In this study, a new mechanism for doping of spiro-MeOTAD by Zn(TFSI)₂ is revealed, which is completely different from the mechanism induced by LiTFSI. The oxidation of spiro-MeOTAD is facilitated by complexation between the zinc cation and tert-butylpyridine (tBP) even in the absence of oxygen and light. The lone electron pair of nitrogen in tBP coordinates to the zinc cation, confirmed by the Fourier transform infrared spectroscopy peak at 1637 cm^–1 corresponding to a pyridine ring mode coupled with nitrogen coordinating to zinc as the Lewis site. The doping mechanism is also evidenced by computational calculations. The coordination of zinc to tBP and TFSI^– provides a driving force and stabilizes the oxidized spiro-MeOTAD species, showing the most favorable reaction by forming a [Zn(tBP)₃]⁺(TFSI^–) complex with a ΔE of −1.52 eV. Our discovery of the mechanism of doping by Zn(TFSI)₂ provides practical insight for the oxidation of spiro-MeOTAD by avoiding ambiguous aging processes in ambient or dry air at the risk of decomposition of other components.

中文翻译：

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在没有氧气和光照的情况下揭示锌络合掺杂螺-MeOTAD的机理

在这项研究中，揭示了一种新的Zn（TFSI）₂掺杂螺-MeOTAD的机制，这与LiTFSI诱导的机制完全不同。即使在没有氧气和光照的情况下，锌阳离子和叔丁基吡啶（t BP）之间的络合也会促进螺-MeOTAD的氧化。t BP中氮的孤电子对与锌阳离子配位，这是通过1637 cm ^–1处的傅立叶变换红外光谱峰确认的，该峰对应于吡啶环模式，再加上与锌配位的氮作为Lewis位点。掺杂机理也通过计算计算得到证明。锌的配合t BP和TFSI ^–提供驱动力并稳定氧化的螺-MeOTAD物质，通过形成具有ΔE为-1.52 eV的[Zn（t BP）₃ ] ⁺（TFSI ^–）配合物显示出最有利的反应。我们对Zn（TFSI）₂掺杂机理的发现通过避免环境或干燥空气中模棱两可的老化过程而冒着其他成分分解的风险，为螺-MeOTAD的氧化提供了实用的见识。