Beri Deski, Jakoby Marius, Howard Ian A, Busko Dmitry, Richards Bryce S, Turshatov Andrey
Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
Dalton Trans. 2020 Feb 21;49(7):2290-2299. doi: 10.1039/c9dt04497c. Epub 2020 Feb 4.
Herein, we report a method to produce luminescent silicon nanocrystals (SiNc) that strongly absorb ultraviolet-visible light (300-550 nm) and emit in the near-infrared range (700-1000 nm) with a high photoluminescence quantum yield (PLQY). Using microwave-assisted hydrosilylation and employing reactive chromophores - such as ethenyl perylene, ethynyl perylene and ethylene-m-phenyl BODIPY - we are able to achieve a 10- and 3-fold enhancement of the absorption in the blue and green spectral range, respectively. The investigated dyes function both as passivating agents and highly efficient antenna, which absorb visible light and transfer the energy to SiNc with an efficiency of >95%. This enhanced absorption leads to a significant photoluminescence enhancement, up to ∼270% and ∼140% under excitation with blue and green light, respectively. Despite the gain in absolute brightness of the emission, we demonstrate that back energy transfer from the SiNc to the dyes leads to a decrease in the PLQY for dye-modified SiNc, as compared to unmodified SiNc. The synthesis of the SiNc-dye conjugates opens up new possibilities for applications of this abundant and non-toxic material in the field of solar energy harvesting, optical sensing and bioimaging via achieving strong NIR PL excited with visible light.
在此，我们报告了一种制备发光硅纳米晶体（SiNc）的方法，该纳米晶体强烈吸收紫外-可见光（300-550 nm）并在近红外范围（700-1000 nm）发射，具有高光致发光量子产率（PLQY）。通过微波辅助硅氢化反应并使用反应性发色团，如乙烯基苝、乙炔基苝和乙烯基间苯基BODIPY，我们能够分别在蓝色和绿色光谱范围内将吸收增强10倍和3倍。所研究的染料既作为钝化剂又作为高效天线，吸收可见光并以>95%的效率将能量转移到SiNc。这种增强的吸收导致显著的光致发光增强，在蓝光和绿光激发下分别高达约270%和约140%。尽管发射的绝对亮度有所增加，但我们证明与未修饰的SiNc相比，从SiNc到染料的反向能量转移导致染料修饰的SiNc的PLQY降低。SiNc-染料共轭物的合成通过实现由可见光激发的强近红外PL，为这种丰富且无毒的材料在太阳能收集、光学传感和生物成像领域的应用开辟了新的可能性。
