Through-space interactions of optoelectronic materials

In molecular science, theories based on covalent through-bond conjugation (TBC) serve as the foundational framework for designing efficient organic functional materials (OFMs). However, while TBC has been extensively established, through-space interaction (TSI) has recently emerged as an equally crucial electronic interaction governing the properties of OFMs, particularly in systems with partially or fully non-conjugated architectures. Nevertheless, the absence of quantitative structure-property relationships and a systematic summary continues to hinder the development of general design strategies for non-conjugated OFMs with tailored optoelectronic characteristics. Herein, this review presents a comprehensive overview of TSI in optoelectronic materials, beginning with its history, development, and current perspective. From the perspectives of luminescence and electronic properties, the working mechanisms, properties, manipulation strategies, and advanced applications of TSI are comprehensively summarized with typical examples, mainly including clusteroluminescence, thermally activated delayed fluorescence, room-temperature phosphorescence, and charge transport. Based on the current achievements and challenges, perspectives for the future development of TSI and related optoelectronic materials are also discussed. This review will facilitate the rational design of TSI-based optoelectronic materials and advance new photophysical theories as a supplement to the well-established TBC-based theories for next-generation functional materials.