Design Of Colorful Organic Polymeric Afterglow Materials And Their Study On Energy Transfer And Chirality Transmission

Colorful organic afterglow materials have been widely applied in the field of colorful flexible displaying,multiple information encryption,polychromatic biological imaging agents and chemical sensing.Current approaches to tuning the color of organic afterglow have been mainly focused on regulating the molecular stacking motifs and changing the excitation wavelength.However,these methods require the complex molecular design and are difficult to realize full-color afterglow in visible-light range due to constrained emission adjustment.Therefore,it is an urgent need to explore efficient,concise and low-cost strategies to prepare colorful organic afterglow materials,which is of great scientific significance for excavating the deep practical value of organic afterglow.Based on that,this thesis is focused on the design and preparation for colorful organic afterglow materials and we obtained a series of colorful water-soluble polymer organic afterglow materials by using energy transfer strategy,and then further illustrated the energy transfer mechanism by investigating their emission spectrum,lifetime and photoluminescence quantum yield.Meanwhile,benefiting from the good water solubility,these materials are applied to printable multicolored data encryption and information security fields.The specific research content is shown as follows:（1）In order to realize the full-color organic afterglow materials and expand their applications,a series of polymeric afterglow systems whose luminescence color can be regulated on-demand are obtained by reasonable molecular design and energy transfer strategy,with afterglow lifetimes up to4.2 s and photoluminescence quantum yields of 36%.The photophysical properties of the materials were investigated through the analyses of luminescent spectra,luminescent lifetime and transient absorption.These results confirmed the effectiveness and universality of the phosphorescence F（?）rster resonance energy transfer strategy in the preparation for full-color long afterglow materials.Based on the color-tunable and water-processable properties,these materials have been successfully applied in the fields of colorful security printing and multiple information encryption.This research provides a simple,environment-friendly and efficient approach for the preparation of multicolor-emitting and high-performance organic afterglow materials,and also opens up a new way to broaden their practical applications.（2）To address the problem of luminescence color monotony of organic circularly polarized afterglow materials,in this chapter a strategy of dual transmission of both phosphorescence energy and chirality is proposed to prepare a series of colorful circularly polarized polymeric afterglow materials with phosphorescence lifetime up to 3 s and dissymmetric factor of 7.8×10^-3.The phosphorescence F（?）rster resonance energy transfer and chiral transmission processes in this host-guest system have been demonstrated by the investigations of transient spectra and circularly polarized luminescence spectra.This work employs chiral organic afterglow polymer as the host to sensitize the achiral fluorescent guest molecules,obtaining a great achievement in afterglow color regulation of organic circularly polarized afterglow materials,which not only provides feasible design ideas and research methods to construct high-performance and multifunctional organic afterglow materials but also paves the way to explore the new application of organic afterglow materials.