Enhanced thermoelectric performance of CdO : Ag nanocomposites

Abstract

CdO : Ag nanocomposites with metallic Ag nanoparticles embedded in the polycrystalline CdO matrix were synthesized by the solid-state reaction method. The addition of Ag led to increased grain boundaries of CdO and created numerous CdO/Ag interfaces. By incorporating Ag into the CdO matrix, the power factor was increased which was probably due to the carrier energy filtering effect induced by the enhanced energy-dependent scattering of electrons. In addition, reduced thermal conductivity was also achieved by stronger phonon scattering from grain boundaries, CdO/Ag interfaces and Ag nanoparticles. These concomitant effects resulted in enhanced ZT values for all CdO : Ag nanocomposites, demonstrating that the strategy of introducing metallic Ag nanoparticles into the CdO host was very effective in optimizing the thermoelectric performance.

Energy Filtering of Charge Carriers: Current Trends, Challenges, and Prospects for Thermoelectric Materials

“…An interesting case of EF in oxides is reported by Gao et al Metallic Ag particles randomly dispersed in a CdO matrix were found to yield simultaneous increase of both Seebeck coefficients and charge carrier concentration. EF at the CdO/Ag interfaces was proposed as a plausible explanation for this observation, which is made possible by the stability of Ag against the oxidizing atmosphere prevailing during air‐sintering of the CdO polycrystal.…”

“…It should be noted that the case of Ag is somewhat exceptional, and not many metallic systems would have been suitable for serving as particles in oxides due to stability problems. Such an energy dependent scattering is responsible for an unusual behavior of the EF effect . As opposed to the stability issues introduced by metallic inclusions in oxides, Ohtaki et al observed that nanovoids effectively tune the Seebeck coefficient in ZnO .…”

Recent Progress in Multiphase Thermoelectric Materials

“…Silver nanoparticles enhanced the Seebeck coefficient of CdO-Ag composites [85]-a potential barrier of E B = 0.1 eV between the work function of Ag and the electron affinity of CdO increased the resistivity from 1.5 mΩ cm to 1.7 mΩ cm for a sample with 0.03% of Ag and increased the Seebeck coefficient from −120 µV/K for the pristine sample to −129 µV/K for the sample with 0.03% of Ag at 800 K.…”

Support of Cd doping in SnO2 nanoparticles to enhance its thermoelectric parameters

“…Gao, Wang, Liu, Zhai, et al reported the effect of 0.01% Ni doped in CdO at 1000k, which revealed the best ZT = 0.43 value as compared to the other thermoelectric materials [14]. Gao, Wang, Liu, Zha, et al have seen a maximum increased ZT value, when Ag alloyed with CdO [15]. Park et al study showed an improved power factor of about 1.25*10 -3 Wm -1 K -2 at 1073K, when adding SnO in Zn of sample Zn o.99 Sn 0.01 O [16].…”