Photoluminescence tunability is exceedingly crucial to all-inorganic halide perovskite (CsPbX₃, X = Cl, Br, I) quantum dots (QDs) for high-resolution display. However, up to now, the wide-range color tunability could only be achieved by varying the halide ratio. A drawback in this approach is the color instability caused by inevitable halide ion exchange. Therefore, it is of great significance to exploit the new train of thought to tune the emission color in a wide range. Herein, we designed a novel exciton energy-transfer strategy by introducing the ¹G₄ energy level of Tm to construct the intermediate gradient energy levels between the conduction band of the host perovskite and the ⁴T₁ energy level of Mn for efficiently promoting the exciton energy transfer from the host perovskite to Mn. Thus, the emission color could be accurately tuned from green to orange, and the corresponding correlated color temperature changed from 12 400 to 1800 K. Most strikingly, the single-component pure white light QDs with a record photoluminescence quantum yield (PLQY) of 54% were obtained based on this strategy. Additionally, white light-emitting diodes with a color rendering index up to 91 and a CIE color coordinate of (0.33, 0.34) are further fabricated. Therefore, we believe that this novel exciton energy-transfer strategy will possibly open up a new avenue for efficient emission controllability of all-inorganic perovskites, promoting the higher PLQY of single-component white light QDs and facilitating practical application.

中文翻译：

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构建梯度能级以促进激子能量转移以实现全无机钙钛矿的光致发光可控性及其在单组分WLED中的应用

对于高分辨率显示而言，光致发光可调性对于全无机卤化物钙钛矿（CsPbX ₃，X = Cl，Br，I）量子点（QDs）至关重要。但是，到目前为止，只有通过改变卤化物比率才能实现宽范围的颜色可调性。该方法的缺点是由不可避免的卤化物离子交换引起的颜色不稳定性。因此，利用新的思路在大范围内调整发射颜色具有重要意义。本文中，我们通过引入Tm的¹ G ₄能级来构造主体钙钛矿的导带和⁴ T ₁之间的中间梯度能级，从而设计了一种新颖的激子能量转移策略。Mn的能级，以有效地促进激子能量从主体钙钛矿传递到Mn。因此，可以将发射颜色从绿色准确地调整为橙色，并且相应的相关色温从12400变为1800K。最引人注目的是，单组分纯白光QD的记录的光致发光量子产率（PLQY）为54 ％是基于该策略获得的。另外，还制造了显色指数高达91且CIE色坐标为（0.33，0.34）的白色发光二极管。因此，我们相信这种新颖的激子能量转移策略将为全无机钙钛矿的有效排放控制开辟一条新途径，促进单组分白光量子点的较高PLQY，并为实际应用提供便利。