Multiphoton Excited SingletTriplet Mixed Self-Trapped Exciton emission

Multiphoton excited singlet/triplet mixed self-trapped exciton (MSTSE) emission is a phenomenon that occurs in certain organic and inorganic materials when they are excited by high-intensity laser light. When the material absorbs multiple photons, the excited state of the molecule can become self-trapped, meaning that the molecule becomes distorted and its electrons become localized in a small region of space. This self-trapped state can exist in either a singlet or triplet configuration, depending on the spin of the electrons.

In the case of MSTSE emission, the singlet and triplet states of the self-trapped exciton can mix together, creating a hybrid state. This hybrid state has unique photophysical properties, including a longer lifetime and a broader emission spectrum than either the singlet or triplet states alone. This makes MSTSE emission useful for a variety of applications in photonics and optoelectronics, including as a light source for microscopy and imaging, as well as for the development of new types of organic light-emitting diodes (OLEDs)