Improving the performance of perovskite solar cells with glycerol-doped PEDOT:PSS buffer layer

In this paper, we investigate the effects of glycerol doping on transmittance, conductivity and surface morphology of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate))(PEDOT:PSS) and its influence on the performance of perovskite solar cells.. The conductivity of PEDOT:PSS is improved obviously by doping glycerol. The maximum of the conductivity is 0.89 S/cm when the doping concentration reaches 6 wt%, which increases about 127 times compared with undoped. The perovskite solar cells are fabricated with a configuration of indium tin oxide(ITO)/PEDOT:PSS/CH_3NH_3PbI_3/PC_(61)BM/Al, where PEDOT:PSS and PC_(61)BM are used as hole and electron transport layers, respectively. The results show an improvement of hole charge transport as well as an increase of short-circuit current density and a reduction of series resistance, owing to the higher conductivity of the doped PEDOT:PSS. Consequently, it improves the whole performance of perovskite solar cell. The power conversion efficiency(PCE) of the device is improved from 8.57% to 11.03% under AM 1.5 G(100 mW/cm~2 illumination) after the buffer layer has been modified.     

NiO_x作为空穴传输层对有机太阳能电池光吸收的影响

基于多层膜系模型的传输矩阵方法、麦克斯韦方程和光子吸收方程,研究了NiOx作为替代3,4-乙撑二氧噻吩:聚苯乙烯磺酸盐(PEDOT:PSS)的空穴传输材料对聚3-己噻吩(P3HT)和富勒烯衍生物([6,6]-phenyl-C61-butyric acid methyl ester,PC61BM)共混体异质结有机太阳能电池器件内部光电场分布和光吸收特性的影响.分别制备了以NiOx和PEDOT:PSS为空穴传输层,P3HT:PCBM为活性层的有机太阳能电池,并通过数值模拟的方法比较了NiOx和PEDOT:PSS两种空穴传输材料对器件光伏特性的影响.结果表明:10 nm的NiOx空穴传输层器件比40 nm的PEDOT:PSS器件获得了更大的短路电流和填充因子,并具有更高的能量转化效率.     

基于光学与光—电转换模型对聚合物电池功能层厚度与性能相关性分析

本文基于Forouhi-Bloomer 模型得到了这种功能层的光学常数.根据菲涅耳系数矩阵法计算了这种器件内的光电场分布,并计算了不同厚度的聚合物功能层的光子吸收数.同时,通过Onsager-Braun理论,分析了在无外加电场下聚合物功能层厚度对激子分离概率的影响.理论分析和实验结果证明:在特定的薄膜制备工艺下,器件结构为ITO/PEDOT/ P3HT:PC₆₀BM /LiF/Al时,聚合物功能层厚度在100 nm左右时,可以使器件的光子吸收数最大化,同时避免了激子分离概率的降低. 关键词： 光学常数 激子 聚合物太阳能电池     

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     

紫外臭氧处理超薄银修饰ITO电极的高效柔性有机太阳能电池

以紫外臭氧处理超薄Ag复合MoO₃或PEDOT：PSS修饰ITO电极的高效柔性有机太阳能电池。通过优化紫外臭氧处理Ag薄膜的时间,提高了以P3HT：PCBM为有源层的器件的功率转换效率,从1.68%（未经过紫外臭氧处理）提高到2.57%（紫外臭氧处理Ag 1 min）。提高的原因推测是紫外臭氧处理形成了AgO_x薄膜,提高了电荷提取并使器件具有高光学透明度、低串联电阻和优异的表面功函数等一些性能。并且,紫外臭氧处理Ag薄膜与MoO₃或者PEDOT：PSS复合修饰ITO的器件效率分别得到提高,Ag薄膜与MoO₃复合修饰ITO的器件效率从2.02%（PET/ITO/MoO₃）提高到2.97%（PET/ITO/AgO_x/MoO₃）,Ag薄膜与PEDOT：PSS复合修饰ITO的器件效率从2.01%（PET/ITO/PEDOT：PSS）提高到2.93%（PET/ITO/AgO_x/PEDOT：PSS）。此外,以PBDTTT-EFT：PC₇₁BM为有源层的柔性聚合物太阳能电池效率可达6.21%。基于ITO的柔性光电器件效率的提高主要归于ITO被Ag/PEDOT：PSS或Ag/MoO₃修饰后功函数的提高。     

DPVBi空穴阻挡层对OLED性能的优化

研究了宽带隙有机小分子材料DPVBi作为空穴阻挡层对OLED器件效率和亮度的优化作用.DPVBi的引入有效地改善了以PEDOT:PSS做空穴注入层的OLED器件的空穴过剩问题.实验结果表明:通过优化DPVBi的厚度,插入30 nm厚的DPVBi空穴阻拦层可以有效地平衡OLED器件的电子和空穴浓度,降低器件的工作电压,优...     

Au nanorods-incorporated plasmonic-enhanced inverted organic solar cells

The effect of Au nanorods(NRs) on optical-to-electric conversion efficiency is investigated in inverted polymer solar cells, in which Au NRs are sandwiched between two layers of Zn O. Accompanied by the optimization of thickness of Zn O covered on Au NRs, a high-power conversion efficiency of 3.60% and an enhanced short-circuit current density(J SC) of10.87 m A/cm2 are achieved in the poly(3-hexylthiophene): [6,6]-phenyl-C61-butyric acid methyl ester(P3HT:PC60BM)-based inverted cell and the power conversion efficiency(PCE) is enhanced by 19.6% compared with the control device. The detailed analyses of the light absorption characteristics, the simulated scattering induced by Au NRs, and the electromagnetic field around Au NRs show that the absorption improvement in the photoactive layer due to the light scattering from the longitudinal axis and the near-field increase around Au NRs induced by localized surface plasmon resonance plays a key role in enhancing the performances.     

Plasmon enhanced light absorption in bulk heterojunction organic solar cells

Silver nanospheres (Ag NSs) buffer layers were introduced via a solution casting process to enhance the light absorption in poly (3‐hexylthiophene) (P3HT) and [6,6]‐phenyl‐C61 butyric acid methyl ester (PCBM) bulk heterojunction organic solar cells. These Ag NSs, as surface plasmons, could increase the optical electric field in the photoactive layer whilst simultaneously improving the light scattering. As a result, this buffer layer improves the light absorption of P3HT:PCBM blend and consequently improves the external quantum efficiency (EQE) of organic solar cells. In this work, different sizes of Ag NSs plasmon‐enhanced layer were investigated, with the aim of optimizing the performance of devices. UV‐vis spectrometer measurement demonstrates that the total optical absorption of P3HT:PCBM blend films in the spectral range of 350–650 nm is increased by ～4 and 6% with incorporation of the 20 and 40 nm Ag NSs, respectively. The J_sc was shown to increase by ～21 and 24% for 20 and 40 nm Ag NSs, respectively. This is due to the extra photogenerated excitons by the plasmonic resonance of Ag NSs. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Overcoming the thickness paradox: Systematical optimization of inverted polymer solar cells

Inverted structure comes out to be a promising alternative for making polymer solar cells (PSC) with high efficiency and long-term stability. Vertically stacked functional layers with planar shapes often suffer contradictions in holding high optical absorption and excellent charge transfer/hindrance capability to construct well performed inverted PSC devices. Here, we give an example of rational control of the thickness of electron transport layer (ETL), hole transport layer (HTL) and organic active layer (OAL) to achieve a synergistic effect on promoting the overall photovoltaic behaviors. With in-depth exploration of the interaction between device performance and layer thickness, we obtain the optimized device ITO/ZnO Ncs (45 nm)/P3HT:PCBM (70 nm)/MoO₃ (1 nm)/Ag (70 nm) exhibiting an V_oc of 0.63 V, J_sc of 12.52 mA/cm², FF of 54% and PCE of 4.26%.     

一种采用Li3N掺杂电子注入层的底发射倒置结构OLED的制备

采用Li3N掺杂电子注入层Alq3∶Li3N,制作了一种结构为ITO/Alq3 Alq3∶Li3N/Alq3/NPB/MoO3/Al的倒置底发射有机发光器件.其中ITO玻璃作为透明阴极,金属Al作为顶部阳极,在ITO阴极与电子传输层之间加入Li3N n型掺杂层,改善了该器件的电子注入和传输能力|在Al阳极与空穴传输层之间加入MoO3缓冲层,降低了Al阳极与NPB之间较大的空穴注入势垒,改善了空穴注入能力.实验表明:此结构的倒置底发射有机发光器件性能可达到传统结构的常用有机发光器件如ITO/NPB/Alq3/LiF/Al的性能,完全可以满足非晶硅薄膜晶体管有源有机发光器件中驱动电路的匹配及性能要求.     

Influence of morphology of PCDTBT:PC71BM on the performance of solar cells

Because of the restriction of low energy difference between the highest occupied molecular orbital of P3HT and the lowest unoccupied molecular orbital of PCBM, the obtained power conversion efficiency of P3HT:PCBM solar cells is merely half the ideal value. In this paper, we have fabricated bulk heterojunction solar cells based on PCDTBT and PC71BM (structure: ITO/PEDOT:PSS/PCDTBT:PC71BM/LiF (0.8 nm)/Al (80 nm)). In order to optimize the performance of the cells, the weight ratio of PCDTBT to PC71BM, the thickness of the active layer and thermal annealing are investigated. When the weight ratio of PCDTBT to PC71BM is 1:2 and the thickness of the active layer is 73 nm, a short circuit current density of 10.36 mA/cm², an open-circuit voltage of 0.91 V, a fill factor of 55.06 % and a power conversion efficiency of 5.19 % can be achieved. Moreover, we probe the influence of annealing temperature on the performance of organic solar cells, and find that the thermal treatment methodology (apart from the removal of trapped casting solvent) is of limited benefit.     

基于苯并二噻吩聚合物所制备的三元光电探测器的特性

本文采用P3HT∶PTB7∶PC⁶¹BM为活性层,制备了覆盖可见光范围的三元体异质结有机光电探测器(organic photodetectors,OPDs).利用原子力显微镜、紫外可见吸收光谱和荧光光谱等手段研究了PTB7添加到P3HT∶PC61BM体系中对OPDs光学和电学性质的影响,发现当P3HT∶PTB7∶PC61BM的质量比为8∶2∶10时,三元混合层的响应光谱扩展到780 nm,OPDs的响应度R在630,530,460 nm的光照和–1 V偏压下分别达到178,291,241 mA/W,比探测率D^*达到10¹² Jones,并与课题组之前成果P3HT∶PBDT-TT-C∶PC61BM为活性层的三元有机光电探测器做了对比.分析了两种基于苯并[1,2-b∶4,5-b]二噻吩(BDT)单元的聚合物PTB7与PBDT-TT-C分别添加到同一体系P3HT∶PC₆₁BM中产生的器件性能差距的现象,解释了PTB7由于氟原子的引入,对混合薄膜微观形貌的影响和对薄膜中光生载流子迁移率的提升的原因.这为制备性能更好的有机光电探测器提供了理论依据和方法.     

Electronic processes at the interfaces between photoactive layers and TiO<Subscript> <Emphasis Type="Italic">x</Emphasis> </Subscript> buffer layers in organic solar cells

The effect a layer of TiO_x located between a photoactive layer and a metallic Al electrode has on the photovoltaic properties of an organic solar cell based on P3HT:PC₇₀BM polymer is studied. The optimum thickness of the TiO_x layer at which the efficiency of the solar cells is highest and the TiO_x layer ensures the transfer of electrons from the photoactive polymer layer to the electrode while blocking vacancies is found to be 10 nm. The effect oxygen has on electronic processes during the operation of the photovoltaic cell is discussed.     

通过插入Au薄膜改善绿光OLED器件的发光色纯度

在一些有机电致发光器件中,Au常被用作阳极,研究者希望Au在导电的同时兼具半透明可出光的属性,这要求Au在能导电的同时厚度要尽量薄。因此制备两种金属共同组成电极成为了选择。将半透明Au/Al层插入阳极一侧,制备了结构为ITO/Al(16 nm)/Au(10 nm)/TPD(30 nm)/AlQ(30 nm)/LiF(0.5 nm)/Al的OLED器件,相对于器件ITO/TPD(30 nm)/AlQ(30 nm)/LiF(0.5 nm)/Al在长波方向出现了光谱窄化现象,通过分析和实验判断该现象是Au薄膜特有的对光的选择透过性造成,而并非微腔效应。阳极一侧加入了Au/Al的器件保持了广视角无角度依赖的优点,同时可以输出滤掉部分红光的纯度更高的发光,发光色纯度得到了改善。     

Dual plasmonic‐enhanced bulk‐heterojunction solar cell incorporating gold nanoparticles into solution‐processed anode buffer layer and active layer

A dual plasmonic resonance effect on the performance of poly(3‐hexylthiophene) (P3HT):phenyl C61‐butyricacid methyl ester (PC61BM) based polymer solar cells (PSCs) has been demonstrated by selectively incorporating 25 nm colloidal gold nanoparticles (Au NPs) in a solution‐processed molybdenum oxide (MoO₃) anode buffer layer and 5 nm colloidal Au NPs in the active P3HT:PCBM layer. The devices exhibit up to ～20% improvement in power conversion efficiency which is attributed to the dual effect of localized surface plasmon resonance (LSPR) of Au NPs with enhanced light absorption and exciton generation. Our report shows a guideline on the usage of dual LSPR effect for the solution‐processed polymer solar cells to achieve high efficiencies. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

High-efficiency Simple Structure White Organic Light-emitting Devices Based on Rubrene Ultrathin Layer

White organic light-emitting devices (WOLEDs) were fabricated with an ultrathin layer of rubrene inserted between NPB and TPBI. With a simple three-layer structure of ITO/NPB(50 nm)/rubrene(0.1 nm)/TPBI(50 nm)/LiF/Al, a white light with CIE coordinates of (0.31, 0.30) were generated. The device gave a maximum luminance efficiency of 2.04 lm/W at 5 V. Furthermore, with a multilayer structure of ITO/m-MTDATA(30 nm)/NPB(20 nm)/rubrene(0.1 nm)/TPBI(40 nm)/Alq₃(10 nm)/LiF/Al, the device reached a maximum luminance efficiency of 4.29 lm/W at 4 V and the luminance could exceed 10 000 cd/m² at 10 V.     

利用不同阴极缓冲层来改善Pentacene/C60太阳能电池的性能

制备了结构为ITO/Pentacene/C₆₀/Al的双层光伏电池器件,在C₆₀/Al界面插入了常用的缓冲层材料bathocuproine(BCP)作为阴极缓冲层,通过优化BCP层的厚度来提高电池的性能并研究了阴极缓冲层的作用机理.实验发现,BCP厚度为10 nm时器件的效率最高,为0.46%.在此基础上,利用bathophenanthroline(Bphen)和3,4,9,10-Perylenetetracarb-oxylicdianhydride(PTCDA 关键词： 有机太阳能电池 Pentacene 60')" href="#">C₆₀ 缓冲层     

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%。     

基于金颗粒自组装烷基硫醇为缓冲层的有机太阳能电池

有机活性层和无机电极的界面修饰影响到有机太阳能电池性能。本文引入金纳米颗粒自组装烷基硫醇,改善有机/无机的界面。制备“ITO/金颗粒-硫醇自组装缓冲层/聚3-己基噻吩(P3HT)∶[6,6]-苯基-C61-丁酸甲酯(PCBM)/LiF/Al电极”结构的器件。自组装硫醇防止了因金颗粒与活性层直接接触导致的激子猝灭效应。我们研究了金纳米颗粒自组装不同链长的烷基硫醇对器件性能的影响,烷基硫醇的烷基链越长,硫醇对金颗粒的覆盖性越好,器件的短路电流越高。金纳米颗粒自组装十二烷基硫醇,短路电流J_SC由5.19 mA·cm-2提升到6.24 mA·cm-2,提高了20%。     

Nanosilver surface plasmon response enhanced the photovoltaic performance of organic solar cells

Nanosilver island thin films with different thickness were synthesized by vacuum vapor deposition between ITO and PEDOT:PSS for organic solar cells, forming the structure of ITO/AgNPs layer/PEDOT:PSS/P3HT:PCBM/LiF/Al. Surface morphology and UV–vis absorption spectrum were investigated by AFM and UV–vis scanning spectrophotometer. It was found that after adding the nanosilver film, the optical properties of the device were enhanced with increasing the thickness of nanosilver island films. When the thickness of nanosilver thin films is 3.0 nm, the most significant surface plasmon response and red-shift of the resonance absorption peak appeared. Meanwhile, short circuit current density of the device increased from 9.93 mA/cm² to 12.98 mA/cm², the fill factor increased from 49.35% to 52.79% and the power conversion efficiency increased from 3.05% to 4.01%. These results provided a theoretical guidance to optimize the design and increase the performance of solar cells.