The critical role of composition-dependent intragrain planar defects in the performance of MA1–xFAxPbI3 perovskite solar cells

Abstract

Perovskite solar cells (PSCs) show excellent power conversion efficiencies, long carrier diffusion lengths and low recombination rates. This encourages a view that intragrain defects are electronically benign with little impact on device performance. Here we vary methylammonium (MA)/ formamidinium (FA) composition in MA1-xFAxPbI3 (x=0-1), and compare the structure and density of intragrain planar defects with the device performance, otherwise keeping the device nominally the same. We find charge carrier lifetime, open-circuit voltage-deficit, and current-voltage hysteresis correlate with the density and structure of {111}c planar defects (x=0.5-1) and {112}t twin boundaries (x=0-0.1). The best performance parameters are found when essentially no intragrain planar defects are evident (x=0.2).Similarly, reducing the density of {111}c planar defects using , also improved performance. These observations suggest that intragrain defect control can provide an important route for improving PSCs' performance, in addition to wellestablished parameters, such as grain boundaries and heterojunction interfaces.

Improved highly efficient Dion–Jacobson type perovskite light-emitting diodes by effective surface polarization architecture

“…The peaks noted by a markers could also be attributed to the a-FAPbI 3 phase, which indicates that the films are mixed phase with multiple components. 27 This is also confirmed by other studies of PDMA-type DJ perovskites. 12,28 Normally, the full-width at half-maximum (FWHM) is an effective parameter with which to investigate the grain size and the crystallinity of the film.…”

Atomically Resolved Electrically Active Intragrain Interfaces in Perovskite Semiconductors

“… 1 , 14 − 18 In this regard, those apparent grain boundaries (GBs) are frequently the only internal interfaces visible in the studies, whereas a considerable density of intragrain interfaces (IGIs) has recently been confirmed to exist in MHPs. 19 Omitting such IGIs potentially causes a misinterpretation of the role of GBs in MHP properties and PSC performance, and this can be one possible cause for the discrepancy in the current understanding of the microstructure–property–performance relationship. Nevertheless, these IGIs do not exhibit noticeable morphological features such as domain boundaries and they are frequently buried underneath the top surfaces, preventing direct observation and characterization using conventional methods.…”

Unveiling the Interaction Mechanisms of Electron and X‐ray Radiation with Halide Perovskite Semiconductors using Scanning Nanoprobe Diffraction

“…Distinctively, degradation does not appear to originate from the twin boundaries, consistent with theoretical predictions, whereby the octahedron face-sharing present at the twin boundary stabilizes the twins. [44,45] Therefore, not all defects affect degradation in the same way.…”