Active control of nanocrystal optical and electrical properties is crucial for many of their applications. By electrochemical (de)lithiation of Cu_2–xSe, a highly doped semiconductor, dynamic and reversible manipulation of its NIR plasmonics has been achieved. Spectroelectrochemistry results show that NIR plasmon red-shifted and reduced in intensity during lithiation, which can be reversed with perfect on–off switching over 100 cycles. Electrochemical impedance spectroscopy reveals that a Faradaic redox process during Cu_2–xSe (de)lithiation is responsible for the optical modulation, rather than simple capacitive charging. XPS analysis identifies a reversible change in the redox state of selenide anion but not copper cation, consistent with DFT calculations. Our findings open up new possibilities for dynamical manipulation of vacancy-induced surface plasmon resonances and have important implications for their use in NIR optical switching and functional circuits.

中文翻译：

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主动操纵NIR等离子体：通过电化学方法研究Cu _{2– x} Se

主动控制纳米晶体的光学和电学性质对其许多应用至关重要。通过对Cu _{2– x} Se进行电化学（去）锂化，可以实现高度掺杂的半导体，其NIR等离子体的动态和可逆操纵。光谱电化学结果表明，NIR等离子体激元在锂化过程中发生了红移并降低了强度，这可以通过100次循环的完美开关进行逆转。电化学阻抗谱显示，Cu _{2– x}期间的法拉第氧化还原过程Se（去）锂化负责光调制，而不是简单的电容充电。XPS分析可确定硒化阴离子的氧化还原状态可逆变化，但铜阳离子则不可逆，与DFT计算一致。我们的发现为空位诱导的表面等离振子共振的动态操纵开辟了新的可能性，并且对其在近红外光开关和功能电路中的应用具有重要意义。