A hidden chemical assembly mechanism: reconstruction-by-reconstruction cycle growth in HKUST-1 MOF layer synthesis

Abstract

Thin metal-organic framework films grown in a layer-by-layer manner have been the subject of growing interest. Herein we investigate one of the most popular frameworks, type HKUST-1. Firstly, we show a synthesis procedure resulting in quick but optically perfect growth. This enables the synthesis of films of excellent optical quality within a short timeframe. Secondly and most importantly, we address the already known, but not fully understood observation that the expected monolayer growth is strongly exceeded in every single deposition cycle. This is an often-ignored contradiction in the literature. We offer a growth model using mid-cycle reconstruction process leading to a mathematically determined reconstruction-by-reconstruction (RbR) cycle growth with a 4-times higher growth rate representing an up-to-now hidden chemical assembly mechanism.