Photonic band engineering in absorbing media for spectrally selective optoelectronic films.
Photonic band engineering in absorbing media for spectrally selective optoelectronic films.
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光谱选择性光电薄膜吸收介质中的光子带工程。
DOI：
10.1364/oe.26.026933
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发表时间：
2018
期刊：
影响因子：
3.8
通讯作者：
S. Thon
中科院分区：
文献类型：
--
作者：
Botong Qiu;Yida Lin;Ebuka S. Arinze;Arlene Chiu;Lulin Li;S. Thon
光谱选择性材料是光电子器件的研究热点，在多结太阳能电池、窄带光电探测器、透明光伏和定制发射源等应用中，光活性材料的波长选择性是必不可少的。在吸收、反射和透射谱的多个波长范围内实现可控的透明度或不透明度在传统半导体中是很难实现的，因为传统半导体通常在其电子带隙以上吸收所有能量，并且通常通过使用外部带通滤波器来实现。在这里，我们提出了一种在光电薄膜中实现光谱选择性的替代方法：在半导体的吸收区域内使用光子能带工程，其中共振光子带与外部反射率和透射率光谱强烈耦合。作为第一步，我们利用光学模拟系统地研究了材料吸收对光子晶体平板结构中光子带性质的影响。我们发现，在材料模型中加入弱损耗并不会显著改变光子带的频率，但会降低相关光子模的品质因数。最重要的是，由于辐射光子带与外部电磁平面波之间的耦合，即使在存在物质吸收的情况下，辐射光子带也会在透射谱和反射谱中产生强烈的Fano共振特征。这些共振可以通过调整光子晶体的结构属性来调节，以在半导体的吸收区域诱导光谱选择性。最后，我们通过实验验证了这种调谐方法，该结构由自组装的聚苯乙烯微珠单层组成，渗透了PbS量子点，在均匀的控制薄膜上表现出近红外吸收增强和可见光透明增强，定性地与预测相匹配，展示了光电子学应用的前景。
Spectrally selective materials are of great interest for optoelectronic devices in which wavelength-selectivity of the photoactive material is necessary for applications such as multi-junction solar cells, narrow-band photodetectors, transparent photovoltaics, and tailored emission sources. Achieving controlled transparency or opacity within multiple wavelength bands in the absorption, reflection, and transmission spectra are difficult to achieve in traditional semiconductors that typically absorb at all energies above their electronic band gap and is generally realized by the use of external bandpass filters. Here, we propose an alternate method for achieving spectral selectivity in optoelectronic thin films: the use of photonic band engineering within the absorbing region of a semiconductor in which resonant photonic bands are strongly coupled to the external reflectivity and transmission spectra. As a first step, we use optical simulations to systematically study the effect of material absorption on the properties of the photonic bands in a photonic crystal slab structure. We find that adding a weak loss to the materials model does not appreciably change the frequencies of the photonic bands but does reduce the quality factor of the associated photonic modes. Critically, the radiating photonic bands induce strong Fano resonance features in the transmission and reflection spectra, even in the presence of material absorption, due to coupling between the bands and external electromagnetic plane waves. These resonances can be tuned by adjusting the photonic crystal structural properties to induce spectral selectivity in the absorbing region of semiconductors. Lastly, we demonstrate this tuning method experimentally by fabricating a proof-of-principle photonic structure consisting of a self-assembled polystyrene bead monolayer infiltrated with PbS CQDs that displays both near-infrared absorption enhancement and visible transparency enhancement over a homogeneous control film, qualitatively matching predictions and showing promise for optoelectronic applications.