Femtosecond Laser Induced Nucleation And Growth Of Organic Crystals

Organic semiconductor optoelectronic devices have been widely used worldwide due to their simple structure,applicability to flexible scenarios,and compliance with environmental development concepts.However,currently,amorphous materials mainly used in organic photoelectric devices have low mobility,and disordered structures and defects become traps and scattering centers for bound excitons,limiting photoelectric conversion efficiency.Organic semiconductor single crystal materials have a highly ordered molecular arrangement,which has broad application prospects in the field of high-performance optoelectronic devices.However,in the current commonly used crystal growth methods(including physical vapor transport and solution treatment),it is difficult to control the nucleation position of crystal formation,which brings difficulties to the preparation of organic crystal devices.This thesis proposes to use femtosecond laser induced cavitation to induce solute aggregation in organic semiconductor solutions,regulate local supersaturation,and achieve in situ nucleation and crystallization of organic crystals.In addition,this paper also explores femtosecond laser induced crystal growth,femtosecond laser induced solute aggregation,and laser scanning to control crystal morphology.The observation of femtosecond laser induced crystallization of organic semiconductor materials from perylene and red fluorene respectively confirms that this method is suitable for different materials.By controlling the precursor solution morphology,laser action mode,laser energy,and action time,the number of nuclei and crystal morphology of femtosecond laser induced organic semiconductor crystals can be effectively controlled,which is more efficient and controllable than traditional processes.In addition,this paper also used visual silver chips to observe in situ the process of material aggregation in solution induced by femtosecond laser irradiation,and elaborated the physical mechanism of femtosecond laser cavitation induced crystallization of perylene.This is of great help for future research on the application of this method to other materials.This paper provides an effective scheme for the in situ growth of organic single crystals and their application to optoelectronic devices.