Effect of structural compatibility of dye and hole transport material on performance of solid-state dye-sensitized solar cells

Solid-state dye-sensitized solar cells (ss-DSCs) are fabricated using Z907 or its thiophene derivative, CYC-B11, as a dye, and poly(3-hexylthiophene) (P3HT) or (2,2'.7.7'-tetrakis-(N,N-di-p-methoxyphenylamine) 9,9')-spirobifluorene (OMeTAD) as a hole transport material (HTM). The effect of the structural compatibility of dye molecules with HTM on device performance is investigated. The CYC-B11/P3HT device has a much higher short-circuit current density than Z907/P3HT and CYC-B11/OMeTAD devices. Results from the incident photo-to-electron conversion efficiency and impedance measurements support the use of P3HT, in place of OMeTAD, as HTM markedly increases the photocurrent throughout the absorption spectrum of CYC-B11 and significantly reduces the charge-transfer resistance at the TiO2/dye/HTM interface. As a result, the CYC-B11/P3HT ss-DSC that is fabricated from a thin (0.5 mu m) mesoporous TiO2 layer exhibits an outstanding power conversion efficiency of 3.66%. (C) 2012 Elsevier B.V. All rights reserved.