Temperature‐Reliable Low‐Dimensional Perovskites Passivated Black‐Phase CsPbI₃ toward Stable and Efficient Photovoltaics

Abstract

Low‐dimensional (LD) perovskites can effectively passivate and stabilize 3D perovskites for high‐performance perovskite solar cells (PSCs). Regards CsPbI3‐based PSCs, the influence of high‐temperature annealing on the LD perovskite passivation effect has to be taken into account due to fact the black‐phase CsPbI3 crystallization requires high‐temperature treatment, however, which has been rarely concerned so far. Here, the thermal stability of LD perovskites based on three hydrophobic organic ammonium salts and their passivation effect toward CsPbI3 and the whole device performance, have been investigated. It is found that, phenyltrimethylammonium iodide (PTAI) and its corresponding LD perovskites exhibit excellent thermal stability. Further investigation reveals that PTAI‐based LD perovskites are mainly distributed at grain boundaries, which not only enhances the phase stability of CsPbI3 but also effectively suppresses non‐radiative recombination. As a consequence, the champion PSC device based on CsPbI3 exhibits a record efficiency of 21.0 % with high stability.

Solvent Engineering for High-Performance Two-Dimensional Ruddlesden–Popper CsPbI3 Solar Cells

“…Cesium lead halide perovskites without volatile organic compositions, whose general chemical formula is CsPbX 3 (X is halides or their mixture), have attracted wide attention due to excellent thermal stability and high formation energy. − Among them, CsPbI 3 with a desirable band gap (<1.73 eV) and good stability shows great potential in the photovoltaic field. − So far, the power conversion efficiency (PCE) of CsPbI 3 -based perovskite solar cells (PSCs) improved to 21.0% from the first reported 2.9% in 2015. , However, the poor phase stability is a huge obstacle to further commercial application . Desirable photoactive black-phase perovskite (γ-CsPbI 3 ) can spontaneously transform to undesirable yellow-phase nonperovskite (δ-CsPbI 3 ) caused by a low limit of tolerance factor of 0.81 (0.8 < τ < 1.0) at room temperature (RT). , Many strategies have been used to enhance the phase stability of black-phase CsPbI 3 perovskite, for example, ionic incorporation, organic cation surface termination, reduced dimensions (quantum dot, quasi two-dimensional (2D)), and so on. − Among these strategies, 2D or quasi-2D CsPbI 3 is an extremely effective and promising one.…”

“…6−9 So far, the power conversion efficiency (PCE) of CsPbI 3 -based perovskite solar cells (PSCs) improved to 21.0% from the first reported 2.9% in 2015. 10,11 However, the poor phase stability is a huge obstacle to further commercial application. 12 Desirable photoactive black-phase perovskite (γ-CsPbI 3 ) can spontaneously transform to undesirable yellowphase nonperovskite (δ-CsPbI 3 ) caused by a low limit of tolerance factor of 0.81 (0.8 < τ < 1.0) at room temperature (RT).…”

Efficient and Stable Mesoporous CsSnI3 Perovskite Solar Cells via Imidazolium‐Based Ionic Liquid Additive

“…[ 10–12 ] However, compared with all‐inorganic lead halide PSCs where PCE has jumped substantially over 20%, the potential applications of fully inorganic CsSnI 3 PSCs are severely suffered from the limitation of a low PCE, mainly on output photovoltage. [ 13,14 ]…”

“…[10][11][12] However, compared with all-inorganic lead halide PSCs where PCE has jumped substantially over 20%, the potential applications of fully inorganic CsSnI 3 PSCs are severely suffered from the limitation of a low PCE, mainly on output photovoltage. [13,14] Sn 2þ -induced defects are a major obstacle for the realization of efficient Sn-based PSCs. [15] The defect types are mainly divided into internal Sn vacancy defects and surface undercoordinated Sn 2þ cations defects.…”

Crystallization and Defect Chemistry Dual Engineering for MAPbI3 Perovskite Solar Cells with Efficiency Approaching 22%

“…Each sub-cell efficiency reached 22%, − while the tandem cell efficiency reached 28% . The cesium-based all-inorganic component was employed to avoid thermal degradation, and its efficiency reached 21%, etc . As the earliest developed perovskite absorber, methylammonium lead triiodide (MAPI) was intensively explored to advance efficiencies in the early times and is now widely used as a case study to make inferences about other, more complex perovskite compositions.…”