In terms of sustainable use, halide perovskite (HaP)
semiconductors
have a strong advantage over most other classes of materials for (opto)electronics,
as they can self-heal (SH) from photodamage. While there is considerable
literature on SH in devices, where it may not be clear exactly where
damage and SH occur, there is much less on the HaP material itself.
Here we perform “fluorescence recovery after photobleaching”
(FRAP) measurements to study SH on polycrystalline thin films for
which encapsulation is critical to achieving complete and fast self-healing.
We compare SH in three photoactive APbI3perovskite films
by varying the A-site cation ranging from (relatively) small inorganic
Cs through medium-sized MA to large FA (the last two are organic cations).
While the A cation is often considered electronically relatively inactive,
it significantly affects both SH kinetics and the threshold for photodamage.
The SH kinetics are markedly faster for γ-CsPbI3and
α-FAPbI3than for MAPbI3. Furthermore,
γ-CsPbI3exhibits an intricate interplay between
photoinduced darkening and brightening. We suggest possible explanations
for the observed differences in SH behavior. This study’s results
are essential for identifying absorber materials that can regain intrinsic,
insolation-induced photodamage-linked efficiency loss during its rest
cycles, thus enabling applications such as autonomously sustainable
electronics.