Sputtering Mechanism of an Unsintered Organic-Inorganic Sputtering Target for Perovskite Solar Cells

초록

Vacuum-based deposition of hybrid organic-inorganic perovskites (HOIPs) remains a critical yet unresolved challenge for enabling scalable, solvent-free manufacturing of perovskite optoelectronics. Here, tetragonal methylammonium lead iodide (beta-MAPbI3) single-phase crystals with high structural uniformity are synthesized via an antisolvent vapor-assisted crystallization process and utilized as feedstock for a 3-inch unsintered MAPbI3 sputtering target fabricated through mechanochemical processing and low-temperature consolidation. The resulting target exhibits sufficient compactness and mechanical integrity to sustain RF magnetron sputtering without macroscopic fracture while retaining its beta-phase crystallographic signature under plasma exposure. However, sputtered films derived from this target consistently exhibit PbI2-dominant characteristics. Correlative analysis of target surface evolution and film composition indicates a progressive loss of organic and iodine species during sputtering, leading to a compositionally altered sputtered flux. Such behavior can be reasonably attributed to the combined effects of energetic ion bombardment and photon irradiation intrinsic to RF plasma environments. Consequently, direct sputter deposition does not readily preserve MAPbI3 stoichiometry, even when high-quality single-phase crystal-derived targets are employed, suggesting that post-deposition reconstruction strategies may be required to restore the perovskite phase. This work provides fundamental insights into plasma-perovskite interactions and establishes a foundation for sputtering-based routes toward scalable perovskite photoabsorber fabrication.

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