Enhancing the Contact Area of Ti Wire as Photoanode Substrate of Flexible Fiber-Type Dye-Sensitized Solar Cells Using the TiO2 Nanotube Growth and Removal Technique.

Mao-Shen Tien,Siao-Ting Hong,Lu-Yin Lin,Bing-Chang Xiao

doi:10.3390/nano9111521

Mao-Shen Tien, Siao-Ting Hong + Show 2 more

Open Access

https://doi.org/10.3390/nano9111521

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Abstract

The fiber-type dye-sensitized solar cell (FDSSC) with flexible and dim-light workable features is one of the promising energy generation devices for soft electronics. A novel TiO2 nanotube (TNT) growth and removal technique is proposed in this study to enhance the contact area of the Ti wire substrate using anodization and ultrasonication processes. Smaller and denser imprints of TNT on the surface of Ti wire are obtained when a smaller voltage was applied for anodization. The thickness of the TiO2 nanoparticle layer coated on the Ti wire is also optimized by varying the dip-coating layers. With the smallest diameter and densest distribution of TNT imprints on the Ti wire, the FDSSC with the TiO2/TNT-printed Ti wire photoanode, prepared using 30 V as the anodization voltage, shows the highest photon-to-electricity efficiency of 2.37% as a result of the rough surface of Ti wire substrate, which provides more contact, as well as the suitable thickness of the TiO2 nanoparticle layer, which promotes charge generation and transportation. The smallest charge-transfer resistance and the highest electron collection efficiency are also obtained in this case, as examined using the electrochemical impedance spectroscopy and intensity modulated photocurrent spectroscopy/intensity modulated photovoltage spectroscopy. This facile TNT growth and removal technique is expected to be able to be applied to other fields for enhancing the contact area of the titanium substrate and promoting the generation of electrochemical reactions.

Highlights

Soft electronics are developed intensively nowadays to facilitate safer and more comfortable lives for modern people [1,2,3]
The VOC and JSC values of the fiber-type dye-sensitized solar cell (FDSSC) increased with thicker TiO2 nanoparticles (TNP) layers and achieved the largest values with three TNP layers
The increases in the JSC value for the FDSSC with thicker TNP layer is attributed to more electron excitation with more dye molecules adsorbed on thicker TNP layers

Summary

Introduction

Soft electronics are developed intensively nowadays to facilitate safer and more comfortable lives for modern people [1,2,3]. Due to the larger surface area of substrate for the counter electrode, a better catalytic ability for redox reactions in electrolyte was achieved and, higher power conversion efficiency was obtained for the resulting DSSC Based on this concept, the surface area of Ti wire and contact between the TNP layer and the Ti wire substrate are expected to be enhanced by using the unique TNT growth-removal technique for facilitating charge transfer. Electrochemical impedance spectroscopy and intensity modulated photocurrent spectroscopy/intensity modulated photovoltage spectroscopy (IMPS/IMVS) were applied to analyze charge-transfer resistance and collection efficiency of fiber-type dye-sensitized solar cell (FDSSC) to further understand effects of the TNT-growth-removal treatment on the photovoltaic performance of FDSSCs

Experimental

Assembly of Fiber-Type Dye-Sensitized Solar Cells

Material Characterizations and Electrochemical Measurements

Results and Discussion