Synthesis And Properties Of N-C=O Based Dynamic Resonance Organic Photoelectric Materials

Organic optoelectronic materials are widely used in various fields such as organic light-emitting diodes（OLEDs）,perovskite solar cells（PSCs）,information encryption and storage due to their unique optoelectronic characteristics.Among numerous organic optoelectronic materials,organic dynamic resonance materials can regulate the absorption,optical band gap and electrical characteristics of materials through resonance variation to obtain excellent photoelectric properties,thus showing great potential application in many fields.This kind of material,when served as host in OLEDs,is able to redistribute charge via resonance variation,which can realize the balance of the carrier transport for improving the device performance.For organic ultralong afterglow,organic dynamic resonance materials can enhance the spin orbit coupling constant（SOC）through resonance variation to boosting the afterglow properties.When these materials are used in PSCs,the resonance groups can passivate the defects in perovskite and improve the performance of PSCs.Benefiting from the superiority of resonant materials in excited state and electrical property modulation,in the thesis,we designed and synthesized a series of organic photoelectric materials based on N-C=O resonance structure,and systematically studied their performance in photoactivated ultralong afterglow material system and perovskite solar cell devices.The specific research works are as follows:（1）Synthesis and properties of photo-activated ultralong afterglow materials based on N-C=O dynamic resonance structureHere,a series of N-C=O dynamic resonance materials were designed and fabricated to achieve the fast reversible photoactivated ultralong afterglow system via a simple doping strategy.The SOC of the materials is enhanced effectively by a fast and effective resonance variation（N-C=O）process.Besides,polymer matrix is used to isolate the water and oxygen,and the material experiences the photo-activated process from none afterglow to ultra-long afterglow.The photo-activated ultralong afterglow properties of the materials were systematically studied by combining experiments and theory calculations.These materials can respond quickly under the excitation of low power ultraviolet lamp.After 30 s irradiation,the obvious afterglow phenomenon appears,and reaches the saturated afterglow emission intensity within 180 s.Under the excitation of high power ultraviolet,they can even reach the saturation state within 30 s.And,the afterglow lifetime can be up to 508 ms,which is nearly 145 times than that of the initial value.Moreover,they can be restored to their initial state after being left in a natural environment for 120 min or heated at 50℃for 30 s.In addition,we have verified that the dynamic resonance structure is beneficial to improve the SOC of the materials to enhance the afterglow performance after photoactivation through theoretical calculation.Due to the excellent photoactivation afterglow properties of these dynamic resonant materials,they have been successfully applied in the fields of optical printing and dynamic information encryption.（2）Preparation of multiplex N-C=O dynamic resonance materials and their application in perovskite antisolvent solute materialsHere,two kinds of multiple N-C=O structural resonance materials were designed and constructed,and their thermodynamic properties,photophysical properties,as well as electrical properties were characterized.Then,they were successfully applied to organic PSCs by anti-solvent additive engineering（AAE）,and the device performance was systematically studied.As the resonance structure of the developed materials would distribute charge through resonance variation,partly forming N⁺=C-O^–resonance structure,which can interact strongly with Pb²⁺to dynamically passivate defects and induce directional crystallization of perovskite.As a result,the high-quality perovskite thin film is prepared,and power conversion efficiency（PCE）of the PSCs are largely improved;the highest PCE value is up to 17.76%.The work in this chapter not only paves the way to broaden the application of organic dynamic resonance materials,but also provides a new way to improve the device performance of PSCs.