4.1 Film deposition methods
The morphology can be significantly influenced by the deposition method
used to film processing.[88] Different deposition methods, generally
including spin-coating, blade-coating and slot-die (Figure 2), can lead
to different structures and packing arrangements of the molecules, which
can affect the device performance. For example, spin-coating spreads
solution on the substrate then quickly shakes off the solution by the
centrifugal force, which can form a relatively smooth and uniform film
with small crystalline domains.[89]
Blade-coating and
slot-die use the shear force formed
by bending liquid surface to coat the solution on the substrate, which
have a certain induction effect on the aggregation and arrangement of
solute molecules.[90, 91] In addition, there are some new
film-forming methods, such as meniscus-assisted-coating (Figure 2d).