levels serve to decrease the recombination rate of photogenerated charge carriers by acting as trapping centres for photogenerated electrons. 139,140 …”

Efficiency and stability improvement of natural dye‐sensitized solar cells using the electrospun composite of TiO 2 nanofibres doped by the bio‐Ca nanoparticles

“…12 In the past two decades, several strategies have been developed to optimize TiO 2 film that can be partitioned into two paths; control the morphology and modification of the TiO 2 nanostructures composition. The most effective procedures to modify nanocrystalline TiO 2 particles consist of TiCl 4 post-treatment, 13,14 surface coating, 15,16 and ions doping. 17,18 The ions doping can effectively modulate the electrical and optical properties through bandgap engineering.…”