  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.
