Flexible double narrowband near-infrared photodetector based on PMMA/core-shell upconversion nanoparticle composites

Abstract Flexible narrowband near infrared (NIR) photodetectors (PDs) are urgently in demand in the fast-developing era of flexible electronics, due to their crucial roles in various innovative applications. Hence, we designed and synthesized the core-shell structure NaYF4:Yb3+,Er3+@NaYF4:Nd3+ upconversion nanoparticles (UCNPs), which can be pumped by the 808 and 980 nm light. The upconversion luminescence (UCL) were significantly enhanced after assembling with the opal photonic crystals (OPCs) due to the photonic crystal effect, with 55 and 48 folds of enhancement factors under illuminations of 808 and 980 nm light, respectively. Based on this hybrid, the flexible narrowband PDs were successfully fabricated on the PET substrate with the structure of OPCs/NaYF4:Yb3+,Er3+@Nd3+/MAPbI3, which displayed excellent detect performance to double narrowband NIR light (808 and 980 nm) benefiting from the amplified UCL, with responsivity of 8.79 and 7.39 A/W, detectivity of 3.01 × 1011 and 2.68 × 1011 Jones for 808 and 980 nm light detection respectively, along with short response times in the range of 120–160 ms. Furthermore, the OPCs/NaYF4:Yb3+,Er3+@NaYF4:Nd3+/MAPbI3 double narrowband PDs displayed low photodetection power threshold (0.05 W/cm2), outstanding flexibility, prominent moisture resistance, and good long-time stability. This work displayed a new concept of narrowband NIR PDs, which opens a new field for specific NIR light detections.