Lead sulfide colloidal quantum dot photovoltaic cell for energy harvesting from human body thermal radiation

In this paper, we present the development of a solution-processed photovoltaic structure designed to convert human body thermal radiation into electricity. An active layer composed of a layer of isopropylamine-capped lead sulfide (PbS) quantum dots (QDs) covered with a layer of lithium chloride (LiCl) on top is sandwiched between a substrate and an aluminum contact. Experimental measurements reveal that the device was sensitive to infrared radiation with energies lower than the optical bandgap energy of the incorporated nanocrystals (E-g = 1.26 eV), allowing one to harvest thermal radiation from a human body. We used a conceptually different approach to harvest this radiation by intentionally introducing mid-gap states to the lead sulfide quantum dots through passivation with isopropylamine and likely enabling a multi-step photon absorption mechanism.