Strategies for Optimizing the Morphology of CsSnI3 Perovskite Solar Cells

Abstract

Over the past decade, organic–inorganic hybrid perovskite solar cells (PVSCs) have shown unprecedented growth in power conversion efficiency (PCE) from 3.8% to 25.7%. However, intrinsic thermal instability and lead toxicity are obstacles limiting its large–scale commercialization. Thus, all-inorganic CsSnI3 perovskite has drawn remarkable interest owing to its nontoxicity, excellent thermal stability, low-cost fabrication, and spectacular photoelectric characteristics, including ideal bandgap range, long carrier lifetime, and large absorption coefficient. Many studies have shown that the device performances are closely related to the morphology and crystallinity of perovskite films. In this review, the physical properties of CsSnI3 perovskite are summarized. Furthermore, this review primarily narrates the recent progress in optimizing the morphology by various strategies such as additive engineering, composition regulation, and deposition techniques, emphasizing their effects on grain sizes, film uniformity, grain boundary, and defect passivation.

A Comprehensive Study of CsSnI3-Based Perovskite Solar Cells with Different Hole Transporting Layers and Back Contacts

“…Further experimental findings showed the maximum PCE of 26.1% in 2021 [ 8 , 9 ], and multi-junction perovskite/silicon tandem solar cells achieved a certified PCE of 32.5% [ 10 ]. The cesium tin iodide (CsSnI 3 ) is an eco-friendly inorganic solution for energy harvesting solar cell technology [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Because of the desirable band gap (E g ≈ 1.3 eV) to achieve the ideal Shockley–Queisser theoretical PCE value (highest efficiency of 33.7% at 1.34 eV) than the band gap of lead-based perovskite absorbers (1.5 eV to 2.3 eV), strong visible light absorption coefficient (≈10 4 cm −1 ), effective local hole mobility of ∼400 cm 2 /(V·s) for mitigating the recombination rate, small binding energies of Wannier excitons (~10–20 meV), and easy charge separation, the CsSnI 3 is a more conducive lead-free inorganic perovskite material to achieve the excellent device performance than lead-based hybrid perovskite materials [ 18 , 19 , 20 , 21 ].…”