Photon Upconversion in the Visible Wavelengths with ZnSe/InP/ZnS Nanocrystals
Photon Upconversion in the Visible Wavelengths with ZnSe/InP/ZnS Nanocrystals
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DOI：
10.1021/acs.jpcc.2c07860
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发表时间：
2023-01
期刊：
影响因子：
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通讯作者：
Paulina Jaimes;Tsumugi Miyashita;Tian Qiao;Kefu Wang;M. Tang
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作者：
Paulina Jaimes;Tsumugi Miyashita;Tian Qiao;Kefu Wang;M. Tang
纳米晶体可以强烈吸收近红外（NIR）波长并转换为可见光，这对生物成像应用具有很大的兴趣。在这项工作中，我们研究了一个具有内部InP壳层的逆i型异质结构，用于基于三重态-三重态湮灭的光子上转换。InP基纳米晶体是地球上丰富的，良性的，并且可以在整个近红外窗口中进行合成调谐吸收。在这里，使用两层单层ZnS壳来钝化逆i型ZnSe/InP核/壳粒子的表面缺陷。结果表明，该ZnS壳层将InP光致发光量子产率（QY）提高了16 ~ 0.43倍，发射器三重态寿命从138 μs提高到451 μs，但将三重态能量转移速率降低了3倍。这导致ZnSe/InP和ZnSe/InP/ZnS纳米晶体三重态光敏剂与9,10-二苯基蒽配对作为蓝色发射器时产生相似的约4.0%的光子上转换QY（最大为50%）。这项工作表明，可以进一步调整ZnS壳层以增加光子的上转换QY。这项工作还表明，ZnSe/InP/ZnS纳米晶体是一种有希望的有机-无机混合纳米结构的候选者，可以将近红外光子转换为可见光。
Nanocrystals that can absorb strongly in the near-infrared (NIR) wavelengths for conversion to visible light are of great interest for biological imaging applications. In this work, we examine an inverse Type-I heterostructure with an inner InP shell for triplet–triplet annihilation-based photon upconversion. The InP-based nanocrystals are earth-abundant, benign, and can be synthetically tuned to absorb in the entire NIR window I. Here, a two monolayer ZnS shell was used to passivate the surface defects on inverse Type-I ZnSe/InP core/shell particles. We show that this ZnS shell increases the InP photoluminescence quantum yield (QY) by a factor of 16 to 0.43 and the transmitter triplet lifetime from 138 to 451 μs, but decreases the rate of triplet energy transfer by a factor of 3. This results in the ZnSe/InP and ZnSe/InP/ZnS nanocrystal triplet photosensitizers producing a similar photon upconversion QY of about 4.0% (out of a maximum of 50%) when paired with 9,10-diphenylanthracene as the blue emitter. This work suggests that the ZnS shell can be further tuned to increase the photon upconversion QY. This work also shows that ZnSe/InP/ZnS nanocrystals are promising candidates for a hybrid organic–inorganic nanostructure that can convert NIR photons to visible light.