Crystallographically Oriented Hybrid Perovskites via Thermal Vacuum Codeposition

Abstract

Hybrid lead halide perovskites typically form polycrystalline films that have multiple grain sizes and surface defects. A key engineering challenge toward commercialization is therefore the production of homogeneous, defect‐free large‐area devices achieving high efficiency. New market opportunities may arise from vacuum‐deposited perovskites if detailed understanding and control of crystal formation are available. Of the many factors that make reproducibility of device performance difficult, two variables are identified that have not yet been considered in detail: deposition speed and underlayer material selection. Herein, it is demonstrated that small changes in the perovskite growth rate (0.18–0.72 Å·s−1) substantially affect the preferred crystal orientation. Further, varying underlayer interfaces greatly influence the composition of the final perovskite and thus its energetic profile. The research aids control in fine‐tuning the perovskite film at the nanometer scale, which enables the reproducible fabrication of vertically aligned and micrometer‐sized grain features, highly demanded for in high‐quality semiconductors.

Face-on oriented hydrophobic conjugated polymers as dopant-free hole-transport materials for efficient and stable perovskite solar cells with a fill factor approaching 85%

“…To obtain a more in-depth insight into the molecular stacking of PBZ-Si polymers, the angular dependence of the diffraction peak at q z ∼1.75 Å −1 was examined. 68 The intensity of the peak became significantly higher at ∼80° for the sample of ITO/SnO 2 /perovskite/PBZ-3Si (Fig. S7b†), indicating a similarly well-aligned PBZ-3Si polymer to the sample of Si/PBZ-3Si (Fig.…”

Structural and photophysical investigation of single-source evaporation of CsFAPbI3 and FAPbI3 perovskite thin films

“…We have described a positive effect MeO-groups on the perovskite crystallization, leading to micrometer-sized crystal features. [37] nm than the grains on MoO3/Spiro-OMeTAD (~333 nm). On SnO2 and MeO-2PACz, the perovskite grains showed a larger average size (~455nm and ~404nm) and can be easily distinguished by their grain-like features.…”

“…reported that the chemical groups of underlayer influence the perovskite formation and stability, [37] we, therefore, investigated the formation of the perovskite layer on different organic materials. We extended our study to the state-of-the-art used underlayers.…”

“…Spiro-OMeTAD methoxy-groups, MeO-2PACz phosphonic acid groups, and the inorganic oxide SnO2, to have one reference that is not an organic one. TaTm [38] , Spiro-OMeTAD [37] ,…”

“…Oxides were significantly hindered due to their catalytic nature, promoting only after 100 nm precursor deposition perovskite growth. [37] In the case of the underlayer SnO2, large holes can be observed independently of the perovskite deposited. Similar large holes are observed for the α-CsFAPbI3 and α-FAPbI3 films with the underlayer of MeO-2PACs.…”