Enhanced Power Conversion Efficiency in PCDTBT/PC70BM Bulk Heterojunction Photovoltaic Devices with Embedded Silver Nanoparticle Clusters
Enhanced Power Conversion Efficiency in PCDTBT/PC70BM Bulk Heterojunction Photovoltaic Devices with Embedded Silver Nanoparticle Clusters
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DOI：
10.1002/aenm.201100347
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发表时间：
2011-10-01
影响因子：
27.8
通讯作者：
Heeger, Alan J.
中科院分区：
文献类型：
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作者：
Wang, Dong Hwan;Park, Keum Hwan;Heeger, Alan J.
基于NP的Ag簇嵌入BHJ膜（1重量%）中;改进的吸收源于Ag簇的光散射。[12]图2（B）的插图示出了由BHJ中的Ag团簇的散射引起的光捕获和光学反射的示意图。银团簇通过散射和周围激发场产生的电子空穴对来增加有效光程长度。具有Ag簇的BHJ膜具有上级吸收，因为它可以通过整个波长范围散射入射光（在UV-可见光吸收设备的透射模式下，光散射类似于图2和S2中所示的吸收）。因此，具有40 nm尺寸的基于NP的Ag簇（1重量%）的PCDTBT/PC 70 BM BHJ膜在约350 nm至550 nm处具有比普通PCDTBT/PC 70 BM BHJ更大的吸光度。图3（a）至3（d）显示了普通PCDTBT/PC 70 BM BHJ和具有40 nm尺寸的基于NP的Ag簇（1重量%）的BHJ的原子力显微镜（AFM）和扫描电子显微镜（SEM）图像。单个Ag NP在膜流延期间聚集。因此，在聚合物基活性层膜的顶部形成随机分布的Ag簇。图3（c）的SEM图像还揭示了来自NP的Ag簇随机分散在活性层的顶表面上。图3（d）的SEM高分辨率图像显示Ag簇由具有明确尺寸的聚集的NP组成。
NPs based Ag clusters embedded in the BHJ film (1 wt%); the improved absorption originates in the light scattering of the Ag clusters.[12] The inset of Figure 2 (b) shows a schematic of the light trapping and optical reflection caused by the scattering from the Ag clusters in the BHJ. The Ag clusters increase the effective optical path length by means of scattering and the generation of electron-hole pairs from the surrounding excited fields of the Ag clusters. A BHJ film with Ag clusters has superior absorption because it can scatter the incident light through a whole range of wavelengths (in the transmittance mode of the UV-visible absorption equipment, the light scattering resembles the absorption shown in Figure 2 and S2.) Therefore, the PCDTBT/PC 70BM BHJ films with 40 nm-sized NPs based Ag clusters (1 wt%) have greater optical absorbance than a plain PCDTBT/PC 70BM BHJ at around 350 nm to 550 nm. Figure 3 (a) to 3 (d) show atomic force microscopy (AFM) and scanning electron microscopy (SEM) images of the plain PCDTBT/PC 70BM BHJ, and the BHJ with the 40 nm-sized NPs based Ag clusters (1 wt%). The individual Ag NPs aggregate during the film casting. Therefore, randomly distributed Ag clusters are formed on the top of the polymer-based active layer films. The SEM image of Figure 3 (c) also reveals that the Ag clusters from NPs are randomly dispersed on the top surface of active layer. The SEM high resolution image of Figure 3 (d) shows that the Ag clusters are composed of aggregated NPs with well-defined size.