Oxide-Based Solar Cell: Impact of Layer Thicknesses on the Device Performance

Area of Science:

• Materials Science
• Renewable Energy
• Semiconductor Physics

Background:

• Zinc oxide (ZnO) and copper(I) oxide (Cu2O) are promising materials for thin-film solar cells.
• Combinatorial fabrication allows rapid screening of material parameters.
• Understanding layer thickness effects is crucial for optimizing heterojunction solar cell performance.

Purpose of the Study:

• To fabricate a library of ZnO/Cu2O heterojunction solar cells.
• To investigate the influence of ZnO and Cu2O layer thicknesses on photovoltaic performance.
• To determine the optimal thickness for maximizing solar cell efficiency.

Main Methods:

• Spray pyrolysis technique used for device fabrication on ITO-coated glass.
• Combinatorial approach varying ZnO (50-320 nm) and Cu2O (200-800 nm) layer thicknesses.
• Photovoltaic performance characterization, including short-circuit current density (Jsc).

Main Results:

• Photovoltaic performance strongly depends on absorber (Cu2O) layer thickness.
• Maximum Jsc of 3.9 mA/cm² achieved when Cu2O thickness exceeds ~700 nm.
• Reduced layer thicknesses significantly decrease device performance due to optical losses and recombination.

Conclusions:

• Optimal ZnO/Cu2O heterojunction solar cell performance requires specific, relatively thick absorber layers.
• Device efficiency is limited by interfacial phenomena and insufficient built-in bias formation in thinner layers.
• Spray pyrolysis is a viable method for fabricating combinatorial libraries of ZnO/Cu2O solar cells.