Absolute photoluminescence quantum yields of IR26 and IR-emissive Cd1-xHgxTe and PbS quantum dots - method- and material-inherent challenges
Absolute photoluminescence quantum yields of IR26 and IR-emissive Cd1-xHgxTe and PbS quantum dots - method- and material-inherent challenges
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DOI：
10.1039/c4nr04608k
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发表时间：
2015-01-01
期刊：
影响因子：
6.7
通讯作者：
Resch-Genger, Ute
中科院分区：
文献类型：
--
作者：
Hatami, Soheil;Wuerth, Christian;Resch-Genger, Ute
在 800-1600 nm 光谱范围内具有光致发光的明亮发射体作为分子成像、传感和电信的光学报道分子以及电光和光伏器件中的有源元件越来越重要。它们的合理设计与表征其信号相关特性的合适方法直接相关，特别是其光致发光量子产率 (Phi(f))。针对发射>1000 nm的明亮半导体纳米晶体的发展，我们设计了一种适用于600-1600 nm波长范围的新型近红外/红外积分球装置。我们通过获取有机染料 Itrybe、IR140 和 IR26 以及几种红外 (IR) 发射 Cd1-xHgxTe 和 PbS 半导体纳米晶体的校正发射光谱和 Phi(f) 来评估该装置的性能，并将它们与使用两个独立校准的荧光仪器获得的数据绝对或相对于先前评估的参考染料进行比较。我们的结果强调了红外光致发光研究的特殊挑战，从溶剂吸收到缺乏光谱和强度标准，以及量子点特定的挑战，如光增白和光暗化，以及不同尺寸的油酸盐封端的 PbS 胶体的尺寸依赖性空气稳定性和光稳定性。这些效应可以代表铅硫属化物。此外，我们通过彻底的样品重吸收和溶剂吸收校正，将最常用的红外参考染料 IR26 在 1,2-二氯乙烷 DCE 中的 Phi(f) 重新测定为 1.1 x 10(-3)。我们的结果表明需要对红外发射纳米材料的 Phi(f) 值进行严格的重新评估，并为改进 Phi(f) 测量提供指导。
Bright emitters with photoluminescence in the spectral region of 800-1600 nm are increasingly important as optical reporters for molecular imaging, sensing, and telecommunication and as active components in electrooptical and photovoltaic devices. Their rational design is directly linked to suitable methods for the characterization of their signal-relevant properties, especially their photoluminescence quantum yield (Phi(f)). Aiming at the development of bright semiconductor nanocrystals with emission >1000 nm, we designed a new NIR/IR integrating sphere setup for the wavelength region of 600-1600 nm. We assessed the performance of this setup by acquiring the corrected emission spectra and Phi(f) of the organic dyes Itrybe, IR140, and IR26 and several infrared (IR)-emissive Cd1-xHgxTe and PbS semiconductor nanocrystals and comparing them to data obtained with two independently calibrated fluorescence instruments absolutely or relative to previously evaluated reference dyes. Our results highlight special challenges of photoluminescence studies in the IR ranging from solvent absorption to the lack of spectral and intensity standards together with quantum dot-specific challenges like photobrightening and photodarkening and the size-dependent air stability and photostability of differently sized oleate-capped PbS colloids. These effects can be representative of lead chalcogenides. Moreover, we redetermined the Phi(f) of IR26, the most frequently used IR reference dye, to 1.1 x 10(-3) in 1,2-dichloroethane DCE with a thorough sample reabsorption and solvent absorption correction. Our results indicate the need for a critical reevaluation of Phi(f) values of IR-emissive nanomaterials and offer guidelines for improved Phi(f) measurements.