Advancements and challenges of self-assembled monolayers as buried interfaces in inverted perovskite solar cells: from molecular design to automation-enabled data-driven optimization

Abstract

Inverted perovskite solar cells have achieved substantial efficiency gains through the introduction of self-assembled monolayers (SAMs) as hole-selective contacts. However, long-term operational stability requires the buried SAMs interface to remain dense, intact, and controllable throughout fabrication and device operation. This review focuses on SAMs-enabled buried interfaces in inverted device architectures. First, device architectures and the dominant loss and degradation pathways associated with buried contacts are summarized. Key mechanisms of SAMs are then discussed, including work-function tuning, improved energy-level alignment, defect passivation, and enhanced selective charge extraction. Subsequently, representative strategies for improving assembly quality and structural retention are highlighted, including co-adsorption, linker engineering, bilayer designs, and networked interfacial architectures, together with their impacts on coverage uniformity, interfacial coupling, and stress tolerance. From a methodological perspective, the machine-learning (ML) workflow applicable for this field is consolidated, covering data sources and governance, molecular, interfacial, process representations and modeling, as well as the multi-objective optimization coupled with closed-loop validation. We further integrate recent advances into four directions, namely, molecular design, cooperative assembly, manufacturability, and automation-enabled data-driven closed-loop workflows. Key limitations are also examined, including the effects of hidden variables, challenges in cross-source generalization, reproducibility issues, and variability in lifetime assessment. Finally, future priorities are outlined, emphasizing alignment with scalable manufacturing, tandem integration, reliability frameworks, and systematic data-driven decision making.