Landi Giovanni, Granata Veronica, Germano Roberto, Pagano Sergio, Barone Carlo
ENEA, Casaccia Research Center, Via Anguillarese 301, 00123 Rome, Italy.
Dipartimento di Fisica "E.R. Caianiello", Università degli Studi di Salerno, 84084 Fisciano, Italy.
Nanomaterials (Basel). 2022 Jun 29;12(13):2227. doi: 10.3390/nano12132227.
An environmentally-friendly temperature sensor has been fabricated by using a low-cost water-processable nanocomposite material based on gelatin and graphene. The temperature dependence of the electrochemical properties has been investigated by using cyclic voltammetry, chronopotentiometry and impedance spectroscopy measurements. The simple symmetric device, composed of a sandwich structure between two metal foils and a printable graphene-gelatin blend, exhibits a dependence on the open-circuit voltage in a range between 260 and 310 K. Additionally, at subzero temperature, the device is able to detect the ice/frost formation. The thermally-induced phenomena occur at the electrode/gel interface with a bias current of a few tens of μA. The occurrence of dissociation reactions within the sensor causes limiting-current phenomena in the gelatin electrolyte. A detailed model describing the charge carrier accumulation, the faradaic charge transfer and diffusion processes within the device under the current-controlled has been proposed. In order to increase the cycle stability of the temperature sensor and reduce its voltage drift and offset of the output electrical signal, a driving circuit has been designed. The eco-friendly sensor shows a temperature sensitivity of about -19 mV/K, long-term stability, fast response and low-power consumption in the range of microwatts suitable for environmental monitoring for indoor applications.
一种基于明胶和石墨烯的低成本可水加工纳米复合材料制造了一种环保型温度传感器。通过循环伏安法、计时电位法和阻抗谱测量研究了电化学性质的温度依赖性。由两个金属箔和可印刷的石墨烯 - 明胶混合物之间的三明治结构组成的简单对称器件，在260至310 K的范围内表现出对开路电压的依赖性。此外，在零下温度下，该器件能够检测冰/霜的形成。热诱导现象发生在电极/凝胶界面，偏置电流为几十μA。传感器内离解反应的发生导致明胶电解质中的限流现象。提出了一个详细的模型，描述了电流控制下器件内电荷载流子积累、法拉第电荷转移和扩散过程。为了提高温度传感器的循环稳定性并降低其电压漂移和输出电信号的偏移，设计了一个驱动电路。这种环保型传感器在适用于室内环境监测的微瓦范围内显示出约 -19 mV/K的温度灵敏度、长期稳定性、快速响应和低功耗。
