摘要： Hybrid halide perovskites have become the “next big thing” in emerging semiconductor materials as the past decade witnessed their successful application in high-performance photovoltaics. This resurgence has seen enormous and widespread development of the three-dimensional (3D) perovskites, spearheaded by CH3NH3PbI3. The next generation of halide perovskites, however, is characterized by reduced dimensionality perovskites, emphasizing on the two-dimensional (2D) perovskite derivatives which expand as a more diverse subgroup of semiconducting hybrids that possesses even higher tunability and excellent photophysical properties. In this perspective, we begin with a historical flashback that traces back to early reports before the “perovskite fever” and we follow this original work to its fruition in the present day, where 2D halide perovskites are on the spotlight of current research, thriving on several aspects of high-performance optoelectronics. We approach the evolution of 2D halide perovskites from a structural perspective, providing a classification for the diverse structure-types of the materials, which largely dictate the unusual physical properties observed. We sort out the 2D hybrid halide perovskite based on two key components: the inorganic layers and their modification and the organic cation diversity. As these two heterogeneous components blend, either by synthetic manipulation (shuffling the organic cations or inorganic elements) or by external stimuli (temperature and pressure), the modular perovskite structure evolves to construct crystallographically defined quantum wells (QW). The complex electronic structure that arises is sensitive to the structural features that could be in turn used as a knob to control the dielectric and optical properties the QWs. We conclude this perspective with the most notable optoelectronic device achievements that have been demonstrated to date with an eye towards future material discovery and potential technological developments.