Photo-initiated, oxygen-mediated degradation of the molecules in the active layer of organic photovoltaic, OPV, devices currently limits advances in the development of solar cells. To address this problem systematically and at a molecular level, it is informative to quantify the kinetics of the pertinent processes, both in solution phase and in solid films. To this end, we examined the oxygen-dependent photophysics and photochemistry of selected functionalized fullerenes, thiophene derivatives, and a subphthalocyanine commonly used in OPV devices. We find that the photosensitized production of singlet molecular oxygen, O2(a1Δg), by these molecules is a key step in the degradation process. We demonstrate that the addition of either β-carotene or astaxanthin as antioxidants can inhibit degradation by a combination of three processes: (a) deactivation of O2(a1Δg) to the oxygen ground state, O2(X3Σg -), (b) quenching of the O2(a1Δg) precursor, and (c) sacrificial reactions of the carotenoid with free radicals formed in the photo-initiated reactions. For OPV systems in which reaction with O2(a1Δg) contributes to the degradation, the first two of these processes are desired and should have appreciable impact in prolonging the longevity of OPV devices because they do not result in a chemical change of the system.

中文翻译：

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用于有机光伏的原型化合物的氧依赖性光物理和光化学：在分子水平上抑制单线态氧引发的降解。

目前，光致化，氧介导的有机光伏OPV器件有源层中分子的降解限制了太阳能电池开发的进展。为了系统地，从分子水平上解决这个问题，量化溶液相和固体膜中相关过程的动力学是有益的。为此，我们检查了OPV装置中常用的选定功能化的富勒烯，噻吩衍生物和亚酞菁的氧依赖性光物理性质和光化学性质。我们发现这些分子通过光敏化产生单线态分子氧O2（a1Δg）是降解过程中的关键步骤。我们证明，添加β-胡萝卜素或虾青素作为抗氧化剂可以通过以下三个过程的组合来抑制降解：（a）将O2（a1Δg）减活至氧基态，O2（X3Σg-），（b）O2（a1Δg）前体淬灭，以及（c）类胡萝卜素与光致自由基形成的牺牲反应-引发的反应。对于其中与O2（a1Δg）的反应会导致降解的OPV系统，需要这两个过程中的前两个过程，并且由于它们不会导致系统的化学变化，因此在延长OPV装置的使用寿命方面应具有可观的影响。