Circumventing UV Light Induced Nanomorphology Disorder to Achieve Long Lifetime PTB7‐Th:PCBM Based Solar Cells |
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| Authors: | Quan Liu Johann Toudert Feng Liu Paola Mantilla‐Perez Miguel Montes Bajo Thomas P. Russell Jordi Martorell |
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| Affiliation: | 1. ICFO‐Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain;2. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA;3. Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, P. R. China;4. Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA, USA;5. Departament de Física, Universitat Politècnica de Catalunya, Terrassa, Spain |
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| Abstract: | Large area flexible electronics rely on organic or hybrid materials prone to degradation limiting the device lifetime. For many years, photo‐oxidation has been thought to be one of the major degradation pathways. However, intense illumination may lead to a burn‐in or a rapid decrease in performance for devices completely isolated from corrosive elements as oxygen or moisture. The experimental studies which are presented in here indicate that a plausible triggering for the burn‐in is a spin flip after a UV photon absorption leading to the accumulation of electrostatic potential energy that initiates a rapid destruction of the nanomorpholgy in the fullerene phase of a polymer cell. To circumvent this and achieve highly stable and efficient devices, a robust nanocrystalline ordering is induced in the PCBM phase prior to UV illumination. In that event, PTB7‐Th:PC71BM cells are shown to exhibit T80 lifetimes larger than 1.6 years under a continuous UV‐filtered 1‐sun illumination, equivalent to 7 years for sunlight harvesting at optimal orientation and 10 years for vertical applications. |
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| Keywords: | burn‐in organic photovoltaics PCBM photostability PTB7‐Th |
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