光电耦合离子反俘获实现电致变色氧化物与器件性能恢复的研究

电致变色技术因能够动态调节光与热，在节能、显示等领域有很大的应用前景。提高电致变色材料与器件的稳定性与可逆性一直以来是电致变色领域的研究重点。电致变色非晶氧化物在长期循环过程中发生的离子俘获是造成其性能衰减的重要原因之一。尽管已报道的恒电流、恒电压方法可以通过离子反俘获多次有效地使电致变色非晶氧化物性能恢复，但都需长时间的高电压作用，而这会导致有机电解质分解以及多层电致变色器件中其它膜层的损坏。为了解决上述问题，本论文发展了一种全新的离子反俘获方法—光电耦合法，即施加恒压过程中辅以紫外光照射，或电化学循环过程中直接进行紫外光照射。论文具体研究内容与成果如下：

首先，以非晶WO₃为主要研究对象，系统地探究了光电耦合实现离子反俘获的条件、形式和影响因素。结果表明紫外光与恒压共同作用可以在降低恒压大小的前提下使WO₃性能恢复，但紫外光波长与功率、恒压大小以及光电耦合作用时间都会影响其离子反俘获效果。此外，在WO₃循环过程中直接进行紫外光照也能实现离子反俘获，使WO₃性能得到动态恢复。

其次，利用多种表征手段并结合电流密度曲线分析，揭示了光电耦合对非晶WO₃的离子反俘获机理。研究表明光电耦合能够有效分解浅层陷阱离子俘获生成的正交相Li₂WO₄晶粒以及深层陷阱离子俘获生成的W⁴⁺-Li₂WO₄耦合物、非晶Li₂WO₄和W⁴⁺-Li₂O耦合物，成功释放被浅层陷阱和深层陷阱俘获的Li离子，从而恢复WO₃薄膜性能。并且WO₃在光电耦合过程中的电流密度曲线前段出现的波谷可被视为离子反俘获的重要特征。

最后，通过将光电耦合离子反俘获法扩展到电致变色器件和其他阴极电致变色非晶氧化物中，结果表明光电耦合离子反俘获具有普适性。但由于不同非晶金属氧化物及其器件在循环过程中展现出不同的离子俘获特点，因此需要不同的紫外光与恒压共同组合才能达到最优的离子反俘获效果。

本论文的研究工作证实了光电耦合离子反俘获的可行性与普适性，为提高电致变色氧化物及器件循环寿命做出了有益的探索，同时也为电致变色非晶氧化物中离子俘获和反俘获的机理研究提供了新的思路。

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