Hot electrons in carbon nitride with ultralong lifetime and their application in reversible dynamic color displays

Plasmonic colors enabled by resonant hot electrons offer unique advantages in imaging, display, and optical encryption applications. Although metasurfaces can show full colors with sub-wavelength spatial resolutions, it is challenging for them to generate dynamic colors. Herein, we report an approach to dynamically control the color of semiconducting nanoparticles with plasmonic properties by tuning their hot-electron lifetime from timescales of seconds to days. The color switch is realized by storing photogenerated electrons, which produce plasmons upon light excitation, in carbon nitride. A photochromic display based on long-lived hot electrons is demonstrated. Two-dimensional patterns with unlimited designs and feature sizes from micro- to macro-scale are generated through laser writing or photolithography and then can be erased by exposure to moisture or heat, hundreds of times without obvious destruction to the device. This work may expand the possibilities of using hot electrons for reversibly manipulating the colors of semiconductor nanoparticles with plasmonic properties.