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A flexible and ultralight planar thermoelectric generator based on 15 thermocouples composed of n-type bismuth telluride (Bi2Te3) and p-type antimony telluride (Sb2Te3) legs (each with 400 nm thick) connected in series, on 25 μm thick Kapton substrate, was fabricated with impressive power factor values of 2.7 and 0.8 mW K–2 m–1 (at 298 K) for Bi2Te3 and Sb2Te3 films, respectively. The p–n junction thermoelectric device can generate a maximum open-circuit voltage and output power of 210 mV and 0.7 μW (3.3 mW cm–2), respectively, for a temperature difference of 35 K, which is higher than the one observed for a conventional thermoelectric device with metallic contacts for p–n junctions. The results were combined with numerical simulations, showing a good match between the experimental and the numerical results. The current density versus voltage (J–V) characteristics of the fabricated p–n junctions revealed a diode behavior with a turn-on voltage of ≈0.3 V and an impressive rectifying ratio (I +1V/I –1V) of ≈2 × 104.

This paper presents a thermoelectric (TE) generator and a solid-state battery for powering microsystems. Prototypes of TE generators were fabricated and characterized. The TE generator is a planar microstructure based on thin films of n-type bismuth telluride (Bi 2 Te 3) and p-type antimony telluride (Sb 2 Te 3), which were deposited using co-evaporation. The measurements on selected samples of Bi 2 Te 3 and Sb 2 Te 3 thin films indicated a Seebeck coefficient in the range of 90-250 µV K −1 and an in-plane electrical resistivity in the range of 7-17 µ m. The measurements also showed TE figures-of-merit, ZT, at room temperatures (T = 300 K) of 0.97 and 0.56, for thin films of Bi 2 Te 3 and Sb 2 Te 3 , respectively (equivalent to a power factor, PF, of 4.87 mW K −2 m −1 and 2.81 mW K −2 m −1). The solid-state battery is based on thin films of: an anode of tin dioxide (SnO 2), an electrolyte of lithium phosphorus oxynitride (Li x PO y N z , known as LiPON) and a cathode of lithium cobaltate (LiCoO 2 , known as LiCO), which were deposited using the reactive RF (radio-frequency) sputtering. The deposition and characterization results of these thin-films layers are also reported in this paper.

We report fabrication of reduced graphene oxide (rGO) films using chemical reduction by hydrazine hydrate and rGO paper-like samples using low temperature treatment reduction. Structural analysis confirms the formation of the rGO structure for both samples. Current-voltage (I V) measurements of the rGO film reveal semiconductor behavior with the maximum current value of $3 Â 10 4 A. The current for the rGO paper sample is found to be, at least, one order of magnitude higher. Moreover, bipolar resistance switching, corresponding to memristive behavior of type II, is observed in the I V data of the rGO paper. Although precise values of the rGO film conductivity and the Seebeck coefficient could not be measured, rGO paper shows an electrical conductivity of 6.7 Â 10 2 S/m and Seebeck coefficient of À6 lV/ C. Thus, we demonstrate a simplified way for the fabrication of rGO paper that possesses better and easier measurable macroscopic electrical properties than that of rGO thin film. Published by AIP Publishing. [http://dx