Energy Research Institute at NTU (ERI@N) , Research Techno Plaza, X-Frontier Block Level 5, 50 Nanyang Drive, Singapore 637553.
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371.
Nano Lett. 2017 Dec 13;17(12):7424-7432. doi: 10.1021/acs.nanolett.7b03272. Epub 2017 Nov 14.
We report the high yield synthesis of about 11 nm sized CHNHPbBr nanocrystals with near-unity photoluminescence quantum yield. The nanocrystals are formed in the presence of surface-binding ligands through their direct precipitation in a benzyl alcohol/toluene phase. The benzyl alcohol plays a pivotal role in steering the surface ligands binding motifs on the NC surface, resulting in enhanced surface-trap passivation and near-unity PLQY values. We further demonstrate that thin films from purified CHNHPbBr nanocrystals are stable >4 months in air, exhibit high optical gain (about 520 cm), and display stable, ultralow amplified spontaneous emission thresholds of 13.9 ± 1.3 and 569.7 ± 6 μJ cm at one-photon (400 nm) and two-photon (800 nm) absorption, respectively. To the best of our knowledge, the latter signifies a 5-fold reduction of the lowest reported threshold value for halide perovskite nanocrystals to date, which makes them ideal candidates for light-emitting and low-threshold lasing applications.
我们报告了一种高产率的合成方法，可得到约 11nm 尺寸的 CHNHPbBr 纳米晶，其光致发光量子产率接近 1。这些纳米晶是在表面结合配体的存在下，通过直接在苄醇/甲苯相中沉淀形成的。苄醇在控制 NC 表面上的表面配体结合模式方面起着关键作用，从而增强了表面陷阱钝化和接近 1 的 PLQY 值。我们进一步证明，从纯化的 CHNHPbBr 纳米晶制备的薄膜在空气中稳定>4 个月，表现出高光学增益（约 520cm），并显示出稳定的超低放大自发发射阈值，分别为 13.9±1.3 和 569.7±6μJcm 在单光子（400nm）和双光子（800nm）吸收时。据我们所知，这是迄今为止卤化物钙钛矿纳米晶报告的最低阈值值降低了 5 倍，这使得它们成为发光和低阈值激光应用的理想候选材料。
