Dual Passivation Strategy for Highly Stable Blue-Luminescent CsPbBr Nanoplatelets.

Blue-emitting colloidal CsPbX (X = Br, Cl, or I) perovskite nanocrystals have emerged as one of the most fascinating materials for optoelectronic applications. However, their applicability is hindered by poor stability and a low photoluminescence efficiency. Herein, highly stable CsPbBr nanoplatelets exhibiting intense blue luminescence are fabricated by employing a strategy in which the morphology is regulated and the surface is subjected to dual passivation through the incorporation of zirconium acetylacetonate [Zr(acac)]. The passivated CsPbBr nanocrystals exhibit adjustable light emission from green to dark blue and a controllable morphology from nanocubes (NCs) to nanoplatelets (NPLs) and nanorods accomplished by varying the content of Zr(acac). The optimized NPLs are characterized by a bright blue emission with a central wavelength of 459 nm and a high photoluminescence quantum yield of 90%. The addition of Zr(acac) in the synthesis of CsPbBr induces oriented growth with a two-dimensional morphology. The Zr(acac) can repair the surface defects of the nanocrystal surface, and the surface is also capped with the Zr(OH) cluster layer. Therefore, the passivated blue-emitting NPLs exhibit outstanding stability compared to that of pristine NPLs during long-term storage and exposure to light. This work provides a novel strategy for fabricating highly stable PNCs with deep-blue emission and widens their potential applications in blue-emitting optoelectronic devices.