Preface

Luminescence in its various forms has attracted the attention of different disciplines in the natural sciences for centuries. Ever since, fluorescence, as well as its longlived counterpart phosphorescence, has been used for multiple applications such as chemo/biosensing and bioimaging. The widely used conventional luminophores have suffered from the notorious aggregation-caused quenching effect, which results in decreased or completely quenched fluorescence once they are aggregated. In 2001, Ben Zhong Tang at the Hong Kong University of Science and Technology coined the concept of aggregation-induced emission (AIE), wherein some fluorogens showed extremely weak emission in molecular states but highly bright emission in the aggregate or solid states. This discovery is of great scientific value as a new theorem needs to be established to understand such an “abnormal” phenomenon; the new concept of AIE changes the way people think of the roles of aggregation in the light emission processes of luminogenic molecules. Due to its fundamental importance and practical implications, AIE has attracted much attention, as evidenced by the fact that hundreds of laboratories in over fifty countries are now carrying out AIE studies, leading to an exponential increase in the numbers of publications and citations on the topic...