Perspectives and challenges in circularly polarized luminescence of lanthanide(III) complexes: From solution-based systems to solid-state applications

This review provides a comprehensive examination of circularly polarized luminescence (CPL) in Lanthanide(III) systems, encompassing their historical development, present challenges, and future applications. Starting with early discoveries and key milestones, we trace the evolution of CPL studies, highlighting seminal works and breakthroughs that have shaped current understanding. Special emphasis is placed on the processing of these complexes in both solution and solid-state forms, delineating how different environments affect CPL properties. We delve into the challenges that researchers face in this field, including synthetic hurdles, stability issues, and the need for enhanced dissymmetry factors and emission quantum yields. Additionally, the review explores strategies to overcome these obstacles, such as innovative coordination chemistry design, advanced characterization techniques, and novel processing methods. Finally, we discuss potential applications of Lanthanide(III) CPL complexes, from security and display technologies to biological fingerprint. By providing a historical perspective, identifying current challenges, and outlining future directions, this review aims to serve as a valuable resource for researchers and practitioners in the field of luminescent materials and beyond.