While
halide perovskite X-ray detectors based on single crystals
could achieve extraordinary sensitivities, detectors based on polycrystalline
thick films lag behind in efficiency. This is unfortunate since the
processing methods for producing polycrystalline thick films, especially
by pressure treatment of powders, are suitable for upscaling. Here,
we investigate in detail the pressing of readily prepared powders
of methylammonium lead halide perovskites MAPbI3 and MAPbBr3 to thick layers. By time-dependent pressure measurements,
we monitor the occurring compaction dynamics, identifying two relaxation
processes with different timescales. When pressing at elevated temperatures
from room temperature (RT) to 100 °C, the pressure relaxations
change drastically. While the layer properties such as relative density
and surface roughness only improve to a certain degree by increasing
the pressure at RT, we observe relative densities >97%, considerable
reduction in surface roughness, and a significant increase in grain
size with tempered pressing. Analyses regarding time-dependent pressure
relaxations of tempered pressing allow attributing the dynamics to
a sintering process, where we find the sinter onset to be surprisingly
low at about 30 °C, mainly independent of the applied pressure
(10–100 MPa). Our results will allow for an improved and more
targeted powder processing of halide perovskite thick films as they
are promising candidates for efficient X-ray detectors.