Dynamic Chirality in Nature-Inspired Photonic Crystal Films: Ultralong Room Temperature Phosphorescence and Stimuli-Responsive Circularly Polarized Luminescence
Xiaolin Nie, Yue Zhang, Bo Wu, Ziyue Ye, Feng Gao, Yixuan Chen, Chunfeng Wang, Deliang Zhu, Parvej Alam, Zijie Qiu, Ben Zhong Tang
Abstract
Circularly polarized luminescence (CPL) systems exhibiting room-temperature phosphorescence (RTP) are attracting considerable attention for applications in information encryption and smart sensing. However, achieving ultralong circularly polarized RTP (CPRTP) with tunable chirality and stimuli-responsive CPL remains challenging. Inspired by the color-changing properties of the Troides magellanus butterfly, we developed a cellulose nanocrystal (CNC)-based photonic crystal film with an ultralong RTP lifetime of 2.04 s. The helical pitch of photonic crystal film could be engineered by adding different amounts of glucose, leading to 3-fold and 4-fold enhancement of the phosphorescence and fluorescence quantum yields, respectively, compared to the samples without glucose. The system exhibited green afterglows lasting over 4 s and tunable photonic bandgap (PBG) that modulated chiroptical properties, achieving high g lum values of −0.749 for fluorescence and −0.650 for phosphorescence. Additionally, the film demonstrated stimuli-responsive features such as humidity-responsive RTP and solvent-responsive CPL. Therefore, the biomimetic photonic crystal film offers promising opportunities for multilevel anticounterfeiting, information security, and smart sensing applications.