Suppressed Photoluminescence Blinking and Enhanced Stability in Ligand-Engineered Pure Blue-Emitting Perovskite Nanocrystals

Metal-halide perovskites have emerged as a promising light-emitting material, yet achieving efficient and stable blue emission remains a challenge. Moreover, colloidal nanocrystals (CNCs) synthesized via the hot-injection method lose much of their emission quality upon film formation. In this work, we present a one-step spin-coating strategy to grow blue-emitting cube-like CsPb(Cl/Br)₃ nanocrystals (NCs) directly on a substrate. We achieve this by synergistically integrating sterically hindered short conjugated 1-(4-bromophenyl)ethanammonium (Br-MBA⁺) ligands, which effectively suppress the formation of low-dimensional layered phases. The resulting grown-on-substrate NCs (SNCs) exhibit a photoluminescence (PL) emission peak around 460 nm with Commission Internationale de l'Éclairage (CIE) coordinates of (0.14, 0.045), closely matching the Rec. 2100 pure blue standard (0.131, 0.046). The SNCs capped with Br-MBA⁺ ligands exhibit higher photoluminescence quantum yields and improved stability compared to CNCs capped with oleic acid/oleylamine ligands and quasi-two-dimensional perovskites. Furthermore, single-particle PL microscopy reveals that the SNCs exhibit significantly suppressed PL blinking, pronounced photoenhancement, and enhanced photostability compared to CNCs, even under high excitation power. These improvements arise from the strong binding affinity of Br-MBA⁺ ligands, which effectively reduce the formation of surface defects and long-lived nonradiative traps, thereby prolonging radiative lifetimes. Altogether, our work demonstrates the direct growth of blue-emitting cube-like perovskite NCs on a substrate using conjugated ligands and provides a systematic investigation of their PL blinking characteristics, yielding stable and efficient pure blue-emitting perovskite NCs.