Investigation on synthesis and characterization of ZnO nanostructure photoelectrode for dye-sensitized solar cells

Abstract

The spray pyrolysis technique was utilized to prepare the ZnO nanoparticle-based photoanodes for dye-sensitized solar cells (DSSCs). The particle size in the range of 6–10 nm was synthesized by the sol–gel method using zinc acetate dihydrate ((CH₃COO)₂Zn.2H₂O) and lithium hydroxide monohydrate (LiOH.H₂O). In addition, a novel approach was introduced to synthesis ZnO porous nanostructures via solvo-thermal method. In this method, zinc acetate dihydrate and sodium dodecyl sulfate (SDS) (WAKO CO., LTD) utilized as precursors. The prepared ZnO nanoparticles were characterized by XRD, SEM, and TEM. Dye-sensitized solar cells (DSSCs) were prepared based on synthesized ZnO particle-based photoelectrode and studied their performance. DSSCs prepared based on commercially available ZnO nanoparticle (20 nm) based electrode exhibit a higher conversion efficiency 2.22% compared to 1.42% for mixed (Syn/comm (6:4)) materials. This suggests that commercially manufactured nanoparticles exhibit superior light harvesting and charge transport properties compared to smaller and mixed commercial powders. Further, the effect of thickness on efficiency of DSSCs also extensively investigated. The results reveal that the commercial material efficiency increases 2.2–3.5% with thickness from 12 to 17 µm, indicating better light capture at higher thicknesses. However, we observed that Syn/comm (6:4) material did not exhibit much difference at higher thickness that due to smaller-sized particles it may exhibited less porosity for dye adsorption more boundaries creates lack of connection between particles for electron transportation. However, at lower thickness flexible devices these combination material provide higher efficiency compared to commercially produced materials. Further, SDS-assisted ZnO porous structure material (P-ZnO) was synthesized and investigated electrode performance. The P-ZnO-based electrode cell demonstrated an enhanced efficiency of 4.92%, attributed to increased dye adsorption and efficient electron transfer facilitated by well-connected particles.