Heavy-Metal-Free Flexible Hybrid Polymer-Nanocrystal Photodetectors Sensitive to 1.5-µm-wavelength

Photodetection in the short-wave infrared (SWIR) wavelength window represents one of the core technologies allowing for many applications. Most current photodetectors suffer from high cost due to the epitaxial growth requirements and the ecological issue due to the use of highly toxic heavy-metal elements. Toward an alternative SWIR photodetection strategies, in this work, high-performance heavy-metal-free flexible photodetectors sensitive to λ = 1.5 µm photons are presented based on the formation of a solution-processed hybrid composing of a conjugated diketopyrrolopyrrole-base polymer/PC70BM bulk heterojunction organic host together with inorganic guest NaYF4:15%Er3+ upconversion nanoparticles (UCNPs). Under the illumination of λ = 1.5 µm SWIR photons, optimized hybrid BHJ/UCNP photodetectors exhibit a photoresponsivity of 0.73 mA/W and 0.44 mA/W respectively for devices built on rigid ITO/glass and flexible ITO/polyethylene terephthalate (PET) substrates. These hybrid photodetectors are capable of perf...