SYNTHESIS AND CHARACTERIZATION OF AG2SE NANOWIRES FOR FLEXIBLE THERMOELECTRIC MATERIALS

• Main Author: Shaf, Rachman
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86963
• Institution: Institut Teknologi Bandung

Flexible n-type thermoelectrics are a promising avenue in wearable thermoelectric technology. In this study, a flexible Ag?Se thermoelectric material with a ZT value of 0.3 at room temperature and a bending radius of 2.4 mm was successfully developed. The material was fabricated using a hot press method at 200°C and 28 MPa, employing Ag?Se nanowires (NWs) synthesized via a one-pot direct conversion reaction between selenium nanowires and Ag? ions. X-ray diffraction (XRD) analysis confirmed the orthorhombic crystal structure of the Ag?Se NWs, with lattice parameters of a = 4.332 Å, b = 7.063 Å, and c = 7.769 Å. Scanning electron microscopy (SEM) revealed nanowires with an average diameter of 88 nm and lengths exceeding 10 µm. The quality of the Ag?Se NWs was found to depend on the chemical reduction process used to produce selenium nanowires, synthesized from a Na?SeO? solution with glucose as a reducer. Raman spectroscopy and SEM imaging of the selenium nanowires indicated an average diameter of 83 nm, lengths over 10 µm, and characteristic vibration modes at 237 cm?¹ and 144 cm?¹. The ZT value was determined using electrical resistivity and Seebeck coefficient measurements from a Linseis LSR-3 system and heat diffusivity analysis with a NETZSCH-Geratebau laser flash analyzer. This work highlights that reducing porosity, which influences electrical conductivity, is a critical factor for further enhancing the ZT value. The findings demonstrate the potential of Ag?Se-based thermoelectrics for flexible and efficient energy harvesting applications.