Energy Transfer from Blue-Emitting CsPbBr3 Perovskite Nanocrystals to Green-Emitting CsPbBr3 Perovskite Nanocrystals
Energy Transfer from Blue-Emitting CsPbBr3 Perovskite Nanocrystals to Green-Emitting CsPbBr3 Perovskite Nanocrystals
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DOI：
10.1021/acs.jpcc.1c05140
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发表时间：
2021-08
期刊：
影响因子：
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通讯作者：
Kazushi Enomoto;Risa Oizumi;Naoya Aizawa;T. Chiba;Yong‐Jin Pu
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作者：
Kazushi Enomoto;Risa Oizumi;Naoya Aizawa;T. Chiba;Yong‐Jin Pu
卤化铯铅（CsPbBr 3）钙钛矿纳米晶在光电领域具有巨大的应用潜力。然而，由于浓度猝灭，它们在膜状态下的光致发光量子产率（PLQY）低于在溶液状态下的光致发光量子产率;因此，PLQY在发光器件应用中是一个问题。在这里，我们证明了能量供体-受体系统的CsPbBr 3 NCs，由相同的卤素组成，但具有不同的尺寸，实现有效的抑制浓度猝灭和高的光学稳定性。CsPbBr 3 NCs的能带隙取决于它们的尺寸，由于量子限制效应，并表现为量子点（QD）。与较小的蓝色发射CsPbBr 3QD（BPeQD）混合的绿色发射CsPbBr 3QD（GPeQD）膜的PLQY比纯膜的PLQY高约2倍（20%）。PL，光致发光激发（PLE），和瞬态PL（TRPL）光谱表明，这种改善PLQY在膜状态的根源在FRET从BPeQD到GPeQD，导致有效抑制浓度猝灭。该能量供体-受体系统中的发射颜色在溶液和膜状态下是稳定的，尽管由于卤素交换反应和所产生的发射颜色变化，这不能通过具有不同卤素的铯铅卤化物NC实现。
Cesium lead halide (CsPbBr3) perovskite nanocrystals (NCs) have great potential for optoelectronic applications. However, their photoluminescence quantum yield (PLQY) in the film state is lower than that in the solution state due to concentration quenching; thus, PLQY is an issue in light-emitting device applications. Here, we demonstrate that energy donor–acceptor systems of CsPbBr3NCs, composed of the same halogen composition but with different sizes, realize efficient suppression of concentration quenching and high optical stability. The energy band gap of CsPbBr3NCs depends on their size due to the quantum confinement effect and behaves as quantum dots (QDs). The PLQY of a green-emitting CsPbBr3QD (GPeQD) film mixed with smaller blue-emitting CsPbBr3QDs (BPeQDs) was approximately 2 times higher than that of the neat film (20%). PL, photoluminescence excitation (PLE), and transient PL (TRPL) spectroscopies revealed that this improvement of PLQY in the film state has roots in FRET from BPeQD to GPeQD, resulting in efficient suppression of concentration quenching. The emission color in this energy donor–acceptor system was stable in the solution and film states, although this could not be achieved by cesium lead halide NCs with different halogens due to the halogen exchange reaction and resulting emission color change.