The outstanding excitonic properties, including photoluminescence quantum yield (η_PL), of individual, quantum-confined semiconductor nanoparticles are often significantly quenched upon aggregation, representing the main obstacle toward scalable photonic devices. We report aggregation-induced emission phenomena in lamellar solids containing layer-controlled colloidal quantum wells (QWs) of hybrid organic-inorganic lead bromide perovskites, resulting in anomalously high solid-state η_PL of up to 94%. Upon forming the QW solids, we observe an inverse correlation between exciton lifetime and η_PL, distinct from that in typical quantum dot solid systems. Our multiscale theoretical analysis reveals that, in a lamellar solid, the collective motion of the surface organic cations is more restricted to orient along the [100] direction, thereby inducing a more direct bandgap that facilitates radiative recombination. Using the QW solids, we demonstrate ultrapure green emission by completely downconverting a blue gallium nitride light-emitting diode at room temperature, with a luminous efficacy higher than 90 lumen W^-1 at 5000 cd m^-2, which has never been reached in any nanomaterial assemblies by far.

中文翻译：

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聚集体在胶态钙钛矿量子阱层状固体中的发射。

优秀的激子的性能，包括光致发光量子产率（η _PL），个人，量子约束半导体纳米颗粒通常显著在聚合淬灭，表示朝向可扩展光子器件的主要障碍。我们报告在层状固体含有层控制的胶体量子阱（量子阱）杂化有机-无机溴化铅钙钛矿的聚集诱导的发射现象，从而导致异常高的固态η _PL达到94％。在形成固体QW，我们观察激子寿命和η之间的逆相关_PL，不同于典型的量子点固体系统。我们的多尺度理论分析表明，在层状固体中，表面有机阳离子的集体运动受到更大限制，使其沿着[100]方向取向，从而产生了更直接的带隙，从而有利于辐射复合。使用QW固体，我们通过在室温下完全下变频蓝色氮化镓发光二极管来证明超纯绿色发射，在5000 cd m ^-2时的发光效率高于90流明W ^-1，这在任何情况下都没有达到。纳米材料组装。