3D Printed Iron Pyrite via Meniscus Confinement: A Promising Material for Photovoltaic Solar Cells

The meniscus-confined electrochemical 3D printing (MC-E3DP) process has emerged as a novel approach for fabricating sub-micron complex structures through localized electrochemical deposition from salt solutions of desired materials. This study reports, for the first time, the MC-E3DP fabrication of iron oxide (Fe₃O₄) thin films on indium tin oxide (ITO)-coated glass substrates. The Fe₃O₄ films are characterized using XRD, Raman spectroscopy, and UV-vis pectroscopy, confirming phase purity. Subsequently, the Fe₃O₄ thin films are subjected to sulfurization under varying conditions to synthesize iron pyrite (FeS₂) thin films, a promising solar absorber material for photovoltaic applications. The sulfurized FeS₂ thin films are analyzed for phase purity using XRD, XPS, and Raman spectroscopy, while FESEM was employed to study their morphology. UV-vis-NIR spectroscopy reveals high absorption coefficients (∼10⁵ cm^-1 for wavelengths below 700 nm) and indirect bandgaps ranging from 0.78 to 0.86 eV. All films exhibited n-type conductivity with a charge carrier density of ∼10¹⁹ cm^-3. Photoelectrochemical studies demonstrated a stable photocurrent response, indicating their suitability for solar cell applications. The MC-E3DP process offers exceptional control over structure and growth, making it a promising technique for creating device architectures tailored for specific applications.