Moreover, lowering the thickness of halide perovskites can improve the binding power of excitons, leading to sturdy amplification of sunshine emission, even at excessive temperatures. Particularly, 2D halide perovskite-based lasers present improved luminescence effectivity, enhanced stability and, due to their layered nature, a variety of chemical versatility. A pioneering work (Y. Liang et al. Adv. Mater. 31, 1903030; 2019) reported multicolour lasing from mechanically exfoliated 2D Pb halide perovskite. Now, Yahui Li et al. (Sci. Adv. 9, eadh0517; 2023) additional exemplify this versatility, reporting 2D Sn halide perovskites, for a greener different to Pb. On this work, the researchers synthesize a collection of extremely phase-pure 2D Sn perovskite bulk crystals and obtain room-temperature lasing with out exterior cavities within the exfoliated flakes.