Highly Efficient Top-Emitting Infrared-to-Visible Up-Conversion Device Enabled by Microcavity Effect

摘要

Infrared (IR)-to-visible up-conversion device allows a low-cost, pixel-free IRimaging over the conventional expensive compound semiconductor-based IRimage sensors. However, the external quantum efficiency has been low dueto the integration of an IR photodetector and a light-emitting diode (LED).Herein, by inducing a strong micro-cavity effect, a highly efficient top-emittingIR-to-visible up-conversion device is demonstrated where PbS quantumdots IR-absorbing layer is integrated with a phosphorescent organic LED.By optimizing the optical cavity length between indium tin oxide (ITO)/thinAg/ITO anode and semi-transparent Mg:Ag top cathode, the up-conversiondevice yields 15.7 of photon-to-photon conversion efficiency from the topemission.The high efficiency can be achieved under a low IR transmissionthrough the semi-reflective anode. Finally, pixel-free IR imaging is demonstratedusing the up-conversion device, boosting the effect of micro-cavity onthe brightness and the contrast of an IR image.