Browsing by Author "Wang, Ying-Chiao"

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High performance dye-sensitized solar cells based on platinum nanoparticle/multi-wall carbon nanotube counter electrodes: The role of annealing
(2012-04-01)
Huang, Kuan-Chieh
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Wang, Ying-Chiao
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Chen, Po-Yen
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Lai, Yi-Hsuan
;
Huang, Jen-Hsien
A composite film is coated on the FTO using a solution, containing a synthesized dispersant, poly(oxyethylene)-segmented imide (POEM), dihydrogen hexachloroplatinate (H2PtCl6), and multi-wall carbon nanotube(MWCNT); the thus coated FTO is used as the counter electrode (CE) for a dye-sensitized solar cell (DSSC). The annealing temperature of the composite film, in the range of 110-580 degrees C, is found to be crucial for optimizing its catalytic ability to obtain the best possible performance for the DSSC. About 47% loss in mass for the POEM/H2PtCl6/MWCNT composite is observed from 110 to 390 degrees C, due to not only the progressive formation of PtNPs from H2PtCl6 but the decomposition of POEM. Therefore, the efficiencies (eta) of DSSCs applying these CEs are enhanced from 1.28 +/- 0.08% (110 degrees C) to 8.47 +/- 0.21% (390 degrees C). The mass of the composite loses dramatically under heating above 390 degrees C, due to the decomposition of MWCNTs. The eta decreases to 7.77 +/- 0.15% at 450 degrees C because the decrease in surface roughness of film. PtNPs grow in sizes from 450 to 580 degrees C, resulting in the further decrease in catalytic ability of film and the observed eta from 7.77 +/- 0.15% to 7.19 +/- 0.21%. (C) 2011 Elsevier B.V. All rights reserved.
Solution-processed organometallic quasi-two-dimensional nanosheets as a hole buffer layer for organic light-emitting devices
(2020-04-07)
Liu, Shihao
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Wang, Ying-Chiao
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Chang, Chi-Ming
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Yasuda, Takeshi
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Fukui, Naoya
Two-dimensional (2D) vdW materials have been integrated into optoelectronic devices to achieve exceptional functionality. However, the integration of large-area 2D thin films into organic light-emitting devices (OLEDs) remains challenging because of the finite number of inorganic 2D materials and the high-temperature requirements of their deposition process. The construction of 2D organometallic materials holds immense potential because of their solution synthesis and unlimited structural and functional diversity. Here, we report a facile route using an oil-water interfacial coordination reaction between organic ligands and divalent metal ions to synthesize crystalline quasi-2D organometallic bis(dithiolato)nickel (NiDT) nanosheets with a centimeter scale and a tunable thickness. The NiDT nanosheets can be directly integrated into OLEDs for use as a hole buffer layer and a fluorescent mounting medium without the aid of a transfer process. Moreover, OLEDs with NiDT nanosheets show not only comparable efficiency to conventional OLEDs but also prolonged device lifetime by nearly 2 times. These results open up a new dimension to use quasi-2D organometallic nanosheets as functional layers in large-area organic devices.