Enhanced Lifetime of Cyanine Salts in Dilute Matrix Luminescent Solar Concentrators via Counterion Tuning
Enhanced Lifetime of Cyanine Salts in Dilute Matrix Luminescent Solar Concentrators via Counterion Tuning
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DOI：
10.1021/acsphotonics.3c00602
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发表时间：
2023-08-23
期刊：
影响因子：
7
通讯作者：
Lunt，Richard R.
中科院分区：
文献类型：
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作者：
Herrera，Christopher K.;Vahdani，Aria;Lunt，Richard R.
有机发光体具有光谱性质可调、发光强、溶解度高、波长选择性好等特点，在能量采集和发光方面具有巨大的潜力。为了充分发挥它们的潜力，发光体的寿命必须在光照下延长到很多年。然而，许多有机发光体具有降解和快速光漂白的趋势，导致人们对有机分子固有的不稳定性的看法。在这项工作中，我们证明了通过交换七甲基菁盐的反离子，稀释的菁盐的光稳定性和相应的寿命可以在光照下从10h提高到超过65000h的数量级。为了帮助关联和理解这一现象背后的潜在机制，测量和计算了每一对的水接触角和结合能。我们发现，水接触角的增加，因此疏水性的增加，通常与寿命的延长有关。同样，阳离子和阴离子之间的绝对结合能越低，寿命越长。利用结合能理论，我们预测了一种新阴离子的稳定性，并用实验进行了验证，得到了良好的一致性。展望未来，这些因素可用于快速筛选和识别用于一系列能量收集和发光应用的高度光稳定的有机发光体盐体系。
Organic luminophores offer great potential for energy harvesting and light emission due to tunable spectral properties, strong luminescence, high solubility, and excellent wavelength selectivity. To realize their full potential, the lifetimes of luminophores must extend to many years under illumination. Many organic luminophores, however, have a tendency to degrade and undergo rapid photobleaching, leading to the perception of intrinsic instability of organic molecules. In this work, we demonstrate that by exchanging the counterion of a heptamethine cyanine salt the photostability and corresponding lifetime of dilute cyanine salts can be enhanced by orders of magnitude from 10 h to an extrapolated lifetime of greater than 65,000 h under illumination. To help correlate and comprehend the underlying mechanism behind this phenomenon, the water contact angle and binding energy of each pairing were measured and calculated. We find that increased water contact angle, and therefore increasing hydrophobicity, generally correlates to improved lifetimes. Similarly, a lower absolute binding energy between cation and anion correlates to increased lifetimes. Utilizing the binding energy formalism, we predict the stability of a new anion and experimentally verify it with good consistency. Moving forward, these factors could be used to rapidly screen and identify highly photostable organic luminophore salt systems for a range of energy harvesting and light-emitting applications.