Organic Photovoltaics for Indoor Energy Harvesting: Recent Advances, Challenges, and Prospects

As high-efficiency energy conversion systems, indoor organic photovoltaic (IOPV) devices exhibit exceptional suitability for powering Internet of Things (IoTs)-integrated indoor electronics, such as environmental sensors, wearable technologies, and smart home systems under ambient illumination. Advancements in materials science and device engineering have driven substantial progress in optimizing the light-harvesting capabilities, power conversion efficiencies (PCEs), and operational stability of IOPV devices in recent years. This review systematically analyzes the spectral characteristics of indoor light sources, strategies for device architecture, and photovoltaic material design tailored for low-intensity indoor environments. Furthermore, it explores emerging applications of IOPV devices in human-device interaction paradigms, focusing on two critical dimensions: user-centric ocular safety protocols and light-induced emotional regulation mechanisms. This work synthesizes current advancements in performance optimization and innovative developments, providing critical insights to enhance the efficiency and practical deployment of IOPV technologies.