Near-infrared to visible light optical upconversion by direct tandem integration of organic light-emitting diode and inorganic photodetector

The authors report a hybrid organic/inorganic optical upconversion device that converts $1.5\mu \mathrm{m}$ infrared light to $\sim 520\mathrm{nm}$ visible light. The device was made by direct tandem integration of an inorganic $\mathrm{In}\mathrm{Ga}\mathrm{As}∕\mathrm{In}\mathrm{P}$ photodetector with an organic light-emitting diode (OLED). Optical upconversion with an external efficiency of 0.7% W/W at room temperature has been achieved. Interfacial structure at the inorganic-organic interface was found to play a vital role in enabling the integration of the hybrid tandem upconverter. Both sulfur-terminated InP surface and nanocarbon fullerene interlayer were found crucial to form a good interface contact, permitting continuous flow of photocarriers from the inorganic detector into the OLED.