近期，本课题组张敏老师和黄有超同学以及刘德行同学分别以通讯作者和共同第一作者在材料领域国际知名期刊Advanced Functional Materials（SCI一区，2022年IF=19.924）上发表了题为“Flexible Liquid-Based Continuous Direct-Current Tribovoltaic Generators Enable Self-Powered Multi-Modal Sensing”的研究成果。
目前柔性可穿戴的应用场景迫切需要柔性直流发电机。传统的刚性接触分离型直流发电机通常具有不可忽视的摩擦损失，无法维持出色的输出，进而妨碍了其在连续运动场景中的实用性。本文报道了一种具有金属-液体-半导体堆叠结构的柔性直流摩擦伏特发电机。具有铂-水-铟镓氧化锌（IGZO）结构的发电机可提供高达2.3 μA cm-2的峰值短路电流密度、高达620 mV的峰值开路电压和高达0.1 μW cm-2的功率密度。结合密度泛函理论，在原子尺度上研究了不同固液界面间的接触特性，揭示了固液之间的电荷转移是影响器件输出的关键因素。固液界面处电荷转移诱导的界面电场和内建电场将共同作用于非平衡电子-空穴对的产生和分离，形成连续的直流电。本文提出的发电机即使在超过五万次振动循环或暴露于环境条件30天后仍能保持优异的性能，显示出非凡的稳定性。除了可以给电容器充电或驱动发光二极管外，该器件还被进一步证明可用于自供电多模传感，实现压力、位置姿势或温度的多功能检测。本文为设计下一代自供电可穿戴电子设备提供了潜在的解决方案和新的可能性。
Flexible tribovoltaic direct-current (DC) generators are urgently expected by wearable applications. Traditional rigid contact-separation type tribovoltaic DC generators normally have non-ignorable friction loss and cannot sustain outstanding outputs. This hinders their serviceability in continuous motion scenarios. Here, flexible liquid-based DC generators (FLGs) with metal-liquid-semiconductor indium gallium zinc oxide (IGZO) stack structures are reported. The FLG with Pt/H2O/IGZO structure delivers a peak short-circuit current density up to 2.3 µA cm−2, a peak open-circuit voltage up to 620 mV, and a power density up to 0.1 µW cm−2. The differences in the properties of different liquid–solid interfaces are studied by density functional theory, showing that the bond formation, charge-transfer-induced dipole electric field at the solid-liquid interface, and the built-in electric field are responsible for the generation and separation of electron-hole pairs to form continuous DC. The proposed FLG can keep excellent performance even after >5 × 104 shaking cycles or exposing to ambient conditions for 30 days, showing extraordinary stability. Besides charging capacitors or driving LEDs, the FLG is further demonstrated to work for self-powered multifunctional sensing, enabling pressure, position-posture, or temperature detections. This design offers potential solutions and novel possibilities for next-generation self-powered wearable electronics.
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