Efficient electron transport in tetrapod-like ZnO metal-free dye-sensitized solar cells

Chiu, Wei‐Hao; Lee, Chia-Hua; Cheng, Hsin‐Ming; Lin, Hsueh-Yi; Liao, Shih‐Chieh; Wu, Jenn‐Ming; Hsieh, Wen–Feng

doi:10.1039/b902595m

Cited by 79 publications

(25 citation statements)

References 19 publications

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“…Chiu [73] reported a photoanode film composed of tetrapod-like ZnO nanoparticles, which were fabricated by a DC plasma method with D149 dye. The film provided good electron transport and light harvesting to achieve a conversion efficiency as high as 4.9%.…”

Section: Usage Of Zno Nanotetrapods As Photoanodic Materials In Dsscsmentioning

confidence: 99%

ZnO Tetrapods: Synthesis and Applications in Solar Cells

Yan

Uddin

Wang

2015

Nanomaterials and Nanotechnology

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Zinc oxide (ZnO) tetrapods have received much interest due to their unique morphology, that is, four arms connected to one centre. Tetrapod networks possess the excellent electronic properties of the ZnO semiconductor, which is attractive for photoelectrode materials in energyconversion devices because of their advantages in electron extraction and transportation. In this review, we have discussed recent advancements in the field of ZnO tetrapod synthesis, including vapour transport synthesis and the wet chemical method, together with their advantages and disadvantages in terms of morphology control and yield regulation. The developments and improvements in the applications of ZnO nanotetrapods in photovoltaics, including dye-sensitized solar cells and polymer solar cells, are also described. Our aim is to give readers a comprehensive and critical overview of this unique morphology of ZnO, including synthesis control and growth mechanism, and to understand the role of this particular morphology in the development of solar cells. The future research directions in ZnO tetrapods-based solar cell are also discussed.

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Section: Usage Of Zno Nanotetrapods As Photoanodic Materials In Dsscsmentioning

confidence: 99%

ZnO Tetrapods: Synthesis and Applications in Solar Cells

Yan

Uddin

Wang

2015

Nanomaterials and Nanotechnology

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“…However, it represents a significant improvement over the best DSSC based on a well-aligned ZnO nanorod array photoanode: about 60% higher in J sc mainly due to a higher RF of our nanotetrapods film (350 for the about 30 μm thick nanotetrapods film versus 200 for the 20 μm thick nanorod arrays film), about 50% higher in FF, and as a consequence nearly 120% higher in overall efficiency [13]. A higher efficiency was reported subsequently by Chiu et al on a similar system primarily thanks to their use of an organic D149 dye with higher extinction coefficient, in addition to the necessary calcination procedure [28]. Figure 2(b) plots the amount of dye loading versus the nanotetrapod film thickness and RF, which are related by a proportionality factor.…”

Section: Zno Nanotetropod Photoanodementioning

confidence: 60%

“…This result demonstrates the long effective electron diffusion length of the ZnO nanotetrapods films and explains why J sc of our nanotetrapods DSSCs is still below the saturation point even when the film thickness has been increased up to > 20 μm. Such a long effective diffusion length has also been verified by Chiu et al [28]. …”

Section: Zno Nanotetropod Photoanodementioning

confidence: 61%

“…This was the first time that DSSC based on pure ZnO nanotetrapod photoanode was demonstrated with a reasonable efficiency; simply by physically contacting the nanotetrapods, the branched nanotetrapods network could effectively transport photoinduced electrons. Later on, Chiu et al [28] and Bacsa et al [29] also reported studies on ZnO nanotetrapods based DSSCs with their photoanodes all calcined at high temperatures.…”

Section: Introductionmentioning

confidence: 96%

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Dye-sensitized solar cells based on ZnO nanotetrapods

Chen

Yang

2011

Front. Optoelectron. China

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In this paper, we reviewed recent systematic studies of using ZnO nanotetrapods for photoanodes of dye-sensitized solar cells (DSSCs) in our group. First, the efficiency of power conversion was obtained by more than 3.27% by changes of conditions of dye loading and film thickness of ZnO nanotetrapod. Short-circuit photocurrent densities (J sc ) increased with the film thickness, J sc would not be saturation even the film thickness was greater than 35 μm. The photoanode architecture had been charactered by good crystallinity, network forming ability, and limited electron-hopping interjunctions. Next, DSSCs with high efficiency was devised by infiltrating SnO 2 nanoparticles into the ZnO nanotetrapods photoanodes. Due to material advantages of both constituents described as above, the composite photoanodes exhibited extremely large roughness factors (RFs), good charge collection, and tunable light scattering properties. By varying the composition of the composite photoanodes, we had achieved an efficiency of 6.31% by striking a balance between high efficiency of charge collection for SnO 2 nanoparticles rich films and high light scattering ability for ZnO nanotetrapods rich films. An ultrathin layer of ZnO was found to form spontaneously on the SnO 2 nanoparticles, which primarily was responsible for enhancing open-circuit photovoltage (V oc ). We also identified that recombination in SnO 2 /ZnO composite films was mainly determined by ZnO shell condition on SnO 2 , whereas electron transport was greatly influenced by the morphologies and sizes of ZnO crystalline additives. Finally, we applied the composite photoanodes of SnO 2 nanoparticles/ZnO nanotetrapods to flexible DSSCs by low temperature technique of "acetic acid gelation-mechanical press-ammonia activation." The efficiency has been achieved by 4.91% on ITO-coated polyethylenenaphtalate substrate. The formation of a thin ZnO shell on SnO 2 nanoparticles, after ammonia activation, was also found to be critical to boosting V oc and to improving inter-particles contacts. Mechanical press, apart from enhancing film durability, also significantly improved charge collection. ZnO nanotetrapods had been demonstrated to be a better additive than ZnO particles for the improvement of charge collection in SnO 2 /ZnO composite photoanodes regardless of whether they were calcined.

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“…4 New strategies are being developed to upgrade the DSCs performances such as the application of new ZnO nanostructures (tetrapods, nanotubes, nanosheets, nanoparticles (NPs) aggregates, among others), which allowed a 6% e±ciency. [5][6][7] Another alternative path to increase the DSCs performances is the use of ZnO core-shell nanostructures to improve surface structure. 8,9 Nevertheless, the instability of ZnO is observed when the dye attaches to the ZnO surface through the carboxylic acid group decreasing the solar cell e±ciency.…”

Section: Introductionmentioning

confidence: 99%

Vertically Aligned ZnO/In_xS_y Core–Shell Nanorods for High Efficient Dye-Sensitized Solar Cells

González-Valls

Ballesteros

Lira‐Cantú

2015

NANO

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Innovative vertically aligned ZnO/In x S y nanorod (NR) electrodes were prepared by successive ion layer adsorption and reaction (SILAR) technique. The In x S y shell layer was deposited on top of ZnO NR electrodes of two di®erent lengths, $ 1:6 m and $ 3:2 m. Two sulfur contents on the In x S y shell layer with di®erent layer thicknesses were analyzed. These electrodes were fully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray di®raction spectroscopy (XRD), Energy-dispersive x-ray spectroscopy (EDS), Infrared spectroscopy (FT-IR), x-ray photoelectron spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS) and then applied in dye-sensitized solar cells (DSC). Power conversion efciency of 2.32% was observed when a low-sulfur content In x S y shell layer was applied in comparison to the stoichiometric In 2 S 3 shell layer (0.21%) or the bare ZnO NRs (0.87%). In the case of low sulfur content, a shell layer of In(OH) x S y or/and In(OH) 3 is formed as observed by the presence of -OH observed by FTIR analyses. The presence of higher amounts of hydroxide groups modi¯es the bandgap and work function of the In x S y shell and facilitates dye adsorption, increasing the¯nal solar cell performance.

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Efficient electron transport in tetrapod-like ZnO metal-free dye-sensitized solar cells

Cited by 79 publications

References 19 publications

ZnO Tetrapods: Synthesis and Applications in Solar Cells

ZnO Tetrapods: Synthesis and Applications in Solar Cells

Dye-sensitized solar cells based on ZnO nanotetrapods

Vertically Aligned ZnO/In_xS_y Core–Shell Nanorods for High Efficient Dye-Sensitized Solar Cells

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Efficient electron transport in tetrapod-like ZnO metal-free dye-sensitized solar cells

Cited by 79 publications

References 19 publications

ZnO Tetrapods: Synthesis and Applications in Solar Cells

ZnO Tetrapods: Synthesis and Applications in Solar Cells

Dye-sensitized solar cells based on ZnO nanotetrapods

Vertically Aligned ZnO/InxSy Core–Shell Nanorods for High Efficient Dye-Sensitized Solar Cells

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Product

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Vertically Aligned ZnO/In_xS_y Core–Shell Nanorods for High Efficient Dye-Sensitized Solar Cells