Achieving Over 30% Photon-to-Photon Efficiency with Tandem OLED Structures in Organic Upconversion Devices

Abstract

Infrared upconversion imaging technology significantly simplifies the complex structures of conventional infrared imaging systems, showcasing advantages in low cost, ease of manufacturing, and suitability for large-scale production, thereby holding tremendous potential for applications in fields such as infrared detection and biological imaging. However, current upconversion devices generally have a photon-to-photon conversion efficiency (ηp-p) of less than 20%. This study innovatively uses a tandem OLED as the emission unit, effectively enhancing the recombination efficiency of photogenerated carriers across different OLED units and significantly boosting luminous efficiency, achieving a stable ηp-p of over 20%, with a peak at 31.8%. Additionally, the device maintains a wide luminance linear dynamic range (L-LDR) of 91.61 dB and successfully achieves high-quality upconversion imaging of biological specimens. Through a newly designed imaging optical path, this work effectively realizes upconversion imaging of reflected light from sample surfaces, demonstrating the potential of tandem OLED structure in enhancing the performance of upconversion devices and paving new research directions for future high-efficiency imaging technologies.