Large reverse saturable absorption under weak continuous incoherent light
Large reverse saturable absorption under weak continuous incoherent light
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DOI：
10.1038/nmat4081
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发表时间：
2014-10-01
期刊：
影响因子：
41.2
通讯作者：
Vacha, Martin
中科院分区：
文献类型：
--
作者：
Hirata, Shuzo;Totani, Kenro;Vacha, Martin
在显示出反饱和吸收（RSA）的材料中，光吸收随着入射到其上的光的功率增加而增加。迄今为止，RSA仅在使用非常强的光源（例如短脉冲激光）时才被观察到。在这里，我们表明，羟基甾体基质嵌入适当设计的芳香族分子作为受体和过渡金属配合物作为捐助者表现出高RSA暴露于弱非相干光在室温下，在空气中。通过光敏化的长寿命的室温三重态激子在受体中的积累具有大的三重态-三重态吸收系数，允许在低功率照射条件下吸光度的非线性增加。因此，连续暴露于弱光显著降低了用这些化合物制造的薄膜的透射率。这些光限幅特性可用于保护眼睛和光传感器免于暴露于由非相干源产生的强辐射，以及用于尚未用常规RSA材料实现的其它光吸收应用。
In materials showing reverse saturable absorption (RSA), the optical absorbance increases as the power of the light incident on them increases. To date, RSA has only been observed when very intense light sources, such as short-pulse lasers, are used. Here, we show that hydroxyl steroidal matrices embedding properly designed aromatic molecules as acceptors and transition-metal complexes as donors exhibit high RSA on exposure to weak incoherent light at room temperature and in air. Accumulation by photosensitization of long-lived room-temperature triplet excitons in acceptors with a large triplettriplet absorption coefficient allows a nonlinear increase in absorbance also under low-power irradiation conditions. As a consequence, continuous exposure to weak light significantly decreases the transmittance of thin films fabricated with these compounds. These optical limiting properties may be used to protect eyes and light sensors from exposure to intense radiation generated by incoherent sources and for other light-absorption applications that have not been realized with conventional RSA materials.