Organic luminogens bearing alkyl substituents: design flexibility, adjustable molecular packing, and optimized performance

Abstract

For molecular engineering of organic luminogens, the utilization of different substituents is a common approach to tune their light emission properties. Unlike the well-recognized influence of aromatic substituents furnishing electron push–pull properties or steric hindrance on the luminescence properties, alkyl groups have attracted much less attention in most cases, regardless of their greater and greater importance to molecular packing appearing in recent years. In this review, we will give a summary of recent advances in organic luminogens modified with alkyl groups and their corresponding fluorescence, phosphorescence and/or mechano-responsive properties. Through systematical investigation of the relationship of the chemical structure–molecular packing–luminescence properties, some guidance is proposed for the rational molecular design of organic luminescent materials.