Inverse Solid‐State Photoluminescence and Electrochemiluminescence of Isostructural Nanoclusters: Unveiling the Critical Role of Intermolecular Charge Migration

Atomically precise metal nanoclusters are promising electrochemiluminescent (ECL) materials. However, the correlation between their solid‐state photoluminescence (PL) and ECL remains ambiguous, severely hindering the rational design of high‐performance solid‐state ECL materials. Herein, we report two nanoclusters, Au 5 Ag 13 (DPPP) 4 (C 6 F 5 S) 10 and [Au x Ag 17‐x ((DPPP) 5 (C 6 F 5 S) 8 ]SbF 6 , which share an identical Au 5 Ag 8 metal core but differ slightly in peripheral motifs, thus exhibiting a striking inverse solid‐state PL–ECL relationship. Single‐crystal structures and Hirshfeld surface analysis reveal that the stronger π–π interactions and higher molecular packing density in (AuAg) 18 facilitate efficient intermolecular electron transfer and charge migration, which are more critical than excited‐state generation and annihilation during the ECL process. This work demonstrates that charge transfer between nanoclusters and the electrode surface outweighs intrinsic excited‐state annihilation and decay in solid‐state ECL, providing a new mechanistic guideline for designing high‐performance ECL materials beyond the traditional pursuit of strong PL.