Direct Writing Large-Area Multi-Layer Ultrasmooth Films by an All-Solution Process: Toward High-Performance QLEDs

With increasing the film area/layer, deteriorating in both smoothness and uniformity of thin-films frequently happen, which remains a barrier for making large-area quantum dot light-emitting diodes (QLEDs) by solution processes. Here, we demonstrated a facile all-solution process guided by the conical fiber array to write multi-layer ultrasmooth thin-films directly in centimeter scale. The side-by-side fibrous array helps to align surface tensions at the tri-phase contact line to facilitate large-area homogeneous deposition, which was verified by theoretical simulation. The Laplace pressure along individual conical fiber contributes to the steady liquid transfer. Thin-films with small roughness (<2.03 nm) and large-area (2x2 cm(2)) uniformity were prepared sequentially on the target substrate, leading to large-area high-performance QLEDs. The result offers new insights for fabricating large-area high-performance thin-film devices.

Automated summary

This study demonstrates a simple all-solution process guided by a conical fiber array to write multi-layer ultrasmooth thin-films directly in centimeter scale. The use of a fibrous array helps align surface tensions for large-area homogeneous deposition, leading to the preparation of thin-films with small roughness and large-area uniformity, which subsequently enables the fabrication of large-area high-performance QLEDs.