Visible to Near-Infrared Sensitization of Silicon Substrates via Energy Transfer from Proximal Nanocrystals: Further Insights for Hybrid Photovoltaics
Visible to Near-Infrared Sensitization of Silicon Substrates via Energy Transfer from Proximal Nanocrystals: Further Insights for Hybrid Photovoltaics
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DOI：
10.1021/nn400924y
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发表时间：
2013-04-01
期刊：
影响因子：
17.1
通讯作者：
Malko, Anton V.
中科院分区：
文献类型：
--
作者：
Nimmo, Michael T.;Caillard, Louis M.;Malko, Anton V.
我们提供了一个统一的光谱证据，有效的能量转移（EL）从光激发的胶体纳米量子点（NQD）到硅基板在很宽的波长范围内：从可见光（545 nm）到近红外（800 nm）。通过胺改性的羧基烷基链连接体实现纳米晶体在氢化Si表面上的化学接枝，从而确保完全的表面钝化和精确的NQD定位。测量了一组不同尺寸和成分的CdSe/ZnS和CdSeTe/ZnS纳米量子点在Si和SiO2衬底上的光致发光（PL）。基于Si和NQD Si分离距离的频率依赖性介电性质，测量的Si衬底上PL衰减的加速与理论预期吻合得很好。比较分析揭示了来自非辐射（NRET）和辐射（NRET）通道的对Er的单独贡献：NRET是可见光范围中间的近端NQD的主导机制，并与RET对近红外波长相当。ET效率估计为9056的水平的宽范围进一步支持了混合纳米晶/硅薄膜光伏器件可以在整个波长光谱上有效地收集太阳能的概念。
We provide a unified spectroscopic evidence of efficient energy transfer (El) from optically excited colloidal nanoaystal quantum dots (NQDs) into Si substrates in a broad range of wavelengths: from visible (545 nm) to near-infrared (800 nm). Chemical grafting of nanocrystals on hydrogenated Si surfaces is achieved via amine-modified carboxyal alkyl chain linkers, thus ensuring complete surface passivation and accurate NQD positioning. lime-resolved photoluminescence (PL) has been measured for a set of CdSe/ZnS and CdSeTe/ZnS NQDs of various sizes and compositions grafted on Si and SiO2 substrates. The measured acceleration of the PL decays on Si substrates is in good agreement with theoretical expectations based on the frequency-dependent dielechic properties of Si and NQD Si separation distances. A comparative analysis reveals separate contributions to Er coming from the nonradiative (NRET) and radiative (NRET) channels: NRET is a dominant mechanism for proximal NQDs in the middle of the visible range and becomes comparable with RET toward near-infrared wavelengths. The broad range over which the ET efficiency is estimated to be at the level of 9056 further supports the concept that hybrid nanoaystal/ silicon thin-film photovoltaic devices could efficiently harvest solar energy across the entire spectrum of wavelengths.