Photoswitchable nonlinear optical properties of metal complexes

Incorporating photosensitive molecules into the organic/inorganic hybrid materials can contribute to forming photoresponsive systems. The second/third-order nonlinear optical properties can be changed via external light stimulation at an appropriate wavelength. The photochromic metal complexes appear to be superior promising materials in the domain of photoswitchable nonlinear optics (NLO). Thus, the purpose of this review is to examine current progress of metal complexes in the field of photoswitchable NLO materials and provide perspectives for the future. The overview includes the second-order and third-order NLO photoswitches and NLO properties of metal complexes. Combined with the characteristics of pyrene and stilbazolium groups, we describe a new type of photoswitchable NLO materials. The rapidly increasing investigations in this domain suggest that NLO photoswitches of metal complexes would play a critical role for inspiring applications in the future. Incorporating photosensitive molecules into the organic/inorganic hybrid materials can contribute to forming photoresponsive systems.