  Metal-organic framework (MOF) thin-films show unmatched promise as smart
membranes and photo-catalytic coatings. However, their nucleation and growth
resulting from intricate molecular assembly processes are not well understood,
yet crucial to control the thin-film properties. Here, we directly observe the
nucleation and growth behaviour of HKUST-1 thin-films by real-time in-situ AFM
at different temperatures in the Cu-BTC solution. In combination with ex-situ
infrared (nano-)spectroscopy, synthesis at 25{\deg}C reveals initial nucleation
of rapidly growing HKUST-1 islands surrounded by a continuously nucleating, but
slowly growing HKUST-1 carpet. Monitoring at 13{\deg}C and 50{\deg}C shows the
strong impact of temperature on thin-film formation, resulting in (partial)
nucleation and growth inhibition. The nucleation and growth mechanisms as well
as their kinetics provide insights to aid in future rational design of MOF
thin-films.
