FTO-free and low-Pt-loading counter electrodes for dye-sensitized solar cells based on chemical bath deposited microstructured nickel layer

Abstract

Several hundred Ni microspheres with a diameter of 2–3 μm coated on frosted glass by chemical bath deposition are used as conductive substrates. Then, low-temperature immersion method (LTIM) and thermal decomposition method (TDM) are adopted respectively to deposit a thin Pt layer on Ni/glass and obtain Pt/Ni/glass electrodes which were employed as counter electrodes (CEs) for dye-sensitized solar cells (DSCs). The results show that the DSC device with well-optimized LTIM-electrode achieves a remarkable increase of 0.69 and 7.78% in fill factor (FF) and power conversion efficiency (PCE) respectively. However, well-optimized TDM-electrode and traditional sputtered-Pt-electrode demonstrate an efficiency of 6.59% and 7.55% with a FF of 0.65 and 0.69, respectively. In addition, the LTIM-electrode has the lowest Pt loading of only 15.4 μg/cm2 among these three types of CEs. Thus, LTIM presents here paved the way for the preparation of excellent electrocatalytic CEs with extremely low Pt loading on F-doped SnO2 (FTO) free of Ni/glass substrates in DSCs, greatly reducing the cost of present photovoltaic devices. Furthermore, this LTIM can be applied to deposit other noble metals on a variety of flexible substrates, including polyethylene naphthalate or terephthalate.