Sensitized triplet-triplet annihilation-based photon upconversion: Assembly strategy and key consideration for sustainable energy and biomedical applications

Sensitized Triplet-triplet annihilation (sTTA) photon upconversion (UC) represents a cutting-edge technology with far-reaching implications in both sustainable energy and biomedical realms. By capitalizing on the unique properties of excited triplet states, sTTA-UC enables the conversion of low-energy photons into higher-energy counterparts, offering promising solutions for efficient solar energy utilization and transformative biomedical applications. This review offers a comprehensive exploration of sTTA-UC, delving into its fundamental principles, assembly strategies, and key considerations for applications in sustainable energy and biomedicine. Various materials, including silica, clay, polymers, gels, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs), play integral roles in enhancing sTTA efficiency and overcoming challenges such as oxygen quenching. Additionally, the review surveys the diverse applications of sTTA-UC, in photocatalysis, solar energy conversion, biosensing, bioimaging, and therapeutic interventions. These applications underscore the versatility and potential of sTTA-UC across multifaceted domains, promising significant advancements in various scientific and technological fields. Looking towards the future, the review outlines key areas for further exploration and development in sTTA-UC research. Priorities include optimizing materials, enhancing stability, and exploring innovative integration approaches to fully harness the capabilities of sTTA-UC technology. By elucidating the opportunities and challenges inherent in sTTA-UC, this review seeks to inspire researchers to propel the field forward, driving innovation and sustainability in both energy and biomedical sectors.