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Crystal structure prediction (CSP) of inorganic materials is a fundamental challenge in computational materials science, yet the field has historically lacked well‐defined benchmarks and comprehensive evaluations. We address this gap by introducing CSP180, a standardized benchmark of 180 inorganic materials, and evaluate 13 state‐of‐the‐art CSP algorithms spanning template‐based, machine learning (ML) potential‐based, and deep learning‐based approaches, none relying on density functional theory (DFT). As a baseline, we also assess the leading DFT‐based algorithms, CALYPSO and USPEX, on a 23‐structure subset with simpler compositions. Template‐based methods, such as TCSP and CSPML, achieve the highest space group match rates (58.9% and 47.2%) when a suitable template exists, while de novo algorithms struggle to identify correct space groups, with the best performers reaching only around 17%. On the 23‐structure subset, ML potential‐based algorithms prove highly competitive with DFT‐based methods at identifying lower‐energy structures, and this performance depends strongly on both potential quality and search algorithm efficiency. This assessment provides a standardized framework, quantitative metrics, and open‐source tools to guide future CSP development and accelerate materials discovery. Code and benchmark data are available athttps://github.com/usccolumbia/cspbenchmark. 

Monolayer MoS 2 has long been considered as the most promising candidate for wearable photovoltaic devices. However, its photovoltaic efficiency is restricted by its large band gap (2.0 eV). Though the band gap can be reduced by increasing the number of layers, the indirect band gap nature of the resulting multilayer MoS 2 is unfavorable. Herein, we report a theoretical discovery of the hitherto unknown symmetry-broken phase (denoted as 1T d ) of monolayer MoS 2 through a swarm structure search. The 1T d phase has a distorted octahedral coordinated pattern of Mo, and its direct band gap of 1.27 eV approaches the optimal value of 1.34 eV that gives the Shockley–Queisser limit for photovoltaic efficiency. Importantly, the direct band gap nature persists in thin films with multilayers owing to extremely weak vdW forces between adjacent 1T d layers. The theoretical photovoltaic efficiency at 30 nm thickness reaches ∼33.3%, which is the highest conversion efficiency among all the thin-film solar cell absorbers known thus far. Furthermore, several feasible strategies including appropriate electron injection and annealing methods were proposed to synthesize the 1T d phase. Once synthesized, the superior photovoltaic properties of the 1T d phase may lead to the development of an entirely new line of research for transition metal dichalcogenide solar cells.