NIR to Visible Light Upconversion Devices Comprising an NIR Charge Generation Layer and a Perovskite Emitter

摘要

Near-infrared (NIR) to visible light upconversion is of significant importancein many applications, including thermal imaging, bioimaging, night vision,and wellness monitoring. Here, the effort to develop a high-performing NIRto saturated green light upconversion device comprising a front solutionprocessableorganic bulk heterojunction NIR charge generation layer (CGL)and an upper C_sPbBr_3 perovskite light-emitting diode (LED) unit is reported.The NIR CGL, based on a blend of the NIR-sensitive donor polymer and anonfullerene acceptor, enables an efficient hole injection in the CsPbBr3 LEDin the presence of the NIR light and also serves as an optical outcouplinglayer to enhance the visible light emission by the C_sPbBr_3 LED. The CsPbBr3-based perovskite LED has a narrow emission spectrum with a peak wavelengthof 520 nm, corresponding to the wavelengths near the peak responseof the human eye, and has the advantage in imaging applications. Based onthe upconversion process, a pixel-less NIR to visible light imaging device isdemonstrated, which can be operated at a low voltage of 3 V. The results arevery encouraging, revealing a high-performing solution-processable upconversiondevice for application in NIR light imaging.