Anion Effects in Organic Dye-Sensitized Mesoscopic Solar Cells with Ionic Liquid Electrolytes: Tetracyanoborate vs Dicyanamide

详细信息    查看全文

• 作者：Difei Zhou ; Yu Bai ; Jing Zhang ; Ning Cai ; Mei Su ; Yinghui Wang ; Min Zhang ; Peng Wang
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：January 27, 2011
• 年：2011
• 卷：115
• 期：3
• 页码：816-822
• 全文大小：280K
• 年卷期：v.115,no.3(January 27, 2011)
• ISSN：1932-7455

文摘

We compare the impacts of tetracyanoborate and dicyanamide anions in solvent-free ionic liquid electrolytes upon the optoelectronic features of dye-sensitized solar cells based on an organic push鈭抪ull chromophore. With respect to dicyanamide, tetracyanoborate confers a bathochromic and higher photocurrent response upon a dye-coated mesoporous titania film. Numerical simulations on electrical impedance spectroscopies disclose that tetracyanoborate anions evoke a downward displacement of the conduction-band edge of an electrolyte-sinking nanocrystalline film in comparison with dicyanamide, generating a more favorable energy-offset at the titania/dye interface and therefore a better exciton dissociation yield, as proved via the transient emission measurements. An effective recombination reaction rate constant U_0k is used to depict the charge-transfer behavior at the titania/electrolyte interface in dye-sensitized solar cells. The negative impact of an about 4 times larger U_0k of the dicyanamide cell is overwhelmed by the noticeably higher conduction band edge, leading to the experimentally observed anion-dependent open-circuit photovoltage.