Ferroelectric Polarization and Oxygen Vacancy Synergistically Induced an Ultrasensitive and Fast Humidity Sensor for Multifunctional Applications

With the arrival of the Internet
of Things and artificial
intelligence,
humidity sensors monitoring water emissions from human metabolism
have attracted great attention in the fields of smart wearable devices
and noncontact human–machine interaction. However, their application
is seriously limited by the trade-off between the sensitivity and
response speed for traditional humidity sensors. Herein, to overcome
it, a self-powered high performance humidity sensor is developed on
the basis of the electric-poled and oxygen vacancy-rich BiFeO3 (BFO) ferroelectric material. The synergistic effect of ferroelectric
polarization and oxygen vacancy provides a strong driving force and
active adsorption sites for an abundance of OH/H2O adsorption,
resulting in an ultrahigh response (∼104) and ultrafast
response/recovery speed (∼84/376 ms). Benefiting from its promising
advantages, the wearable humidity sensor can accurately record the
respiration rate/depth and recognize different human respiratory behaviors
in real-time. Importantly, by utilizing the moisture from mouth-blowing
and skin, the sensors are successfully applied to noncontact control
of a robotic car, noncontact switch, and noncontact interface for
visualization applications. This work provides an effective strategy
for developing excellent humidity sensors that meet the requirement
of noncontact interaction for next-generation intelligent electronics.

随着物联网和人工智能技术的兴起，监测人体代谢水分排放的湿度传感器在智能可穿戴设备和非接触式人机交互领域备受关注。然而，传统湿度传感器的应用受到敏感性与响应速度之间的权衡所严重限制。为此，本研究基于电极化和富含氧空位的BiFeO3（BFO）铁电材料，开发了一种自供电高性能湿度传感器。铁电极化与氧空位的协同作用为大量的OH/H2O吸附提供了强大的驱动力和活性吸附位点，从而实现了超高的响应率（∼104）和超快的响应/恢复速度（∼84/376 ms）。得益于其卓越的潜力，该可穿戴湿度传感器能够精确记录呼吸速率/深度，并实时识别不同的人类呼吸行为。更重要的是，通过利用口吹和皮肤中的水分，这些传感器成功应用于非接触式机器人车的控制、非接触式开关以及非接触式可视化界面。本研究为开发满足下一代智能电子非接触式交互要求的优秀湿度传感器提供了一种有效的策略。