Study of Photovoltaic Parameters of Efficient Bulk-Heterojunction Organic Solar Cells for Indoor Applications Under Varied Intensities and Indoor LED Lighting

Bulk-heterojunction devices with D18 and Y12 as active material were fabricated with an inverted ITO/zinc oxide/active material/molybdenum (III) oxide/Ag structure. Donor D18 and acceptor Y12 have complementary absorption spectra covering the visible range (300–800 nm). Furthermore, the energy layer alignment of these materials also makes it easier for charge generation and transport. All these factors lead to exploiting the possibility of using these organic solar cells (OSCs) for indoor photovoltaic (IPV) applications. The devices prepared previously were soaked in light (AM1.5 G) and illuminated under three types of white LED: warm white, standard white, and cool white. The intensities of the lights were varied, and the photovoltaic parameters of the cells were recorded. The variation of photovoltaic parameters with the intensity and color-correlated temperature (CCT) of different lights was thoroughly studied in this work. The external quantum efficiency of devices was also recorded. Here, we obtained cells with a power conversion efficiency (PCE) of 12.88% in AM1.5 G, which went up to 27.58% in indoor lighting. All the devices were prepared without the nitrogen glovebox and were characterized in ambient conditions, which is the first step toward commercializing and integrating the cells in the Internet of Things (IoTs). IPV, being an emerging field, the study of photovoltaic parameters under varied intensity of light and different lights reveals a lot of information about the behavior of cells. Such a study has never been performed before, and the correlation between intensity and CCT of light with photovoltaic parameters and PCE unveils invaluable information about indoor OSCs. The results of this study could potentially aid in optimizing and developing OSC for self-sustaining IoTs in the near future.