Dopant-Tunable Ultrathin Transparent Conductive Oxides for Efficient Energy Conversion Devices

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Ultrathin transparent conductive oxides (TCOs) are crucial for energy conversion devices but face limitations in reduced thickness and transparency trade-offs.
• Indium tin oxide (ITO) doping improves conductivity but often sacrifices transparency.

Purpose of the Study:

• To develop ultrathin TCOs with tunable work functions (WF) without compromising electrical and optical properties.
• To overcome the inherent trade-off between conductivity and transparency in conventional TCOs.

Main Methods:

• Fabrication of ultrathin (≤50 nm) TCOs using electric field-driven metal implantation (m-TCOs) with Ni, Ag, and Cu.
• Characterization of work function tunability, transmittance, and sheet resistance.
• Experimental and theoretical analysis of interstitial metal atom effects on WF and optical transparency.

Main Results:

• Achieved broad WF variation (0.97 eV) in m-TCOs.
• Maintained high UV-visible transmittance (89-93% at 365 nm) and low sheet resistance (30-60 Ω cm⁻²).
• Demonstrated universal applicability in organic light-emitting diodes (OLEDs), inorganic UV LEDs, and organic photovoltaics, with Ni-ITO enabling OLEDs without a hole injection layer.

Conclusions:

• Metal-doped TCOs (m-TCOs) enable effective carrier transport and light extraction beyond traditional TCO limits.
• The proposed m-TCOs offer a versatile solution for advanced energy conversion and optoelectronic devices.