Synergistic effects of the aspect ratio of TiO sub(2) nanowires and multi-walled carbon nanotube embedment for enhancing photovoltaic performance of dye-sensitized solar cells

• Published in: Nanoscale 2013-07, Vol.5 (15), p.6842-6850
• Main Authors: Ahn, Ji Young, Kim, Ji Hoon, Moon, Kook Joo, Park, So Dam, Kim, Soo Hyung
• Format: Article
• Language: English
• Subjects: Boundaries
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c3nr01689g

The existence of numerous interfacial boundaries among TiO sub(2) nanoparticles (NPs) accumulated in the photoelectrode layer of dye-sensitized solar cells (DSSCs) hinders the effective transport of photogenerated electrons to an electrode. Therefore, as a replacement for TiO sub(2) NPs, one-dimensional TiO sub(2) nanowires (NWs) can be suggested to provide pathways for fast electron transport by significantly reducing the number of interfacial boundaries. In order to provide direct evidence for the better performance of such longer TiO sub(2) NWs than shorter TiO sub(2) NWs, we examine the effect of the controlled aspect ratio of the TiO sub(2) NWs randomly accumulated in the photoelectrode layer on the photovoltaic performance of DSSCs. It is clearly found that longer TiO sub(2) NWs significantly improve the electron transport by reducing the TiO sub(2)/dye/electrolyte interfacial contact resistance. Furthermore, the embedment of multi-walled carbon nanotubes (MWCNTs) as an effective charge transfer medium in longer TiO sub(2) NWs is proposed in this study to promote more synergistic effects, which lead to significant improvements in the photovoltaic properties of DSSCs.