Field-induced fluorescence quenching and enhancement of porphyrin sensitizers on TiO2 films and in PMMA films
|Hsu, Hung-Yu; Chiang, Hung-Chu; Hu, Jyun-Yu; Awasthi, Kamlesh; Mai, Chi-Lun; Yeh, Chen-Yu; Ohta, Nobuhiro; Diau, Eric Wei-Guang||2013||Journal of Physical Chemistry C, 2013 ,vol. 117,# 47p. 24761 - 24766|
Molecular engineering of cocktail co-sensitization for efficient panchromatic porphyrin-sensitized solar cells
Co-sensitization of two or more dyes with complementary absorption spectra on a semiconductor film is an effective approach to enhance the performance of a dye-sensitized solar cell (DSSC). Porphyrin sensitizer YD2-oC8 showed outstanding photovoltaic performance co-sensitized with an organic dye to cover the entire visible spectral region, 400-700 nm. To promote the light-harvesting capability beyond 700 nm, a porphyrin dimer (YDD6) was synthesized for a co-sensitized system. We report a systematic approach for engineering of molecular co-sensitization of TiO2 films in a cocktail solution containing YD2-oC8, an organic dye (CD4) and YDD6 in a specific molar ratio to optimize the photovoltaic performance of the device. The resulting device showed panchromatic spectral features in the IPCE action spectrum in the region 400-700 nm attaining efficiencies of 75-80percent; the spectrum is extended to the near-IR region attaining 40-45percent in 700-800 nm region, giving JSC/mA cm-2 = 19.28, VOC/mV = 753, FF = 0.719, and η = 10.4percent under standard AM 1.5 G one-sun irradiation. This performance is superior to what is obtained from the individual single-dye devices and the two-dye co-sensitized systems. The shifts of TiO2 potential upon dye uptake and the kinetics of charge recombination were examined through measurements of the charge extraction (CE) and intensity-modulated photovoltage spectroscopy (IMVS), respectively. Five co-sensitized systems were investigated to demonstrate that suppression of dye aggregation of YDD6 in the co-sensitized film is a key factor to further improve the device performance. © The Royal Society of Chemistry 2013.
Compendex Free Language: Action spectra; Charge extraction; Charge recombinations; Co-sensitization; Device performance; Dye aggregation; Dye uptake; Dye-sensitized solar cells; Intensity-modulated photovoltage spectroscopies; Key factors; Light-harvesting; Molar ratio; Molecular engineering; Near-IR; Organic dye; Photovoltaic performance; Porphyrin dimers; Semiconductor films; Spectral feature; TiO; Visible spectral regions
Compendex Descriptor: Cobalt; Porphyrins; Titanium dioxide
Compendex Mainhead: Solar cells
Reaxys Terms: Porphyrin - absorption spectrum; irradiation; kinetic type; photovoltaic effect; semiconductor