基于聚多巴胺/氧化锌复合阴极缓冲层的倒置聚合物太阳能电池的研究

利用多巴胺氧化自聚合形成聚多巴胺(PDA)与ZnO结合形成PDA/ZnO复合阴极缓冲层,制备了以P3HT:PC_(61)BM为活性层的倒置结构聚合物太阳能电池,通过改变PDA的自聚合时间来分析复合阴极缓冲层对器件性能的影响.实验发现,随着PDA的自聚合时间的增加,聚合物太阳能电池的光电转换效率先增大后减小,当自聚合时间为10 min时,相应器件光伏性能达到最优值,其开路电压V_(OC)为0.66 V,短路电流密度J_(SC)为9.70 mA/cm~2,填充因子FF为68.06%,光电转换效率PCE为4.35%.器件性能改善的原因是由于PDA/ZnO复合阴极缓冲层减小了ZnO与ITO之间的接触电阻,同时PDA中存在大量的氨基有利于倒置太阳能电池阴极对电子的收集.     

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     

MoO3/Ag/MoO3 top anode structure for semitransparent inverted organic solar cells

In this study, we fabricated semitransparent polymeric solar cells with an inverted structure, with the structure being indium tin oxide (ITO)/cesium carbonate (Cs₂CO₃)/poly(3-hexylthiophene) (P3HT):1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61(PCBM)/transparent multilayer. The structure of the transparent multilayer (DMD multilayer), which acted as the anode, was MoO₃ (1–40 nm)/Ag (10 nm)/MoO₃ (0–80 nm). The inner MoO₃ layer showed a great performance changes depending on the variation of thickness, while the outer MoO₃ layer showed relatively slight changes. The best performance was observed with the of anode DMD multilayer thickness of 6/10/40 nm and with the illumination from the ITO side in organic solar cell devices. High performance result was observed in high reflectance and low transmittance of the DMD layer.     

Improved performance of polymer solar cells by using inorganic,organic, and doped cathode buffer layers

The interface between the active layer and the electrode is one of the most critical factors that could affect the device performance of polymer solar cells. In this work, based on the typical poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester(P3HT:PCBM) polymer solar cell, we studied the effect of the cathode buffer layer(CBL) between the top metal electrode and the active layer on the device performance. Several inorganic and organic materials commonly used as the electron injection layer in an organic light-emitting diode(OLED) were employed as the CBL in the P3HT:PCBM polymer solar cells. Our results demonstrate that the inorganic and organic materials like Cs_2CO_3, bathophenanthroline(Bphen), and 8-hydroxyquinolatolithium(Liq) can be used as CBL to efficiently improve the device performance of the P3HT:PCBM polymer solar cells. The P3HT:PCBM devices employed various CBLs possess power conversion efficiencies(PCEs) of 3.0%–3.3%, which are ca. 50% improved compared to that of the device without CBL. Furthermore, by using the doped organic materials Bphen:Cs_2CO_3 and Bphen:Liq as the CBL, the PCE of the P3HT:PCBM device will be further improved to 3.5%, which is ca. 70% higher than that of the device without a CBL and ca. 10% increased compared with that of the devices with a neat inorganic or organic CBL.     

Photocurrent analysis of organic photovoltaic cells based on CuPc/C60 with Alq3 as a buffer layer

The performance of an organic photovoltaic(OPV) cell based on copper phthalocyanine CuPc/C60 with a tris(8-hydroxyquinolinato) aluminum(Alq3) buffer layer has been investigated.It was found that the power conversion efficiency of the device was 1.51% under illumination with an intensity of 100 mW/cm2,which was limited by a squareroot dependence of the photocurrent on voltage.The photocurrent-optical power density characteristics showed that the OPV cell had a significant space-charge limited photocurrent with a varied saturation voltage and a three quarters power dependence on optical power density.Also,the absorption spectrum was measured by a spectrophotometer,and the results showed that the additional Alq3 layer has a minor effect on photocurrent generation.     

Effects of NPB anode buffer layer on charge collection in ZnO/MEH-PPV hybrid solar cells

We investigate the effects of （N,N’-diphenyl）-N,N’-bis（1-naphthyl）-1,1’-biphenyl-4,4’-diamine （NPB） buffer layers on charge collection in inverted ZnO/MEH-PPV hybrid devices. The insertion of a 3-nm NPB thin layer enhances the efficiency of charge collection by improving charge transport and reducing the interface energy barrier, resulting in better device performances. S-shaped light J–V curve appears when the thickness of the NPB layer reaches 25 nm, which is induced by the inefficient charge extraction from MEH-PPV to Ag. Capacitance–voltage measurements are performed to further investigate the influence of the NPB layer on charge collection from both simulations and experiments.     

Rubrene作电子传输层的异质结有机太阳能电池

以Rubrene为电子传输层(ETL),制备了结构为ITO/MoO3(5nm)/Rubrene(50nm)/C60(45nm)/Rubrene(0,3,5.5,9.5nm)/Al(130nm)的有机太阳能电池.与没有ETL的器件相比,含5.5nmRubrene的电池的开路电压、填充因子、功率转换效率分别从0.68V,0.488,0.315%增加到0.86V,0.574,0.490%.实验结果分析表明:热的Al原子直接沉积在C60上,破坏了C60层,形成高功函数的C60/Al阴极,弱化内建电场,降低电池性能;当插入ETL后,C60层得到保护,热的Al原子沉积破坏了Rubrene层,形成了缺陷态能级,提高电池的内建电场,促进了电子的传输.进一步的单电子电池实验表明,缺陷态能级低于C60的最低未占据分子轨道.     

Enhanced charge carrier injection in heterojunction organic field-effect transistor by inserting an MoO3 buffer layer

A top-contact organic field-effect transistor(OFET) is fabricated by adopting a pentacene/1,1’-bis(di-4tolylaminophenyl) cyclohexane(TAPC) heterojunction structure and inserting an MoO3 buffer layer between the TAPC organic semiconductor layer and the source/drain electrode.The performances of the heterojunction OFET,including output current,field-effect mobility,and threshed voltage,are all significantly improved by introducing the MoO3 thin buffer layer.The performance improvement of the modified heterojunction OFET is attributed to a better contact formed at the Au/TAPC interface due to the MoO3 thin buffer layer,thereby leading to a remarkable reduction of the contact resistance at the metal/organic interface.     

Performance improvements of organic solar cell using dual cathode buffer layers

The present study deals with the effect of dual cathode buffer layer (CBL) on the performance of bilayer of 4,4′-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC) and fullerene (C70)-based organic solar cell (OSC) with low donor concentration. OSC devices with CBLs have been fabricated using thermal vapor deposition technique. We report the use of lithium fluoride (LiF) and molybdenum trioxide (MoO₃) as CBLs. The insertion of LiF between C70 and aluminium (Al) electrode enhances the power conversion efficiency (PCE) of device from 1.89% to 2.47% but quenching of photogenerated excitons is observed at interface of C70 and LiF layers. Incorporation of MoO₃ between LiF and Al electrode further enhances PCE of device to 3.51%. This has also improved the material quality and device properties, by preventing the formation of gap states and diminishing exciton quenching.     

基于Al_2O_3/MoO_3复合阳极缓冲层的倒置聚合物太阳能电池的研究

采用旋涂Al_2O_3前驱体溶液和低温退火的方法在活性层上形成Al_2O_3薄膜,并与MoO_3结合形成Al_2O_3/MoO_3复合阳极缓冲层,制备了以聚3-己基噻吩:[6.6]-苯基-C_(61)-丁酸甲酯(P3HT:PC_(61)BM)为活性层的倒置聚合物太阳能电池,并通过改变Al_2O_3前驱体溶液的浓度来分析复合阳极缓冲层对器件性能的影响.结果发现,Al_2O_3/MoO_3复合阳极缓冲层能有效调控倒置聚合物太阳能电池的光电性能及其稳定性.当Al_2O_3前驱体溶液的浓度为0.15%时,器件光伏性能达到最优值,与MoO_3单缓冲层的器件相比,光电转换效率(PCE)由3.85%提高到4.64%;经过80天老化测试后,具有复合阳极缓冲层的器件PCE保留为初始值的76%,而单缓冲层的器件PCE已经下降到50%以下.器件性能得到改善的原因是Al_2O_3/MoO_3复合阳极缓冲层增强了倒置太阳能电池器件阳极对空穴的收集能力,同时钝化了器件活性层,从而提升了太阳能电池器件的光伏性能及其稳定性.     

PTCBI作为阴极修饰层对Rubrene/C70器件性能的影响

制备了结构为ITO/MoO₃(6 nm)/Rubrene (30 nm)/C₇₀ (30 nm)/PTCBI(x nm)/Al (150 nm)器件, 研究了四羧基苝的衍生物PTCBI作为阴极修饰层对Rubrene/C₇₀有机太阳能电池的作用. 实验结果显示, 在C₇₀与Al电极之间插入PTCBI 后, 电池性能得到明显改善; 分析表明, 插入PTCBI后, 活性层与阴极形成了良好的欧姆接触, 提高了器件的内建电场, 同时PTCBI避免了激子与Al电极的接触, 减少了在制备过程中高动能Al对C₇₀的破坏. 进一步考察了PTCBI厚度对电池的性能的影响, 结果显示, 厚度为6 nm的PTCBI 层器件性能最佳, 其开路电压(V_OC)、填充因子(FF)、短路电流密度(J_SC)与功率转换效率(ηP)与未插入PTCBI修饰层的器件相比分别提高了70.4%, 55.5%, 125.1%, 292.2%. 当PTCBI的厚度大于6 nm时, 激子解离后产生的自由电子会在PTCBI与阴极界面积累, 导致器件J-V曲线出现S形.     

阴极修饰层对 SubPc/C60 倒置型有机太阳能电池性能的影响

采用Cs₂CO₃, 石墨烯(graphene):Cs₂CO₃混合材料和 ZnO 纳米颗粒作为阴极修饰材料, 研究了不同阴极界面修饰层对基于SubPc/C₆₀的倒置结构的有机太阳能电池性能的影响. 结果表明: 引入适当厚度的阴极修饰层, 可以提高器件的性能和稳定性; 尤其是基于Cs₂CO₃以及graphene:Cs₂CO₃混合阴极修饰层的光伏器件, 能量转换效率(PCE)提高了2倍; 同时, 采用ZnO纳米颗粒作为阴极修饰层的器件, 开路电压(V_OC)达到0.89 V, 并且器件的PCE 提高了4倍多. 此外, 不同电极修饰材料和倒置结构的引入可以有效防止器件串连电阻的升高, 从而提高器件的稳定性. 关键词： 倒置型 阴极修饰层 有机太阳能电池 稳定性     

Effect of net carriers at the interconnection layer in tandem organic solar cells

Tandem cell with structure of indium tin oxide (ITO)/molybdenum oxide (MoO₃)/fullerene (C60)/copper phthalocyanine (CuPc)/C60/tris-8-hydroxy-quinolinato aluminum (Alq₃)/Al was fabricated to study the effect of net carriers at the interconnection layer. The open circuit voltage and short circuit current were found to be 1.15 V and 0.56 mA/cm², respectively. Almost the same performance (1.05 V, 0.58 mA/cm²     

Short-circuit current improvement in CdTe solar cells by combining a ZnO buffer layer and a solution back contact

Conventional CdTe solar cells have a CdS window layer, in which an absorption loss of photons with more than 2.4 eV occurs through the CdS layer. A thinner CdS layer was applied to enhance light transmission and a ZnO buffer layer with a band gap of 3.3 eV was introduced to suppress shunting through the thinner CdS window layer. A 100-nm thick ZnO layer sputter-deposited at 300 °C had uniform coverage on a transparent conductive oxide (TCO) after a subsequent high-temperature process. The ZnO layer was effective in preventing shunting through the CdS window layer so that the open-circuit voltage and fill factor of the CdTe solar cells were recovered and the short-circuit current was enhanced over that of the conventional CdTe solar cell. In the ZnO/CdS/CdTe configuration, the short-circuit current was further improved throughout the visible wavelength region by replacing the Cu-metal contact with a Cu solution contact. As a result the short-circuit current from 21.7 to 26.1 mA/cm² and the conversion efficiency of the CdTe solar cell increased from 12 to 15% without antireflective coating. Our result indicates that the Cu solution back contact is a critical factor for achieving a higher cell efficiency in addition to ZnO buffer layer.     

Performance improvement of MEH-PPV:PCBM solar cells using bathocuproine and bathophenanthroline as the buffer layers

In this work, bathocuproine (BCP) and bathophenanthroline (Bphen), commonly used in small-molecule organic solar cells (OSCs), are adopted as the buffer layers to improve the performance of the polymer solar cells (PSCs) based on poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV): [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojunction. By inserting BCP or Bphen between the active layer and the top cathode, all the performance parameters are dramatically improved. The power conversion efficiency is increased by about 70% and 120% with 5-nm BCP and 12-nm Bphen layers, respectively, when compared with that of the devices without any buffer layer. The performance enhancement is attributed to BCP or Bphen (i) increasing the optical field, and hence the absorption in the active layer, (ii) effectively blocking the excitons generated in MEH-PPV from quenching at organic/aluminum (Al) interface due to the large band-gap of BCP or Bphen, which results in a significant reduction in series resistance (Rs), and (iii) preventing damage to the active layer during the metal deposition. Compared with the traditional device using LiF as the buffer layer, the BCP-based devices show a comparable efficiency, while the Bphen-based devices show a much larger efficiency. This is due to the higher electron mobility in Bphen than that in BCP, which facilitates the electron transport and extraction through the buffer layer to the cathode.     

Stable organic solar cells employing MoO3-doped copper phthalocyanine as buffer layer

A stable organic solar cell with structure of ITO/buffer/donor/acceptor/cathode is presented. A thin layer (5 nm) of MoO₃-doped CuPc is adopted as the buffer in CuPc/C₆₀ organic heterojunction photovoltaic (PV) solar cells, resulting in two times longer lifetime. The surface morphology of buffer layer plays a decisive role in improving the stability.     

阴极功函数和激子产生率对肖特基接触单层有机太阳能电池开路电压的影响研究

运用数值方法系统研究了阴极功函数,激子产生率和温度对肖特基接触单层有机太阳能电池开路电压的影响,分析了开路电压条件下有机太阳能电池有机层内载流子和电场的分布.结果表明在阳极功函数一定时开路电压随着阴极功函数（W_c）的降低而增大,当W_c接近有机材料的最低未被占据分子轨道（LUMO）能级时开路电压不再增大而达到一个饱和值,饱和开路电压随激子产生率的提高而增大;对于给定的阳极和阴极功函数,开路电压随激子产生率的提高而增大并在激子产生率达到一 关键词： 开路电压 温度 阴极功函数 单层有机太阳能电池     

Low‐temperature atomic layer deposition of MoOx for silicon heterojunction solar cells

The preparation of high‐quality molybdenum oxide (MoO_x) is demonstrated by plasma‐enhanced atomic layer deposition (ALD) at substrate temperatures down to 50 °C. The films are amorphous, slightly substoichiometric with respect to MoO₃, and free of other elements apart from hydrogen (&11 at%). The films have a high transparency in the visible region and their compatibility with a‐Si:H passivation schemes is demonstrated. It is discussed that these aspects, in conjunction with the low processing temperature and the ability to deposit very thin conformal films, make this ALD process promising for the future application of MoO_x in hole‐selective contacts for silicon heterojunction solar cells. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

复合阴极缓冲层Alq_3∶CsF对CuPc/C_(60)电池性能的影响

通过Alq_3∶CsF复合阴极缓冲层来优化CuPc/C_(60)有机小分子太阳能电池的性能。当Alq_3∶CsF厚度为5nm,CsF的掺杂比例为4%时,加入复合阴极缓冲层器件较Alq_3阴极缓冲层器件的能量转化效率提高了49%,到达0.76%,并且在室温、大气的条件下,器件的稳定性也得到了保持,与未加阴极缓冲层的器件相比,半衰期提高了6倍,达到9.8h。通过紫外-可见吸收、外量子效率和单载流子传输器件等研究了器件效率改善的主要原因是掺入CsF后,调节界面能级,改善了Alq_3的电子传输特性,提高了器件的短路电流和填充因子。比较分析复合阴极缓冲层器件于空气中放置不同的时间的电流电压曲线,表明Alq_3∶CsF可以保持Alq_3的良好稳定性,可以很好地阻挡氧气与水分的扩散,提高器件的寿命。     

Cu_2O/ZnO氧化物异质结太阳电池的研究进展

介绍了近年来低成本Cu_2O/ZnO氧化物异质结太阳电池方面的研究进展.应用于光伏器件的吸收层材料Cu_2O是直接带隙半导体材料,天然呈现p型;其原材料丰富,且对环境友好.Cu_2O/ZnO异质结太阳电池结构主要有平面结构和纳米线/纳米棒结构.纳米结构的Cu_2O太阳电池提高了器件的电荷收集作用;通过热氧化Cu片技术获得的具有大晶粒尺寸平面结构Cu_2O吸收层在Cu_2O/ZnO太阳电池应用中展现出了高质量特性.界面缓冲层(如i-ZnO,a-ZTO,Ga_2O_3等)和背表面电场(如p~+-Cu_2O层等)可有效地提高界面处能级匹配和增强载流子输运.10 nm厚度的Ga_2O_3提供了近理想的导带失配,减少了界面复合;Ga_2O_3非常适合作为界面层,其能够有效地提高Cu_2O基太阳电池的开路电压V_(oc)(可达到1.2 V)和光电转换效率.p~+-Cu_2O(如Cu_2O:N和Cu_2O:Na)能够减少器件中背接触电阻和形成电子反射的背表面电场(抑制电子在界面处复合).利用p型Na掺杂Cu_2O(Cu_2O:Na)作为吸收层和Zn_(1-x)Ge_x-O作为n型缓冲层,Cu_2O异质结太阳电池(器件结构:MgF_2/ZnO:Al/Zn_(0.38)Ge_(0.62)-O/Cu_2O:Na)光电转换效率达8.1%.氧化物异质结太阳电池在光伏领域展现出极大的发展潜力.