This study determined the effect of introducing the NH4SCN additive in the precursor solution of PbI2 of a sequential deposition method in an open atmosphere to form FAPbI3 perovskite over… Click to show full abstract
This study determined the effect of introducing the NH4SCN additive in the precursor solution of PbI2 of a sequential deposition method in an open atmosphere to form FAPbI3 perovskite over a glass substrate. Adding NH4SCN leads to different intermediate layers according to the concentration of the additive. From an adequate concentration, an ionic substitution between I− and SCN− is promoted, providing a unique path for nucleation and growth of FAPbI3 due to significant changes in morphology. The intermediate layer with a proper amount of NH4SCN enhanced the physical properties of FAPbI3. It contributed to understanding the crystallinity and morphological conditions for favorable growth of FAPbI3 directly over a glass substrate. A concentration of 40% gave rise to the biggest grain size, homogeneous morphology, higher absorption, and prevalence of black phase in the α/δ phase coexistence. As a result, the perovskite with the NH4SCN additive showed a positive effect on the growth mechanisms and enhanced stability due to the mixed α/δ-phase and grain size ∼1350 nm. The preceding makes FAPbI3 film with a concentration of 40% a good option for application as stable perovskite in solar cells.
               
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