Recent progress of indoor organic photovoltaics-From device performance to multifunctional applications

Owing to the prosperity of the internet of things (IoTs), indoor organic photovoltaic (IOPV) devices with substantial merits (e.g., light weight, portability, flexibility, semitransparency, operational stability) are emerging as reliable indoor photon harvesters to drive low-power electronic devices. In such cases, the effective utilization of indoor photons is significant, as indoor light intensity is much weaker than the standard 1-Sun illumination. Considerable efforts have been devoted to improving the power conversion efficiency (PCE) of indoor solar cells and modules in past few years. So far, the efficiency of indoor light harvesters has surpassed 30%, sufficient to power quite a few indoor off-grid electronic devices. Given that the expected efficiency optimization has already realized through various approaches, a critical review is significant for the appropriate applications of IOPV devices. Herein, we provide a detailed review of the basic knowledge of IOPV devices, current fabrication strategies, and further illustrate their multifunctional applications. Possible challenges and prospects of IOPV systems are presented elaborately for further developments and applications.