Energy‐Harvesting Blue Color Filters for Organic Light‐Emitting Diodes

Abstract Color filters are essential components to realize next‐generation applications based on organic light‐emitting diodes (OLEDs), such as flexible displays and multipurpose lighting. Although the most widely used color filters that include dyes and pigments have advantageous features, such as their simplicity and color purity, the energy wasted by these color filters does not meet the needs for a green and sustainable future. This paper presents a fullerene‐free organic solar cell (OSC) color filter that is not only a highly effective blue color filter, owing to its ability to absorb green and red light, but also functions as an energy‐harvesting device. OLED‐OSC tandem devices with the two distinct functions of OLED and OSC within one device are successfully demonstrated. The OSC of the tandem device generates electrical energy with a power conversion efficiency of 6.83%. The OLED of the tandem device emits blue light with a maximum luminance of 1400 cd m⁻², and the International Commission on Illumination (CIE) chromaticity is dramatically tunable from (0.34, 0.36) to (0.14, 0.17).