Publication date: 1st July 2014
Solution-Processed organic-inorganic lead halide based perovskite solar cells have achieved tremendous progresses in the last few years, and power conversion efficiency (PCE) of more than 16% has been reported in the literature, showing great application aspect in the next future. [1-3] Stability of this type solar cell was then considered as the next key issue that needs to be solved before the industrialization. In this presentation, we will report our latest results on the degradation behaviors of planar heterojunction perovskite solar cells with a structure of ITO/PEDOT:PSS/CH3NH3PbIxCl3-x/PC61BM/Al. The solar cells were continuously illuminated with a white light, and the device performance was checked periodically with a special set-up that can automatically attach an external load to the circuit as required after I-V sweeping. Results indicate that degradation process of perovskite solar cells is highly depended on the attached external loads. When the solar cell was illuminated at open circuit, Voc increases slightly with the increase of testing time, whereas Jsc and FF decline under the continuous illumination, yielding a total decay of PCE. Such a decay process was slowed down when an external load was attached, and the decay rate was found to be negatively correlated to the external load. A detail discussion on the relationship between the degradation process and the external load, and a general decay mechanism will be given in this presentation.
[1] Snaith H J, "Perovskites: The Emergence of a New Era for Low-Cost, High-Efficiency Solar Cells" J. Phys. Chem. Lett. 2013, 4 (21), 3623-3630.
[2] Park N-G, "Organometal Perovskite Light Absorbers Toward a 20% Efficiency Low-Cost Solid-State Mesoscopic Solar Cell" J. Phys. Chem. Lett. 2013, 4 2423-2429.
[3] Jeon N J, Lee H G, Kim Y C, Seo J, Noh J H, Lee J,Seok S I, "o-Methoxy Substituents in Spiro-OMeTAD for Efficient Inorganic–Organic Hybrid Perovskite Solar Cells" J. Am. Chem. Soc. 2014, 136 (22), 7837-7840.