Validated Analysis of Component Distribution Inside Perovskite Solar Cells and Its Utility in Unveiling Factors of Device Performance and Degradation

Abstract

Time-of-flight secondary-ion mass spectrometry (ToF-SIMS) has been used for gaining insights into perovskite solar cells (PSCs). However, the importance of selecting ion beam parameters to eliminate artifacts in the resulting depth profile is often overlooked. In this work, significant artifacts were identified with commonly applied sputter sources, i.e., an O 2 + beam and an Ar-gas cluster ion beam (Ar-GCIB), which could lead to misinterpretation of the PSC structure. On the other hand, polyatomic C 60 + and Ar + ion beams were found to be able to produce depth profiles that properly reflect the distribution of the components. On the basis of this validated method, differences in component distribution, depending on the fabrication processes, were identified and discussed. The solvent-engineering process yielded a homogeneous film with higher device performance, but sequential deposition led to a perovskite layer sandwiched by methylammonium-deficient layers that impeded the performance. For device degradation, it was found that most components remained intact at their original position except for iodide. This result unambiguously indicated that iodide diffusion was one of the key factors governing the device lifetime. With the validated parameters provided, ToF-SIMS was demonstrated as a powerful tool to unveil the structure variation amid device performance and during degradation, which are crucial for the future development of PSCs.

Acetamidinium Cation to Confer Ion Immobilization and Structure Stabilization of Organometal Halide Perovskite Toward Long Life and High‐Efficiency p‐i‐n Planar Solar Cell via Air‐Processable Method

“…The I–V characteristics of devices were analyzed from both forward −0.2 to 1.2 V) and backward (1.2 to −0.2 V) scans. The analysis protocol of ToF‐SIMS followed by the previous study . Briefly, the gradient of test voltage was fixed at 50 mV or −50 mV with a delay span of 10 ms. All the ToF‐SIMS depth profiles were obtained using a PHI TRIFT V nano TOF (ULVAC‐PHI, Japan) system with a dual‐beam sputter‐and‐view scheme.…”

Probing Surface Information of Alloy by Time of Flight-Secondary Ion Mass Spectrometer

“…It is worth mentioning here that selecting proper ion-beam parameters to conduct the measurements is necessary and important. Both the primary and sputtering ion beams could influence the acquired data [30][31][32] by varying their damage depth, cluster sizes, sputtering rate, etc. For instance, C 60 + and Ar + ion beams could reveal the component distribution of perovskite solar cells more accurately than O 2 + beam and Ar-gas cluster ion beam [31] (Ar-GCIB).…”

Ambient Manipulation of Perovskites by Alternating Electric Field toward Tunable Photovoltaic Performance

“…[24,52] Noticeably, certain artifact of MA signal [53] can be observed in the region near the perovskite/ITO interface that could be induced by MA oxidation by O 2 + sputtering, as has also been reported by some recent studies. [54] However, this will not influence the overall result that the general redistribution of MA + ions is toward perovskite/ITO interface since all measurements have been performed on samples with identical thickness and contents.…”