Highly Efficient Thermoelectric Microgenerators Using Nearly Room Temperature Pulsed Laser Deposition.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Thermoelectric materials convert heat energy into electrical energy.
• Bismuth telluride (Bi2Te3) and antimony telluride (Sb2Te3) are key thermoelectric materials.
• Efficient fabrication of high-performance thermoelectric thin films is crucial for energy harvesting.

Purpose of the Study:

• To demonstrate controlled deposition of Bi2Te3/Sb2Te3 thermoelectric thin films using pulsed laser deposition (PLD).
• To optimize growth conditions for achieving high thermoelectric power factor without post-treatment.
• To fabricate and characterize microgenerators based on these thermoelectric films.

Main Methods:

• Pulsed laser deposition (PLD) technique was employed to deposit Bi2Te3 and Sb2Te3 thin films on glass substrates using a shadow mask.
• Growth temperature was optimized to 45 °C to achieve desired stoichiometric composition and properties.
• Thermoelectric properties (Seebeck coefficient) and device performance (voltage, power density) were measured.

Main Results:

• Crystalline Bi2Te3 and Sb2Te3 films with high Seebeck coefficients (-78 μV K⁻¹ and 624 μV K⁻¹, respectively) were obtained.
• Films were deposited at a low temperature (45 °C) without post-annealing or added gases.
• Fabricated microgenerators demonstrated a maximum voltage of 50 mV and power density of 120 μW cm⁻² at a 30 K temperature difference.

Conclusions:

• Low-temperature PLD is an effective method for fabricating high-performance thermoelectric Bi2Te3/Sb2Te3 thin films.
• The developed thin films are suitable for creating efficient and compact microgenerators for low-temperature energy harvesting.
• This work represents a significant advancement towards practical thermoelectric energy harvesting devices.