天津大学封伟团队报道了液晶模板手性钙钛矿量子点的机械可调谐圆偏振发光。相关研究成果发表在2024年3月25日出版的《德国应用化学》。

赋予钙钛矿量子点（PQDs）具有圆偏振发光（CPL）的为创新的手性光学应用提供了巨大的前景，但现有的策略在获得具有大的、可调的不对称因子（glum），和长期稳定性的刺激响应柔性手性钙钛矿膜方面效率低下。

该文中，研究人员报道了一种设计和合成具有机械可调CPL的发光胆甾醇液晶弹性体（Lumin CLCE）膜的策略，这是通过液晶模板手性自组装和明智设计的可光聚合CsPbX₃（X=Cl，Br，I）PQD纳米单体，到弹性聚合物网络中的原位共价交联实现的。

由此产生的Lumin CLCE薄膜在自然光下显示出圆偏振的结构色，在紫外线下显示出显著的CPL，最大glum值高达1.5。CPL强度和旋转方向的操纵，是通过控制自组装的螺旋纳米结构和软螺旋的手性来实现的。

该研究实现了一种通过双轴拉伸激活的可逆、机械可调谐的基于钙钛矿的CPL开关，该开关能够实现灵活、动态的防伪标签，能够在特定的极化状态下解密预设信息。

该项工作可以为先进手性钙钛矿材料的开发，及其在信息加密、柔性3D显示器等领域的新兴应用提供新的见解。

附：英文原文

Title: Mechanically Tunable Circularly Polarized Luminescence of Liquid Crystal-Templated Chiral Perovskite Quantum Dots

Author: Xuan Zhang, Lin Li, Yuanhao Chen, Cristian Valenzuela, Yuan Liu, Yanzhao Yang, Yufan Feng, Ling Wang, Wei Feng

Issue&Volume: 2024-03-25

Abstract: Endowing perovskite quantum dots (PQDs) with circularly polarized luminescence (CPL) offers great promise for innovative chiroptical applications, but the existing strategies are inefficient in acquiring stimuli-responsive flexible chiral perovskite films with large, tunable dissymmetry factor (glum) and long-term stability. Here, we report a strategy for the design and synthesis of luminescent cholesteric liquid crystal elastomer (Lumin-CLCE) films with mechanically tunable CPL, which is enabled by liquid crystal-templated chiral self-assembly and in situ covalent cross-linking of judiciously designed photopolymerizable CsPbX3 (X = Cl, Br, I) PQD nanomonomers into the elastic polymer networks. The resulting Lumin-CLCE films showcase circularly polarized structural color in natural light and noticeable CPL with a maximum glum value up to 1.5 under UV light. The manipulation of CPL intensity and rotation direction is achieved by controlling the self-assembled helicoidal nanostructure and the handedness of soft helices. A significant breakthrough lies in the achievement of a reversible, mechanically tunable perovskite-based CPL switch activated by biaxial stretching, which enables flexible, dynamic anti-counterfeiting labels capable of decrypting preset information in specific polarization states. This work can provide new insights for the development of advanced chiral perovskite materials and their emerging applications in information encryption, flexible 3D displays and beyond.

DOI: 10.1002/anie.202404202

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202404202