Akademik Veri Yönetim Sistemi
Dyes and Pigments, cilt.251, 2026 (SCI-Expanded, Scopus)
The photophysical process of intersystem crossing (ISC), enabling conversion between spin-forbidden singlet and triplet states is a cornerstone of photochemistry and materials science. Typically, ISC is considered a static molecular property. However, recent advancements have demonstrated that ISC can be dynamically and reversibly switched on and off, or its rate finely tuned in response to various external stimuli. This control is achieved through strategies such as changing medium rigidity, solvent microenvironment, or inducing molecular conformational changes, which can significantly perturb internal molecular dynamics on ultrafast timescales. This paradigm shift towards switchable ISC opens a new frontier in the design of smart materials, enhanced biological imaging techniques, targeted photodynamic therapies and adaptive organic electronic devices. Based on direct singlet-to-triplet ISC and charge transfer-mediated ISC mechanisms, herein, we outline the experimental and theoretical photophysical fundamentals governing ISC. The diverse strategies for achieving ISC switchability, with focus on microenvironmental modulation by medium rigidity, solvent polarity and molecular geometrical changes, are discussed. Femtosecond transient absorption spectroscopic technique is widely used to probe the effect of external stimuli on real-time singlet-triplet transient dynamics at ultrafast timescales. We conclude that external stimuli drastically change the charge transfer or ISC efficiency and dynamics, and further perspectives on the challenges and opportunities are also covered.