Optical modeling-assisted characterization of dye-sensitized solar cells using TiO₂ nanotube arrays as photoanodes

Abstract

SummaryPhotovoltaic characteristics of dye-sensitized solar cells (DSSCs) using TiO2 nanotube (TNT) arrays as photoanodes were investigated. The TNT arrays were 3.3, 11.5, and 20.6 μm long with the pore diameters of 50, 78.6, and 98.7 nm, respectively. The longest TNT array of 20.6 μm in length showed enhanced photovoltaic performances of 3.87% with significantly increased photocurrent density of 8.26 mA·cm−2. This improvement is attributed to the increased amount of the adsorbed dyes and the improved electron transport property with an increase in TNT length. The initial charge generation rate was improved from 4 × 1021 s−1·cm−3 to 7 × 1021 s−1·cm−3 in DSSCs based on optical modelling analysis. The modelling analysis of optical processes inside TNT-based DSSCs using generalized transfer matrix method (GTMM) revealed that the amount of dye and TNT lengths were critical factors influencing the performance of DSSCs, which is consistent with the experimental results.

One-Dimensional TiO2 Nanostructured Photoanodes: From Dye-Sensitised Solar Cells to Perovskite Solar Cells

“…The proportional increase in NT lengths can be attributed to the continuous oxidation of Ti foil, whereas the decrease in tube wall thickness is due to chemical dissolution of the oxide. In Figure 10c, well-oriented TiO2 NT arrays are observed over the large area of Ti foil substrates with the uniform growth of lengths and pore diameters, and those TiO2 NT arrays can directly be employed as the photoanodes of solar cells without further fabrication processes [14,24].…”

“…Despite the lower amount of adsorbed dyes of the TiO2 NT-based, Jsc of the TiO2 NT-based was higher than that of the TiO2 NP-based, indicating a higher performance of the TiO2 NT-based that could be attributed to their higher light harvesting efficiency by the internal light scattering of TiO2 NT arrays. Meanwhile, Yun and co-workers [24] reported an investigation on optical modelling of DSCs with different thicknesses of TiO2 NT layers of 3.3 μm, 11.5 μm, and 20.6 μm via the generalised transfer matrix (GTMM) method. Based on the optical modelling, short 3.3 μm thick TiO2 NT-based DSCs presented relatively low light absorption with fluctuating light fraction intensity, while thicker TiO2 NTs with 11.5 μm and 20.6 μm showed significantly decreased reflectance results with the increased light absorption, followed by the higher charge generation rate with the increase in thickness of TiO2 NT ( Figure 3) [24].…”

“…Meanwhile, Yun and co-workers [24] reported an investigation on optical modelling of DSCs with different thicknesses of TiO2 NT layers of 3.3 μm, 11.5 μm, and 20.6 μm via the generalised transfer matrix (GTMM) method. Based on the optical modelling, short 3.3 μm thick TiO2 NT-based DSCs presented relatively low light absorption with fluctuating light fraction intensity, while thicker TiO2 NTs with 11.5 μm and 20.6 μm showed significantly decreased reflectance results with the increased light absorption, followed by the higher charge generation rate with the increase in thickness of TiO2 NT ( Figure 3) [24]. Besides vertically-oriented TiO2 NTs, even randomly-oriented TiO2 NWs led to intensive light scattering by the bundles of TiO2 NWs, thereby improving the optical absorption of the photoanodes Besides vertically-oriented TiO 2 NTs, even randomly-oriented TiO 2 NWs led to intensive light scattering by the bundles of TiO 2 NWs, thereby improving the optical absorption of the photoanodes (Figure 4).…”

Light soaking effect driven in porphyrin dye-sensitized solar cells using 1D TiO2 nanotube photoanodes

“…Compared with the conventional DSSCs consisting in mesoporous TiO 2 nanoparticles, vertically well-ordered TiO 2 nanotube (TNT)-based DSSCs showed improved charge collection by efficiently suppressing the recombination of photogenerated electron-hole pairs through minimizing the concentration of trapping sites, which are normally located in the grain boundaries of randomly aggregated TiO 2 particulate films [11][12][13][14]. Thus, a unique structural property of TiO 2 leads to the improved charge transport property, resulting in increased the power conversion efficiency [15][16][17][18][19].…”