TAGRA 2025

This work presents a comprehensive overview of the development of ETL-free perovskite solar cells, highlighting their progress, current challenges, and prospects. By eliminating the electron transport layer (ETL), these devices simplify the solar cell architecture, reducing fabrication complexity and cost while maintaining competitive performance. The discussion begins with the fundamental principles and material innovations that have enabled ETL-free designs, including advances in perovskite composition, interface engineering, and device stability. Key obstacles such as charge extraction efficiency, interfacial recombination, and long-term operational stability are examined in detail. Various fabrication strategies, including surface passivation and multifunctional buffer layers, are compared for their effectiveness in addressing these issues. Looking ahead, the focus turns to scalable manufacturing approaches, improved reliability under real-world conditions, and exploration of novel perovskite compositions to enhance performance and commercial viability. Overall, the work aims to guide researchers toward simpler, more efficient, and cost-effective perovskite solar cells based on ETL-free architectures.