Exploring Doping Mechanisms and Modulating Carrier Concentration in Copper Iodide: Applications in Thermoelectric...

Area of Science:

• Materials Science
• Solid-State Physics
• Nanotechnology

Background:

• Copper iodide (CuI) is a promising p-type semiconductor alternative to n-type metal oxides due to its flexibility and transparency.
• Effective doping methods for CuI are crucial for its application in advanced electronic and thermoelectric devices.
• Previous research demonstrated significant conductivity enhancement in sulfur-doped CuI (CuI:S) via liquid iodination.

Purpose of the Study:

• To investigate the doping mechanism of various sulfur (S) dopants in CuI.
• To develop a method for controlling electrical conductivity in CuI:S for thermoelectric applications.
• To systematically analyze the electrical and thermoelectric properties of CuI:S thin films.

Main Methods:

• Exploration of doping mechanisms using various S-dopants.
• Controlled adjustment of carrier concentration in CuI:S films.
• Accurate measurement of electrical conductivity, thermal conductivity, power factor, and thermoelectric figure of merit (ZT).
• Fabrication and testing of transparent and flexible thermoelectric power generators.

Main Results:

• Optimized CuI:S films achieved a maximum power factor of 5.76 µW cm⁻¹ K⁻² at a carrier concentration of 1.3 × 10²⁰ cm⁻³.
• A thermoelectric figure of merit (ZT) of 0.25 was recorded for the optimized CuI:S films.
• A flexible thermoelectric power generator demonstrated an output power density of 43 nW cm⁻² at a 30 K temperature difference.
• Mechanical durability tests confirmed the suitability of CuI:S for flexible applications.

Conclusions:

• Sulfur doping provides an effective route to control the electrical and thermoelectric properties of CuI.
• CuI:S thin films show significant potential for transparent and flexible thermoelectric power generation.
• The developed doping strategy enables tunable conductivity, crucial for optimizing thermoelectric performance.