石墨烯包裹的 V2O5 纳米粒子中小极化子跳跃到类似 Efros–Shklovskii 的可变范围跳跃跃迁：莫特间隙的作用,The Journal of Physical Chemistry C

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石墨烯包裹的 V2O5 纳米粒子中小极化子跳跃到类似 Efros–Shklovskii 的可变范围跳跃跃迁：莫特间隙的作用
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2022-12-29 , DOI: 10.1021/acs.jpcc.2c05863
D. Surya Bhaskaram _{1,

2} , G. Govindaraj ₁

Affiliation

V ₂ O ₅在各个领域都是很有前途的候选者，并已证明有利于极化子形成。极化子移动缓慢，质量额外，因此会影响电导率。电荷传输/电导率是决定设备效用的关键因素之一，并且由于极化子的缓慢运动而受到损害。为了解决这个问题，将石墨烯结合到V ₂ O ₅中被广泛实践。V ₂ O ₅表现出小的极化子跳跃是事实，并且在低温下在石墨烯中观察到高移动电子的可变范围跳跃。V ₂ O _{5中包含石墨烯}显示出导电性增强，因此已针对各种应用进行了广泛研究。电导率增强的原因被认为是石墨烯中存在离域电子，这使得样品富含电子并增加了电导率。但电导率增强的实际机制尚不清楚。这促使我们探索石墨烯包裹的 V ₂ O ₅的电气特性。令我们惊讶的是，石墨烯的加入完全改变了载流子的动力学。复合材料中的极化子在 143–263 K 的温度范围内选择可变范围跳跃超过 Arrhenius 型小极化子跳跃。V ₂ O ₅和还原氧化石墨烯 (RGO) 包裹的 V ₂ O的交流电导率 σ'(ω) 数据₅使用 Cole-Cole 型组合传导和介电模型进行分析。极化子的σ _dc显示出对 V ₂ O ₅的T ^–1依赖性和对 RGO 包裹的 V ₂ O ₅ (VRGO)的T ^{–1/2依赖性。}一般来说，在低温下 ( T < 100 K)，这种行为被解释为 Efros–Shklovskii (ES) VRH，但我们所涵盖的温度范围 (143–263 K) 不能证明 ES-VRH。使用 XRD 和温度相关拉曼等工具以及电导率测量对载流子环境进行详细概述，以说明T ^–1/2极化子的依赖性。各种测量结果指向 V ₂ O ₅中加入石墨烯后莫特间隙的起源，从而控制了极化子的惊人行为。

"点击查看英文标题和摘要"

Small Polaron Hopping to Efros–Shklovskii-Like Variable Range Hopping Transition in Graphene-Wrapped V2O5 Nanoparticles: The Roleplay of the Mott Gap

V₂O₅ is a promising candidate in varied fields and has proven to favor polaron formation. Polarons are slow-moving with extra mass, thus affecting conductivity. Charge transport/conductivity is one of the key factors deciding device utility and is compromised due to the slow motion of polarons. To solve this, incorporating graphene into V₂O₅ is widely practiced. V₂O₅ exhibiting small polaron hopping is a fact, and variable range hopping of highly mobile electrons is observed in graphene at low temperatures. The inclusion of graphene into V₂O₅ shows conductivity enhancement and hence has been widely studied for varied applications. The reason for conductivity enhancement is considered to be the presence of delocalized electrons in graphene, which makes the sample electron-rich and increases conductivity. But the actual mechanism of conductivity enhancement is unclear. This led us to explore the electrical properties of graphene-wrapped V₂O₅. To our surprise, the inclusion of graphene completely changes the dynamics of charge carriers. Polarons in composite chose variable range hopping over Arrhenius-type small polaron hopping in the temperature range of 143–263 K. ac conductivity σ′(ω) data of V₂O₅ and reduced graphene oxide (RGO)-wrapped V₂O₅ are analyzed using the Cole–Cole-type combined conduction and dielectric model. σ_dc of polarons shows T^–1 dependence for V₂O₅ and T^–1/2 dependence for RGO-wrapped V₂O₅ (VRGO). In general, at low temperatures (T < 100 K), such behavior is interpreted to be Efros–Shklovskii (ES) VRH, but the temperature range (143–263 K) that we have covered cannot justify ES-VRH. A detailed overview of the carrier environment is carried out using tools such as XRD and temperature-dependent Raman along with conductivity measurements to account for the T^–1/2 dependence of polarons. The results of various measurements point toward the origin of Mott gap in V₂O₅ after incorporating graphene into it, thus controlling the surprising behavior of polarons.

更新日期：2022-12-29

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