金属纳米颗粒对有机太阳能电池光吸收效率影响的研究

借助时域有限差分法,对几种常见金属纳米颗粒影响有机太阳能电池光吸收效率的因素及其内部物理机制进行了研究.首先对金属纳米颗粒激发局域表面等离子共振的场分布特点进行分析,对比其在电池不同功能层中对光吸收率的影响;其次基于米氏理论与电共振效应,得出金属纳米颗粒的结构参量对局域表面等离子共振位置及强度的影响规律,并以此进行优化设计.结果表明,具有高对称性形貌的金属纳米颗粒以小尺寸密堆积结构引入电池活性层,能够促进电池光吸收增强三倍以上.     

Al纳米颗粒增强微晶硅薄膜太阳电池光吸收的模拟研究

利用价格低廉、性能优良的金属纳米颗粒增强太阳电池的光吸收具有广阔的应用前景. 通过建立三维数值模型, 模拟了微晶硅薄膜电池前表面周期性分布的Al纳米颗粒阵列对电池光吸收的影响, 并对其结构参数进行了优化. 模拟结果表明: 对于球状Al纳米颗粒阵列, 影响电池光吸收的关键参数是周期P与半径R的比值, 或者说是颗粒的表面覆盖度; 当P/R=4–5时, 总的光吸收较参考电池提高可达20%. 与球状颗粒相比, 优化后的半球状Al纳米颗粒阵列可获得更好的陷光效果, 但后者对颗粒半径R的变化较敏感. 另外, 结合电场分布, 对电池光吸收增强的物理机理进行了分析.     

Ag纳米颗粒对有机小分子太阳能电池性能的改善

在有机小分子太阳能电池CuPc/C60和TiOPc/C60的阳极ITO表面分别制备了一层Ag纳米颗粒,并采用MoO3作为阳极缓冲层,器件的性能均得到有效改善.Ag纳米颗粒的引入所形成的表面等离子激元共振可显著提高有机光活性层的吸收效率和光生激子的分解效率;而MoO3有效抑制了光生激子在有机/金属界面处发生的猝灭,提高了...     

金属纳米颗粒LSPR光纤生物传感DDA方法研究

研究了金属纳米颗粒的局部表面等离子体共振(LSPR)行为,并讨论了其在光纤生物传感领域的应用.采用离散偶极近似(DDA)的方法,从理论上分析了金属纳米颗粒的尺寸、形状对其传感灵敏度的影响.计算结果显示,金属纳米颗粒的等离子共振吸收峰同时受到颗粒尺寸和形状的影响,但形状对其传感灵敏度的影响最为明显,计算结果与实验数据能较好地吻合.     

金属/介质/金属光栅结构强化吸收特性

本文从电磁场理论出发,研究了单层光栅的金属/介质/金属结构的共振,利用严格耦合波方法计算了金属/介质/金属光栅结构表面的光谱特性,利用金属/介质/金属膜层结构的色散关系和等效LC回路模型两种理论对金属/介质/金属光栅结构表面的共振现象进行研究,讨论了几何参数对金属/介质/金属光栅结构共振的影响,结果表明单层光栅的金属/介质/金属结构的共振由金属/介质界面上的表面等离子极化之间的耦合产生。     

降低表面等离子激元寄生吸收损失的途径研究

从纳米Ag颗粒表面等离子激元光学及表面高能电场特性两方面入手,较为系统地研究了周围介质的导电特性对表面等离子激元的影响.通过对复合薄膜紫外-可见-近红外光谱及表面增强拉曼散射光谱的分析,指出绝缘性的Al₂O₃介质薄膜能够起到良好的表面电场定域效果,且不会引入附加的光吸收损失;而导电性的ITO薄膜则会引入表面价电子的溢出损失,加速了表面电场的衰逝,同时引起长波方向上显著的光吸收损失.研究还表明致密的Al₂O₃介质薄膜能够起到良好的屏蔽作用,且纳米Ag颗粒表面等离子激元特性仅受最近邻材料特性的影响.研究结果为在硅基薄膜太阳电池中实现对纳米Ag颗粒的阻挡、寄生光吸收损失的降低以及表面高能电场的利用,提供了一条有效的解决途径.     

SiO_2/Ag核壳结构纳米粒子的制备及其表面荧光增强

以罗丹明B掺杂的SiO2球为核,通过化学还原的方法制备了二氧化硅/银核壳结构复合纳米粒子。采用透射电镜(TEM)、紫外-可见-近红外(UV-Vis-NIR)分光光度计和荧光分光光度计对二氧化硅/银核壳结构纳米粒子的表面形貌、表面等离子共振和表面荧光增强特性进行了研究和表征。结果表明,二氧化硅/银核壳结构纳米粒子的表面等离子共振峰具有明显的可调谐性,且其表面荧光增强强烈依赖于银壳层的表面等离子共振,随银壳层厚度的增大而增强。     

级联亚波长平面介质栅偏振分束器研究

提出了一种纳米厚度金属层连接的级联亚波长平面介质光栅三明治结构,利用该结构中纳米金属连接层上下界面处的表面等离子共振的互作用形成多波长共振的特点设计了适用于光通信波段（1 300～1 600nm）高性能的宽带偏振器和宽带偏振分束器。利用严格耦合波理论分析发现偏振分束器带宽主要由金属连接层厚度控制,光栅厚度基本不影响偏振分束器带宽,只影响共振深度和共振波长。该结论为后续的制备提供了理论指导和借鉴作用。     

纳米银增强聚合物太阳能电池光吸收的研究

基于共轭聚合物给体材料P3HT和富勒烯衍生物受体材料PCBM共混的体异质结结构 的聚合物太阳能电池因其空穴载流子迁移率低而限制了P3HT:PCBM功能层厚度, 从而影响了器件对入射光的吸收. 在聚合物功能层内引入金属纳米颗粒可以利用金属表面等离子体效应增强器件内电场并改善器件的光吸收. 本文基于时域有限差分法(finite difference time domain, FDTD)方法模拟得到了聚合物功能层内包含了直径为50 nm纳米银球并且球间距为50 nm的聚合物太阳能 电池器件在波长分别为400 nm和500 nm照射时的二维光电场分布以及入射角分别为15°, 45°, 60°时包覆纳米银聚合物功能层横截面内的光电场强度分布; 计算得到了银纳米颗粒尺寸分别为10 nm, 20 nm和50 nm时以及分布在空穴传输层PEDOT:PSS的纳米银器件的光吸收; 并计算了斜入射时包覆纳米银的聚合物功能层光吸收. 理论分析表明: 聚合物功能层加入纳米银球后, 因为纳米银球的表面等离子体效应使入射光在功能层内散射增强而使器件内的光电场重新分布; 直径较大的纳米银颗粒能产生大角度的光散射, 更有利于聚合物功能层对光的吸收. 这里, 基于有机银盐还原法制备了纳米银颗粒并制备了银等离子体增强的聚合物太阳能电池, 其结构为: glass/ITO (～100 nm)/PEDOT:PSS (40 nm)/P3HT:PCBM (～100 nm)(nano-Ag)/LiF (1 nm)/Al (120 nm). 该器件与平板器件的性能对比实验证实: 通过在聚合物功能层内上引入纳米银颗粒可以有 效增加器件光吸收并改善器件电学性能, 器件外量子效率在520 nm处最大增加了17.9%. 关键词： 纳米银 表面等离子体共振 时域有限差分 聚合物太阳能电池     

脉冲激光沉积Ag:BaTiO3纳米复合薄膜及其光学特性

在MgO(100)基片上利用脉冲激光沉积技术制备了掺有Ag纳米颗粒的BaTiO₃复合薄膜.通过X射线衍射对薄膜的结构进行了表征,利用透射电子显微镜对Ag纳米颗粒的尺寸、形态进行了观测,X射线光电子能谱结果表明Ag呈金属态.在410—500nm范围内观测到了Ag纳米颗粒引起的等离子振荡峰,随着后处理温度和Ag颗粒浓度的增加,吸收峰发生红移,并出现了双峰现象. 关键词： 金属纳米复合薄膜 激光沉积 光吸收     

Nano Ag-enhanced photoelectric conversion efficiency in all-inorganic,hole-transporting-layer-free CsPbIBr2 perovskite solar cells

All-inorganic, hole-transporting-layer-free CsPbIBr₂ perovskite solar cells have great potential for development, but their device performance needs to be further improved. Recently, metal nanostructures have been successfully applied in the field of solar cells to improve their performance. Nano Ag-enhanced power conversion efficiency (PCE) in one CsPbIBr₂ perovskite solar cell utilizing localized surface plasmons of Ag nanoparticles (NPs) on the surface has been researched experimentally and by simulation in this paper. The localized surface plasmon resonance of Ag NPs has a near-field enhancement effect, which is expected to improve the light absorption of CsPbIBr₂ perovskite photovoltaic devices. In addition, Ag NPs have a forward-scattering effect on the incident light, which can also improve the performance of CsPbIBr₂-based perovskite photovoltaic devices. By directly assembling Ag NPs (with a size of about 150 nm) on the surface of fluorine-doped tin oxide it is found when the particle surface coverage is 10%, the CsPbIBr₂ perovskite photovoltaic device achieves a best PCE of 2.7%, which is 9.76% higher than that of the control group. Without changing any existing structure in the ready-made solar cell, this facile and efficient method has huge applications. To the best of our knowledge, this paper is the first report on nano Ag-enhanced photoelectric conversion efficiency in this kind of CsPbIBr₂ perovskite solar cell.     

Improving power conversion efficiency of perovskite solar cells by cooperative LSPR of gold-silver dual nanoparticles

Enhancing optical and electrical performances is effective in improving power conversion efficiency of photovoltaic devices. Here, gold and silver dual nanoparticles were imported and embedded in the hole transport layer of perovskite solar cells. Due to the cooperative localized surface plasmon resonance of these two kinds of metal nanostructures, light harvest of perovskite material layer and the electrical performance of device were improved, which finally upgraded short circuit current density by 10.0%, and helped to increase power conversion efficiency from 10.4% to 11.6% under AM 1.5G illumination with intensity of 100 m W/cm~2. In addition, we explored the influence of silver and gold nanoparticles on charge carrier generation, dissociation, recombination, and transportation inside perovskite solar cells.     

层层自组装金纳米粒子表面等离子体引发光电流应用于等离子体增感太阳能电池

等离子体增感太阳能电池中,层层自组装金纳米粒子的表面等离子体共振能产生光电电流,金纳米粒子层的光电转换效率随表面等离子体共振强度的提升而增加。等离子体增感太阳能电池初步试验光电转换效能为0.75%。利用模型仿真电荷分离的现象、光电电流的产生,以及表面等离子体共振和光电电流产生之间的关系来解释实验结果。在未来,通过优化等离子体增感太阳能电池组件,可以进一步提升其转换效率。这在表面等离子体激活太阳能电池及等离子体太阳能电池领域将有很大应用潜力。     

Enhancement of light trapping in thin-film solar cells through Ag

Forward-scattering efficiency (FSE) is first proposed when an Ag nanoparticle serves as the light-trapping structure for thin-film (TF) solar cells because the Ag nanoparticle’s light-trapping efficiency lies on the light-scattering direction of metal nanoparticles.Based on FSE analysis of Ag nanoparticles with radii of 53 and 88 nm,the forward-scattering spectra and light-trapping efficiencies are calculated.The contributions of dipole and quadrupole modes to light-trapping effect are also analyzed quantitatively.When the surface coverage of Ag nanoparticles is 5%,light-trapping efficiencies are 15.5% and 32.3%,respectively,for 53and 88-nm Ag nanoparticles.Results indicate that the plasmon quadrupole mode resonance of Ag nanoparticles could further enhance the light-trapping effect for TF solar cells.     

Enhancement of photoluminescence of the CdSe/CdS quantum dots on quartz substrates in the presence of silver nanoparticles

Multilayer systems consisting of layers of hybrid quantum dots are fabricated. The quantum dots with the CdSe/CdS core/shell structure are chemically synthesized and deposited on the surface of quartz glass that contains ion-synthesized silver nanoparticles in the near-surface region. Silver nanoparticles exhibit optical absorption owing to the localized surface plasmon resonance. Variations in the photoluminescence intensity of the layer related to an increase in the distance from the quartz surface with metal nanoparticles are studied. An increase in the photoluminescence intensity is observed under excitation in the spectral region of the plasmon absorption of silver nanoparticles. An optimal distance between the layers is determined to maximize the enhancement of the photoluminescence of quantum dots in the presence of the near field of metal nanoparticles.     

High efficiency nanotextured silicon solar cells

We report the computational modeling of forward scattering phenomena arising in Au nanoparticles array near their localized surface plasmon resonance, which by producing a strong field enhancement effect on the substrate leads to higher optical absorption and, therefore, higher efficiencies of operation. Computational calculations indicate that the ultimate efficiency of an optimized silicon nanoholes (SiNH) array texture surface in combination with the surface and bottom-of-a-trench Au nanoparticles array described herein, is 39.67%, which compares favorably with the ultimate efficiency of 31.11% for an optimized silicon nanoholes array texture surface. Furthermore, the utilization of an optimized silicon nitride antireflection coating increases the ultimate efficiency to a promising value of 41.88%, while the utilization of a single-crystal silicon layer of thickness 2.8 μm will be instrumental in drastically reducing solar cell manufacturing cost.     

银纳米颗粒对聚合物太阳能电池性能的提高

采用水溶性银纳米颗粒附着在反型太阳能电池的电子传输层上,用以提高有机太阳能电池的短路电流。所制备的器件结构为ITO/ZnO/Ag NPs/P3HT(Poly 3-hexylthiophene):PC_[60]BM/MoO₃/Ag。其金属银纳米颗粒的表面等离激元在410 nm处出现了共振吸收峰,半峰全宽约为60 nm。器件的光电流在可见光范围内均有所增加,短路电流相对于标准器件提高了20.2%,光电转化效率相对提高了17.2%。     

表面等离子体-微腔激元对顶入射有机薄膜太阳能电池光吸收效率的增强

为了提高顶入射有机薄膜太阳能电池(TOSCs)的光吸收效率,我们将周期性矩形光栅结构引入到TOSCs中,分析了具有光栅结构的空气/Ag_1/有源层/Ag_2/空气(IMIMI)结构理想模型中复合表面等离子激元(SPPs)与微腔模式的耦合机制。通过调节光栅周期和有源层厚度,实现了复合SPPs、微腔模式以及有机材料本征吸收3个区域的重合。由于复合SPPs与微腔模式的反交叉耦合作用形成了表面等离子体-微腔激元,其局域场增强作用有效地提高了有源层的光吸收效率,提高了近19%。