Photoluminescence Temperature Dependence, Dynamics, and Quantum Efficiencies in Mn2+-Doped CsPbCl3 Perovskite Nanocrystals with Varied Dopant Concentration,Chemistry of Materials

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Photoluminescence Temperature Dependence, Dynamics, and Quantum Efficiencies in Mn2+-Doped CsPbCl3 Perovskite Nanocrystals with Varied Dopant Concentration
Chemistry of Materials ( IF 7.2 ) Pub Date : 2017-09-07 00:00:00 , DOI: 10.1021/acs.chemmater.7b03311
Xi Yuan ₁ , Sihang Ji ₁ , Michael C. De Siena ₂ , Liling Fei ₁ , Zhao Zhao _{1,

3} , Yunjun Wang ₄ , Haibo Li ₁ , Jialong Zhao _{1,

3} , Daniel R. Gamelin ₂

Affiliation

A series of Mn²⁺-doped CsPbCl₃ nanocrystals (NCs) was synthesized using reaction temperature and precursor concentration to tune Mn²⁺ concentrations up to 14%, and then studied using variable-temperature photoluminescence (PL) spectroscopy. All doped NCs show Mn²⁺ ⁴T_1g → ⁶A_1g d–d luminescence within the optical gap coexisting with excitonic luminescence at the NC absorption edge. Room-temperature Mn²⁺ PL quantum yields increase with increased doping, reaching ∼60% at ∼3 ± 1% Mn²⁺ before decreasing at higher concentrations. The low-doping regime is characterized by single-exponential PL decay with a concentration-independent lifetime of 1.8 ms, reflecting efficient luminescence of isolated Mn²⁺. At elevated doping, the decay is shorter, multiexponential, and concentration-dependent, reflecting the introduction of Mn²⁺–Mn²⁺ dimers and energy migration to traps. A large, anomalous decrease in Mn²⁺ PL intensity is observed with decreasing temperature, stemming from the strongly temperature-dependent exciton lifetime and slow exciton-to-Mn²⁺ energy transfer, which combine to give a strongly temperature-dependent branching ratio for Mn²⁺ sensitization.

中文翻译：

掺杂浓度不同的Mn ²⁺掺杂CsPbCl ₃钙钛矿纳米晶体中的光致发光温度依赖性，动力学和量子效率。

使用反应温度和前驱体浓度合成了一系列Mn ²⁺掺杂的CsPbCl ₃纳米晶体（NCs），以将Mn ²⁺浓度调节至14％，然后使用变温光致发光（PL）光谱进行了研究。所有掺杂的NC均在光学间隙内显示Mn ²⁺ ⁴ T _1g → ⁶ A _1g d–d发光，并与NC吸收边缘处的激子发光共存。室温Mn ²⁺ PL量子产率随着掺杂的增加而增加，在Mn ^3+约3±1％时达到约60％然后在较高浓度下降低。低掺杂状态的特征是单指数PL衰变，其浓度无关的寿命为1.8 ms，反映了隔离的Mn ^2+的有效发光。在高掺杂下，衰变更短，呈指数级增长且与浓度有关，这反映了Mn ²⁺ -Mn ²⁺二聚体的引入以及能量向陷阱的迁移。观察到随着温度降低，Mn ²⁺ PL强度出现异常的大幅度下降，这是由于强烈的温度依赖性激子寿命和缓慢的激子向Mn ²⁺能量转移^所致，两者结合在一起就产生了强烈的温度依赖性分支比。 Mn ²⁺敏化。

更新日期：2017-09-07

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