Discrepancy of Optimum Ratio in Bulk Heterojunction Photovoltaic Devices: Initial Cell Efficiency vs Long-Term Stability

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• 作者：Hyunmin Park ; Keel Yong Lee ; Wanjung Kim ; Hee-Won Shin ; Dong Hwan Wang ; Tae Kyu Ahn ; Jong Hyeok Park
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2013
• 出版时间：March 13, 2013
• 年：2013
• 卷：5
• 期：5
• 页码：1612-1618
• 全文大小：500K
• 年卷期：v.5,no.5(March 13, 2013)
• ISSN：1944-8252

文摘

Organic photovoltaic devices are difficult to commercialize because of their vulnerability to chemical degradation related with oxygen and water and to physical degradation with aging at high temperatures. We investigated the photophysical degradation behaviors of a series of poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl C61-butyric acid methyl ester (PC₆₀BM) bulk heterojunctions (BHJs) as a model system according to the donor鈥揳cceptor ratio. We found that the optimum P3HT:PC₆₀BM ratio in terms of long-term stability differs from that in terms of initial cell efficiency. On the basis of cell performance decays and time-resolved photoluminescence measurements, we investigated the effects of oxygen and material self-aggregation on the stability of an organic photovoltaic device. We also observed the changes in morphological geometry and analyzed the surface elements to verify the mechanisms of degradation.

Keywords:

organic solar cells; degradation; stability; bulk heterojunction; morphology; lifetime