Living growth of ultra-bright 2D perovskites with long-lived carriers

Growth-induced defects and strain in two-dimensional (2D) perovskites severely limit carrier transport and suppress radiative efficiency, thereby sacrificing the carrier lifetime and obscuring the advantages from quantum confinement. Here, we report a near-equilibrium isothermal (NEIT) growth paradigm of 2D perovskite single crystals that exhibits living growth characteristics analogous to living polymerization. This approach confines crystallization primarily to initial nuclei, resulting in ultra-low nucleation density and yielding centimeter-scale single crystals of PEA₂PbI₄ (Pb-n1), PEA₂MAPb₂I₇ (Pb-n2), and PEA₂MA₂Pb₃I₁₀ (Pb-n3) with enhanced crystallographic perfection. This process achieves ~89% utilization of Pb precursor for Pb-n1, significantly surpassing ~13% from conventional methods and aligning with green-chemistry and sustainable synthetic principles. Additionally, the trap density gets suppressed by one order of magnitude. This unlocks high photoluminescence quantum yields (PLQYs, 77 ± 2% for Pb-n1), first cavity-free lasing in 2D Pb-n1 perovskite flakes, and long carrier lifetimes with diffusion lengths up to ~1.92 μm rivaling 3D perovskites. Critically, the living NEIT growth successfully enables the epitaxy of 2D bulk perovskite heterostructures, driving 60-fold accelerated photocarrier separation in lateral photodetectors. This near-equilibrium living growth paradigm establishes defect-minimized 2D perovskites as a versatile and active platform for high-performance quantum-well optoelectronics.