Lead-Free Inverted Perovskite Solar Cells using Cu₂O/ZnO Inorganic Transport Layers: Synthesis, Characterization and Device Performance

Abstract

Perovskite solar cells (PSCs), often referred to as fourth-generation solar cells, have attracted significant research interest in recent years due to their high-power conversion efficiency, simple fabrication processes, low processing temperatures, mechanical flexibility, lightweight nature, and the low cost of constituent materials compared with conventional silicon-based solar cells. However, the long-term stability and environmental concerns associated with PSCs remain major obstacles to their commercialization. The aim of this study focuses on the synthesis and characterization of solar cell materials, as well as the fabrication of an inverted perovskite solar cell device. In this work, lead-free perovskite solar cells employing inorganic charge transport materials were carefully designed and systematically investigated. This paper addresses an important and timely research challenge in the field of photovoltaic materials, particularly the development of environmentally friendly technology, lead-free perovskite solar cells. The incorporation of inorganic transport layers (Cu₂O and ZnO) in combination with a tin-based perovskite absorber within an inverted planar device architecture contributes to enhanced device stability and reduced material toxicity. This work is highly relevant to researchers with interest in sustainable energy materials and low-cost solar cell fabrication. Furthermore, the achieved power conversion efficiency of 7.44% and the retention of approximately 95% of the initial device performance after 1,000 hours of continuous operation under standard solar illumination (1,000 W m⁻²) in ambient conditions highlight the practical significance of this study.