Structural divergence of molecular hole selective materials for viable p-i-n perovskite photovoltaics: a comprehensive review

Abstract

Perovskite solar cells (PSCs) have garnered significant attention within the photovoltaic research community due to their remarkable progress in just one decade. Among the device configurations, the p-i-n structured PSC offers several advantages, including minimal hysteresis behavior, efficient hole extraction despite thin hole selective layers, and compatibility with flexible panels, with PCE values reaching over 25%. The interfacial contact between the charge-transporting and perovskite layers significantly enhances device efficiency by facilitating charge collection and improving device stability. This review aims to comprehend the influence of organic molecular hole-selective materials on the photovoltaic performance and stability of p-i-n PSC devices. Specifically, we explore the structural divergence of organic materials by categorizing them based on various central core units linked to the typical phenylamine donor. Additionally, we systematically analyze the intriguing role of a new class of self-assembled monolayers, classifying them as non-conjugated and conjugated anchoring materials. Furthermore, we provide an overview of the challenges of the current state of photovoltaic parameters and stability performance for these structural classifications. This summary offers valuable insights into developing novel hole-selective materials, enabling the realization of highly efficient and stable p-i-n PSC modules for commercial applications.