A new series of new multifunctional materials with the azo-group in the molecular core has been prepared, which exhibit ferroelectric properties and are photosensitive. With these materials (known as photoferroelectrics) the illumination by visible light can change their electric and optical properties. After the light is switched off their properties are restored to the original state. Such materials offer a series of applications in optoelectronics or photonics. Besides, the studied compounds exhibit a low shrinkage of the smectic layer at the phase transition to the ferroelectric state, which makes them quite unique. Due to this effect specific defects that arise during the sample preparation and significantly degrade their properties can be eliminated. It has been found that variation of the length of the non-chiral chain joined to the molecular core can optimize photoferroelectric properties as well as layer shrinkage of the studied materials (see
V. Novotná a kol., J. Mater. Chem. 19, 3992-3997 (2009)).
