2D Non‐Layered In₂S₃ as Multifunctional Additive for Inverted Organic‐Free Perovskite Solar Cells with Enhanced Performance

Abstract

Organic‐free perovskite solar cells (PSCs) have been of rising interest due to their remarkable resistance toward long‐term thermal stress. Nevertheless, the inorganic perovskite films usually suffer from poor crystallization and high‐density defects in bulk and near/at the interfaces, which leads to significant charge recombination loss and hence inferior device performance. Herein, it is demonstrated that high‐quality CsPbI2Br perovskite films could be prepared by using 2D non‐layered materials as additives, such as In2S3 nanoflakes (Nano‐In2S3) with well‐matched lattices and unsaturated dangling bonds on the surface. In addition, it is found that the introduction of Nano‐In2S3 results in not only defect passivation but also remarkable quasi‐Fermi level splitting across the perovskite film due to its gradient doping behavior, thereby enhancing the built‐in electric field in the inverted PSCs. As a result, the optimal devices based on Nano‐In2S3:CsPbI2Br absorber and all‐inorganic interfacial layers deliver a champion power conversion efficiency of 15.17% along with excellent ambient and thermal stabilities, superior to those of the pristine devices and comparable to the best organic‐free PSCs. A novel strategy for highly efficient and stable organic‐free photovoltaics by using 2D non‐layered materials as multifunctional additives is demonstrated.

Progress and Perspective on Inorganic CsPbI2Br Perovskite Solar Cells

“…In addition to the above-mentioned various molecules that can be used as additives to CsPbI 2 Br perovskite, some nanomaterials are also used as additives. Feng et al [148] successfully obtained 2D nanoflakes In 2 S 3 (Nano-In 2 S 3 ) with a few unit cells by using a simple ball-milling method and applied it as an additive for inverted CsPbI 2 Br PSCs (Figure 10a). Due to the lattice matching and significant chemical interaction between Nano-In 2 S 3 and CsPbI 2 Br perovskite, this additive could tune the crystallization of perovskite.…”

“…Reproduced with permission. [ 148 ] Copyright 2022, Wiley‐VCH. d) Schematic view of the Cr‐MOF‐CsPbI 2 Br heterojunction structure along with in‐plane Cr‐MOF perovskite and CsPbI 2 Br; e) Schematic view of (d) after rotating 90°; f) Reverse and forward scanning J – V curves of the champion pristine CsPbI 2 Br and Cr‐MOF‐CsPbI 2 Br PSCs.…”

“…Figure 10. a) Schematic configuration and b) band alignment of the inverted PSC with Nano-In 2 S 3 ; c) J-V characteristics under 1 sun illumination for the PSCs without and with Nano-In 2 S 3 (0.1-0.3 mg mL −1). Reproduced with permission [148]. Copyright 2022, Wiley-VCH.…”

Preparation of High-Efficiency (>14%) HTL-Free Carbon-Based All-Inorganic Perovskite Solar Cells by Passivation with PABr Derivatives

“…36 38 Tang et al added nano-In 2 S 3 to C S PbI 2 Br, which passivated the defect and enhanced the built-in electric field in inverted PSCs. 39 Yuan et al introduced trace hydrophobic S8 into the C S PbI 2 Br precursor, which not only delayed the crystallization of α-CsPbI 2 Br perovskite but also passivated the grain boundary effectively and improved the photoelectric conversion efficiency. 40 In addition, they creatively introduced bipyrimidine hydroiodide (BP-HI) at the CsPbI 2 Br/ZnO interface, which simultaneously improved the performance of perovskite and electron transport layer (ETL) through a double-side healing strategy.…”

Molecular Interaction Modulates Crystallization and Defects of Perovskite Films for High-Performance Solar Cells

“…Additive engineering has been extensively used to regulate perovskite crystallization and defects passivation. − For example, Liang et al introduced 1,8-diiodooctane (DIO) into perovskite precursor solution to regulate the kinetics of perovskite grains growth through coordinating with Pb 2+ in perovskite during crystallization . Correspondingly, a smoother and more continuous surface of perovskite grains was fabricated compared with that obtained from the pristine solution.…”