RESUMO
Wearable electronic devices have great potential in the fields of the Internet of Things (IoT), sports and entertainment, and healthcare, and they are essential in advancing the development of next-generation electronic information technology. However, conventional lithium batteries, which are currently the main power supply of wearable electronic devices, have some critical issues, such as frequent charging, environmental pollution, and no surface adaptability, which limit the further development of wearable electronic devices. To address these challenges, we present a flexible hybrid photothermoelectric generator (PTEG) with a simple structure composed of a thermoelectric generator (TEG) and a light-to-thermal conversion layer to simultaneously harvest thermal and radiation energies based on a single working mechanism. The mature mass-fabrication technology of screen printing was applied to successively prepare n-type (i.e., Bi2Te2.7Se0.3) and p-type (i.e., Sb2Te3) thermoelectric inks atop a polyimide substrate to form the TEG with a serpentine thermocouple chain, which was further covered by a light-to-thermal conversion layer to constitute the PTEG. The resulting PTEG with five pairs of thermocouples generated a direct-current output of 82.4 mV at a temperature difference of 50 °C and a direct-current output of 41.2 mV under 20 mW/cm2 infrared radiation. Meanwhile, the remarkable mechanical reliability and output stability were experimentally demonstrated through a systematic test, which indicated the feasibility and potential of the developed PTEG as a reliable power source. In addition, as desirable application prototypes, the fabricated PTEGs have been successfully demonstrated to harvest biothermal energy and infrared radiation to drive portable electronic devices (e.g., a calculator and a clock). Hybrid energy harvesting technology based on a simple structure may provide a new solution to current power supply issues of wearable electronic device.
RESUMO
This paper presents a novel approach of annular concentric split rings microelectromechanical resonators with tether configuration to reduce anchor loss and gives very high-quality factor (Q) 2.97 Million based on FEA (Finite Element Analysis) simulation. The operating frequencies of these resonators are 188.55 MHz to 188.62 MHz. When the proposed SR (square rectangle) hole shaped one dimensional phononic crystal (1D PnC), and two dimensional phononic crystal (2D PnC) structure consist of very wide and complete band gaps is applied to novel design rings MEMS resonators, the quality factor (Q) further improved to 19.7 Million and 1750 Million, respectively, by using the finite element method. It is also observed that band gaps become closer by reducing the value of filling fraction, and proposed SR PnC gives extensive peak attenuation. Moreover, harmonic response of ring resonator is verified by the perfect match layers (PML) technique surrounded by resonators with varying width 1.5λ, and 3λ effectively reduce the vibration displacement.