Rationalizing the Spatial Charge Distribution Modulation of Carbazole‐Based Additives for Efficient Perovskite Quantum Dots Light‐Emitting Diodes

ABSTRACT

Achieving efficient perovskite light‐emitting diodes (PeLEDs) requires the simultaneous suppression of surface defects and regulation of carrier transport, yet integrating these functions within a single molecular design remains challenging. Here, three carbazole‐based molecules were introduced during the synthesis of FAPbBr ₃ perovskite quantum dots (PQDs). Complementary FTIR and XPS analyses reveal carbazole‐derived vibrational features and additive‐dependent perturbations of the nitrogen and lead electronic environments, establishing a comparative sequence of molecular association with the PQD surface. Among the three additives, 3,6‐bis(9‐carbazolyl)‐9‐methylcarbazole (MCP) exhibits the most negative calculated adsorption energy and the largest N 1s and Pb 4f binding‐energy shifts, consistent with the strongest interfacial electronic interaction. This pronounced interfacial interaction is accompanied by the most substantial improvements in the photophysical characteristics of the PQDs and the electroluminescent performance of the resulting PeLEDs. The extended π‐conjugated framework further facilitates interfacial charge transport and radiative recombination in green‐emissive PeLEDs. As a result, MCP‐based PeLEDs exhibit an enhanced peak external quantum efficiency from 11.77% to 19.43%, together with a maximum luminance of 46434 cd/m ² . This work clarifies the molecular‐level role of spatial charge distribution in carbazole‐based additives and provides a rational guideline for designing multifunctional passivators for green PQD‐based PeLEDs.