Metallic Conductivity of Ti 3 C 2 T x MXene Confirmed by Temperature-Dependent Electrical Measurements
Metallic Conductivity of Ti 3 C 2 T x MXene Confirmed by Temperature-Dependent Electrical Measurements
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通过与温度相关的电气测量证实 Ti 3 C 2 T x MXene 的金属电导率
DOI：
10.1021/acsmaterialslett.3c01234
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发表时间：
2024
影响因子：
11.4
通讯作者：
Sinitskii, Alexander
中科院分区：
文献类型：
--
作者：
Lipatov, Alexey;Bagheri, Saman;Sinitskii, Alexander
Ti3C2TX 是迄今为止最流行的 MXene，基于大量的理论预测和实验研究结果，它被广泛认为是一种金属材料。然而，尽管对 Ti3C2TX 的金属性质达成了普遍共识，但尚未有关于其与温度相关的电阻率 (ρ) 测量的报告，该测量可以证明在较宽的温度范围内 dρ/dT> 0 时电阻率随温度的预期增加。相反，迄今为止报道的所有 ρ(T) 数据（主要是在渗滤 Ti3C2Tx 薄片的宏观薄膜上收集的）都证明了与最小值的相关性，在不同的测量中在 90 至 250 K 的范围内观察到了最小值。在这项研究中，我们基于单独的高质量 Ti3C2Tx 薄片制造了电子器件，并进行了其随温度变化的电阻率测量。研究发现薄片的电阻率在 10-300 K 范围内随着温度的增加而增加，并且由此产生的 ρ(T) 依赖性可以通过金属电阻率温度依赖性的 Bloch-Grüneisen 模型准确描述，证实了 Ti3C2TX 的金属性质。我们还证明，Ti3C2Tx 单层的氧化会将单调递增的 ρ(T) 曲线转化为具有最小值的依赖性，这看起来与之前报道的渗透 MXene 薄膜的结果类似。具有类似半导体 dρ/dT < 0 行为的新兴低温尾部可以通过部分氧化的 MXene 中由于无序程度增加而产生的更强的电子散射来解释，并且可以使用马蒂森规则精确拟合所得的 ρ(T) 曲线，该规则结合了所有类型的散射体对金属传输特性的影响。这些实验验证了 Ti3C2Tx (dρ/dT> 0) 的金属性质，并为 dρ/dT< 0 低温尾部的出现提供了见解。我们还证明，多层 Ti3C2Tx 薄片即使在空气中退火后仍保留其纯金属 dρ/dT> 0 行为，这表明多层薄片的外层有效地保护了芯材 氧化层。这一结果表明，某些应用可能会受益于多层薄片的使用，因为它们改善了环境稳定性。
Ti3C2Tx, the most popular MXene to date, is widely regarded as a metallic material, based on numerous theoretical predictions and the results of experimental studies. Yet, despite this general consensus on the metallic nature of Ti3C2Tx, there have not been reports on its temperature-dependent resistivity (ρ) measurements that would demonstrate the expected increase of resistivity with temperature with dρ/dT> 0 in a wide temperature range. Instead, all ρ(T) data reported so far, which were mostly collected on macroscopic films of percolating Ti3C2Txflakes, demonstrate dependences with minima, which were observed in the range from 90 to 250 K in different measurements. In this study, we fabricated electronic devices based on individual high-quality Ti3C2Txflakes and performed their temperature-dependent resistivity measurements. The resistivity of flakes was found to increase with temperature in the 10–300 K range, and the resulting ρ(T) dependences can be accurately described by the Bloch–Grüneisen model for the temperature dependence of the resistivity of metals, confirming the metallic nature of Ti3C2Tx. We also demonstrate that an oxidation of a Ti3C2Txmonolayertransforms a monotonically increasing ρ(T) curve into a dependence with a minimum that looks similar to the previously reported results for percolating MXene films. The emerging low-temperature tail with a semiconductor-like dρ/dT< 0 behavior can be explained by the stronger electron scattering in a partially oxidized MXene due to an increased level of disorder, and the resulting ρ(T) curves can be accurately fitted using Matthiessen’s rule, which incorporates the effect of all types of scatterers on the transport properties of metals. These experiments verify the metallic nature of Ti3C2Tx(dρ/dT> 0) and provide insights into the origin of the emergence of a low-temperature tail with dρ/dT< 0. We also demonstrate thatmultilayerTi3C2Txflakes retain their purely metallic dρ/dT> 0 behavior even after annealing in air, suggesting that the outer layers of multilayer flakes effectively protect the core layers from oxidation. This result suggests that certain applications may benefit from the use of multilayer flakes because of their improved environmental stability.