Manipulating solvent fluidic dynamics for large-area perovskite film-formation and white light-emitting diodes
Guangyi Shi, Zongming Huang, Ran Qiao, Wenjing Chen, Zhijian Li, Yaping Li, Kai Mu, Ting Si, Zhengguo Xiao
Abstract
Abstract Presynthesized perovskite quantum dots are very promising for making films with different compositions, as they decouple crystallization and film-formation processes. However, fabricating large-area uniform films using perovskite quantum dots is still very challenging due to the complex fluidic dynamics of the solvents. Here, we report a robust film-formation approach using an environmental-friendly binary-solvent strategy. Nonbenzene solvents, n-octane and n-hexane, are mixed to manipulate the fluidic and evaporation dynamics of the perovskite quantum dot inks, resulting in balanced Marangoni flow, enhanced ink spreadability, and uniform solute-redistribution. We can therefore blade-coat large-area uniform perovskite films with different compositions using the same fabrication parameters. White and red perovskite light-emitting diodes incorporating blade-coated films exhibit a decent external quantum efficiency of 10.6% and 15.3% (0.04 cm 2 ), and show a uniform emission up to 28 cm 2 . This work represents a significant step toward the application of perovskite light-emitting diodes in flat panel solid-state lighting.