Enhancing thermoelectric performance in flexible fabric-based Mo-doped CuAl2O4: Insights into carrier type modification and electrical conductivity optimization

Abstract

In this work, we report the thermoelectric behaviour of flexible fabric-based Mo doped CuAl2O4. The doped Mo atom occupies the interstitial positions of the spinel lattice of CuAl2O4. This results the lattice expansion and also provides the carrier electrons. Initially, the pristine CuAl2O4 has the carrier concentration of 2.81 × 1014 cm−3, while doping with molybdenum, it not only increases the concentration of the carriers (about −7.65 × 1015 cm−3), but also changes the carrier type. The minimum doping (2 %) of molybdenum to spinel CuAl2O4 (CuAl2O4Mo0.02) creates the fermi level near to the conduction band, which reduces the band gap and results in the effective electrical conductivity as 0.69 Scm−1 at 340 K. The heavy doping enhances the scattering process. This leads to deduction of mobility and lower the electrical conductivity. The highest power factor of 0.0599 μWcm−1K−2 is achieved for the CuAl2O4Mo0.06 sample at 300 K. This is due to the high Seebeck coefficient value of the sample and has an ultralow thermal conductivity value of 0.056 W/mK. The highest output voltage of 3.9 mV is achieved for parallelly connected p-type CuAl2O4 -n-type CuAl2O4Mo0.02 thermoelectric device at the temperature difference of ΔT = 4.1 K. This research findings justify, the doping of molybdenum in the spinel lattice effectively enhances the thermoelectric properties of CuAl2O4 and provide the new ideas for the flexible, wearable fabric based thermoelectric research.