Multiscale Theoretical Insights into Heteroatom Effects in Organic Optoelectronic Materials: Dynamic Competition Between Lone‐Pair Electrons and Electronegativity

Although heteroatom doping is widely used to regulate the device performance of organic optoelectronic materials, it remains unclear how heteroatoms utilize their intrinsic properties, such as lone-pair electrons and electronegativity, to control the interfacial dynamics and morphological evolution mechanisms. This study systematically investigates the dual-heteroatom effect in Y-series acceptors with tailored end groups using a multiscale approach combining density functional theory, molecular dynamics simulations, and machine learning. The structural truncation strategy isolates the conjugation effect (via lone-pair electrons) from the induced effect (via electronegativity), and the results indicate that the sulfur-terminal acceptor (Y-ICTh) achieves optimal donor-acceptor blending due to the lone-pair conjugation effect is enhanced while the electronegativity-induced effect is suppressed. In addition, the heteroatom effect can subtly regulate the hybridization between the charge transfer state and the local excited state, potentially reducing energy loss. And the correlation between the stacking parameter and the energy of the charge transfer state is found by machine learning, revealing the role of the heteroatom effect and the stacking coherence as a key predictor. This work uniquely links atomic-scale heteroatom effects to macroscopic device performance, providing a dual channel design strategy for efficient optoelectronic materials by balancing the dual effects in heteroatom engineering.