sensitivity are the bottlenecks in future commercialization applications. [4,5] Fully-inorganic lead halide perovskites (APbX 3 , A = Cs, Rb, K, etc.), without the organic part affection were expected to resolve the problem of stability. [4,6,7] According to the work of Kubelk et al., fullyinorganic perovskites have similar bandgaps to organo-lead halide analogs and hold much better thermal stability. [4,[7][8][9] Under the scenario of lead-free perovskite, tin (Sn) and germanium (Ge) elements have been considered as hot candidates [10] to replace lead. However, the quick oxidation from Sn 2+ /Ge 2+ to Sn 4+ /Ge 4+ greatly degrades their PCE. [11][12][13] To overcome this problem, heterovalent elements of Sb and Bi were introduced for the implementation of green perovskite. And these perovskite molecular structures transmute from ABX 3 to their derivatives such as A 3 B 2 X 9 .For antimony iodide perovskite (AIP) [14,15] research work, Mitzi and our group combined theoretical calculations, film deposition, and experimental characterizations to understand this new absorber semiconductor. Two kinds of polymorphs exist for Cs 3 Sb 2 I 9 , 0D (dimer) and 2D (layered) phases. Dimer phase exhibits indirect bandgap of 2.50 eV unfavorable for photo voltaics, while layered phase has a direct bandgap of 2.05 eV, a suitable choice as active absorber. The latter one provides similar high level of absorption as CH 3 NH 2 PbI 3 and relatively small in-plane and out-of-plane effective mass. [16][17][18] The layered film could only be synthesized by vapor method with annealing temperature ≈300 °C under the assistance of SbI 3 vapor. [16] Utilizing similar SbI 3 vapor reaction with CsI and SbI 3 precursor film, Chu and co-workers obtained AIP-layered thin film solar cells via a structure of ITO/PEDOT:PSS/AIP/ PC 70 BM/Al and obtained a PCE value of 1.49%. [19] In addition to unique optoelectronic properties, LIP solar cells obtained huge progress highly relying on convenient solution method. The present layered AIP vapor method required high reaction temperature as well as nonuniform composition. Thus, we tried to develop a simple solution method for layered AIP absorbers. According to Zhou and co-workers' theoretical calculations, the AIP dimer phase is an energetically stable Since lead halide perovskite suffers from the obstructions of lead and stability, researchers recently pay more attention to the development of lead-free and stable perovskite absorbers. A typical lead-free antimony iodide perovskite (AIP) is synthesized through vapor reaction at high temperature for photoactive phase. Herein, hydrochloric acid is developed as an intermediate coordinated additive for Cs 3 Sb 2 I 9 photoactive layered phase using HCl-assisted solution method. The uniform and highly crystalline Cs 3 Sb 2 I 9 layered film is obtained by antisolvent engineering. Isopropanol antisolvent is more suitable for present system comparing with traditional lead iodide perovskite-based ones. Physical characterizations manifest the lower trap density, do...

Antimony sulfide (Sb2S3) as a wide‐bandgap, nontoxic, and stable photovoltaic material reveals great potential for the uppermost cells in Si‐based tandem cell stacks. Sb2S3 solar cells with a compatible process, acceptable cost, and high efficiency therefore become the mandatory prerequisites to match silicon bottom cells. The performance of vacuum processed Sb2S3 device is pinned by bulk and interfacial recombination. Herein, a thermally treated TiO2 buffer layer induces quasiepitaxial growth of vertical orientation Sb2S3 absorber overcoming interface defects and absorber transport loss. Such novel growth could pronouncedly improve the open‐circuit voltage (Voc) due to the superior interface quality and intraribbon transport. The epitaxial rough Sb2S3 surface shows a texturized‐like morphology. It is optimized by tuning the grain sizes to form strong light trapping effect, which further enhances the short‐circuit current density (Jsc) with a 16% improvement. The final optimal device with high stability obtains a power conversion efficiency of 5.4%, which is the best efficiency for full‐inorganic Sb2S3 solar cells. The present developed quasiepitaxy strategy supports a superior interface, vertical orientation, and surface light trapping effect, which provides a new perspective for efficient noncubic material thin film solar cells.

Antimony selenide (Sb2Se3) is an ideal photovoltaic candidate profiting from its advantageous material characteristics and superior optoelectronic properties, and has gained considerable development in recent years. However, the further device efficiency breakthrough is largely plagued by severe open‐circuit voltage (VOC) deficit under the existence of multiple defect states and detrimental recombination loss. In this work, an effective absorber layer growth engineering involved with vapor transport deposition and post‐selenization is developed to grow Sb2Se3 thin films. High‐quality Sb2Se3 with large compact crystal grains, benign [hk1] growth orientation, stoichiometric chemical composition, and suitable direct bandgap are successfully fulfilled under an optimized post‐selenization scenario. Planar Sb2Se3 thin‐film solar cells with substrate configuration of Mo/Sb2Se3/CdS/ITO/Ag are constructed. By contrast, such engineering effort can remarkably mitigate the device VOC deficit, owing to the healed detrimental defects, the suppressed interface and space‐charge region recombination, the prolonged carrier lifetime, and the enhanced charge transport. Accordingly, a minimum VOC deficit of 0.647 V contributes to a record VOC of 0.513 V, a champion device with highly interesting efficiency of 7.40% is also comparable to those state‐of‐the‐art Sb2Se3 solar cells, paving a bright avenue to broaden its scope of photovoltaic applications.