Application of Electrochemical Impedance Spectroscopy in Organic Solar Cells with Vertically Aligned TiO2 Nanorod Arrays as Buffer Layer
Single-crystal TiO2 nanorod film was synthesized directly on FTO substrates with various lengths by changing the hydrothermal growth parameters including growth time and growth temperature. The obtained nanorod arrays were incorporated in organic solar cells as buffer layer instead of PEDOT: PSS. Results showed that devices assembled with TiO2 nanorods film of 200 nm in length exhibited a lower open-circuit voltage but a significantly higher short-circuit current density compared to those of normal FTO/PEDOT: PSS/P3HT: PCBM/Al structure with a comparable active layer thickness. Overall the power conversion efficiency was boosted by two-fold. Electrochemical impedance spectroscopy (EIS) analyses revealed that the improvement in the photovoltaic performance was induced by the inhibited recombination and consequently enhanced electron lifetime.
Wei Pan and Jianghong Gong
Y. C. Zhang et al., "Application of Electrochemical Impedance Spectroscopy in Organic Solar Cells with Vertically Aligned TiO2 Nanorod Arrays as Buffer Layer", Key Engineering Materials, Vols. 512-515, pp. 1598-1603, 2012