Tunability of the Band Energetics of Nanostructured SrTiO3 Electrodes for Dye-Sensitized Solar Cells

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• 作者：Shuming Yang ; Huizhi Kou ; Jichao Wang ; Hongbin Xue ; Huili Han
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：March 11, 2010
• 年：2010
• 卷：114
• 期：9
• 页码：4245-4249
• 全文大小：205K
• 年卷期：v.114,no.9(March 11, 2010)
• ISSN：1932-7455

文摘

The flat band edges (E_fb) of nanostructured SrTiO₃ electrodes have been determined in propionitrile (PN), acetylacetone (Acac), and PN/Acac with spectroelectrochemistry measurements. Specifically, a very negative E_fb was measured when only tetrabutylammonium perchloride (TBAP) was used as supporting electrolyte, while addition of Li⁺ ions shifts E_fb positively. The trap state distribution was investigated by the measurements of time-resolved current. The total trap state densities of 5.51 × 10¹⁶, 2.80 × 10¹⁶, and 1.83 × 10¹⁶ cm⁻² were determined in PN, PN/Acac, and Acac (all containing 0.2 mol·L⁻¹ TBAP), respectively, with trap distribution maximum located at −2.4, −1.6, and −1.5 V. The addition of Li⁺ also reduced the trap state densities, and the total trap state densities were calculated to be 4.19 × 10¹⁶, 2.38 × 10¹⁶, and 1.19 × 10¹⁶ cm⁻² in PN, PN/Acac, and Acac (all containing 0.2 mol·L⁻¹ TBAP and 0.5 mol·L⁻¹ LiClO₄), respectively. Finally the nanostructured SrTiO₃ electrode was sensitized with dye N3 and its photovoltage−photocurrent curves were measured in three electrolytes with PN, PN/Acac, and Acac as solvents, respectively. The N3-sensitized SrTiO₃ showed the highest open-circuit voltage (V_oc) and short-circuit current density (J_sc) in Acac, in good agreement with the electrochemical measurements that the nanostructured SrTiO₃ electrode has the flat band edge well matching with the excited state of N3 and the smallest trap state densities in Acac.