Lead halide perovskites are intensively studied in past few years due to their
potential applications in optoelectronic devices such as solar cells, photodetectors,
light-emitting diodes (LED), and lasers. In addition to the rapid
developments in material synthesis and device fabrication, it is also very
interesting to postsynthetically control the optical properties with external
irradiations. Here, the influences of very low energy (10–20 keV) electron
beam of standard electron beam lithography are experimentally explored on
the properties of lead halide perovskites. It is confirmed that the radiolysis
process also happens and it can selectively change the photoluminescence,
enabling the direct formation of nanolaser array, microsized light emitter
array, and micropictures with an electron beam writer. Interestingly, it is
found that discontinuous metallic lead layers are formed on the top and
bottom surfaces of perovskite microplate during the radiolysis process, which
can act as carrier conducting layers and significantly increase the photocurrent
of perovskite photodetector by a factor of 217%. By using the electron
beam with low energy to modify the perovskite, this method promises to
shape the emission patterns for micro-LED with well-preserved optical properties
and improves the photocurrent of photodetector.