The development and utilization of luminescent molecules and materials have been a hot topic of research for many years. The development of quantum mechanics theory further advanced the study of luminescent materials by identifying its underlying origin in the electronic transition. Over the last couple of decades, molecules with diverse luminescent properties have been designed and developed to obtain luminophores with tailored emission and efficiency. This is mainly achieved by controlling the molecular conjugation through chemical design. Nonetheless, the applications of traditional fluorophores are rather limited due to their emission quenching in the solid state. To address this issue, luminophores with aggregation-induced emission (AIE) property have been widely studied an...[ Read more ]

The development and utilization of luminescent molecules and materials have been a hot topic of research for many years. The development of quantum mechanics theory further advanced the study of luminescent materials by identifying its underlying origin in the electronic transition. Over the last couple of decades, molecules with diverse luminescent properties have been designed and developed to obtain luminophores with tailored emission and efficiency. This is mainly achieved by controlling the molecular conjugation through chemical design. Nonetheless, the applications of traditional fluorophores are rather limited due to their emission quenching in the solid state. To address this issue, luminophores with aggregation-induced emission (AIE) property have been widely studied and explored. AIE luminophores (AIEgen) often exhibit enhanced or induced emission in the aggregated and condensed state which opens a possibility for various solid-state applications. Since the term AIE and AIEgen was coined in 2001, the AIE concept has expanded largely that nowadays a rich library of AIEgens with various emission color and efficiency are readily available for diverse applications.

One of the most distinct advantages of AIEgens is their emission in the solid state. To fully exploit this advantage, condensed materials that were previously not explored by fluorescent dyes offer promising potential. Therefore, to demonstrate the great benefits of AIEgens and to advance the research of luminescent studies, condensed materials can be explored by combining with AIEgens. Considering the functionality and practicality, polmer materials are a reasonable choice as they are widely used in our daily lives. Moreover, polymer materials possess excellent processability and can provide a good medium to encapsulate AIEgens. By combining AIEgen and polymer materials through blending or chemical bonding, a new class of material with amplified functionality could potentially be developed. Nonetheless, chemically attaching the luminogen into polymer requires tedious synthetis which could limit their large-scale applications. On the other hand, physical doping of AIEgen into polymer material provides a simple pathway to attain binary systems that could present amplified functions. In this thesis, my main goal is to present synergistic binary systems composed of polymer and AIEgens with simple fabrication yet with amplified functionalities.

When a binary system composed of polymer and AIEgen is prepared, the interaction between these two components can greatly affect the emissive property of the embedded AIEgen. Various interactions such as hydrophobicity, rigidification, and nano-confinement can trigger formation of certain AIEgen conformations. As a result, the embedded AIEgen functions a luminescent probe to convery invisible polymer information into visible fluorescent signals. In Chapter II and III, a single polymer matrix and a polymer blend was utilized as a continuous matrix to encapsulate microenvironment sensitive AIEgens. The emission-structure relationship of the AIEgens were firstly studied without the polymer matrix for understanding. In the Chapter II, crystalline and amorphous phases of a single polymer was employed to whereas in Chapter III different polymers with varying rigidity were employed to control the emissive property of the AIEgens. Moreover, such binary systems displayed an ability to generate circularly polarized light (CPL) which was explored in detail in Chapter IV. After establishing the underlying mechanism of this ability, a simple method to fabricate binary system with attunable CPL generation was proposed with experimental support in Chapter IV.