Luminescent Waveguides In-situ Integrated with Organic Solar Cells for Internet of Things

Transparent electronics offer exciting light harvesting solutions for generation of electrical power via demonstration of "see-through" optoelectronic devices. The wireless energy harvesting ability can empower unplugged and battery-free operations for Internet of Things (IoT) devices. In this study, we report a transparent, luminescent, and elastomeric optical waveguide incorporating quantum dots that is in-situ coupled with organic solar cell array made of P3HT:PC61BM bulk heterojunction. CdSe@ZnS QDs have a photoluminescence quantum yield (PLQY) of 91% and are synthetically engineered to match their photoluminescence spectra with the photo-response of P3HT:PC61BM solar cells for efficient energy harvesting. Integrated devices can generate sufficient power for the active radio frequency identification (RFID) tags to send signals in the communication distance of 35 meters at low illumination level of 0.1-sun and ~0.1 km under 1-sun condition, respectively, which is sufficient for indoor and outdoor communications. Advantageously, the combination of organic solar cells with the waveguide during the elastomer curing leads to the elimination of the undesired post-fabrication processes such as alignment of the solar cells with waveguide and gluing the separate parts with curable polymers. This study paves the way toward using luminescence as transparent, efficient, and configurable energy harvesting solutions for IoT applications.