The effect of DIO additive on performance improvement of polymer solar cells

A series of polymer solar cells （PSCs） based on poly （diketopyrrolopyrrole-terthiophene） （PDPP3T） and [6,6]-phenyl-C71-butyric acid methyl ester （PC71BM） as active layer were fabricated to investigate the effect of 1,8- diiodooctane （DIO） on the performance of PSCs. The power conversion efficiency （PCE） of PSCs was increased from 3.77 % to 4.37 % for the cells with DIO additive. The underlying reason may be attributed to that DIO additive could make PC71BM more dispersive in the active layer, forming a better bicontinuous interpenetrating network for excition dissociation and charge carrier transport. There- fore, the short circuit current density （Jsc） and fill factor （FF） was increased from 8.25 to 9.18 mA/cm2 and from 67.2 % to 70.0 % for the PSCs with DIO additive compared with PSCs without DIO additive.     

活性层混合溶剂的选择对高分子太阳能电池性能的影响

高分子有机太阳能电池因为其简单的制作工艺和轻便稳定的特性而引起人们的广泛研究。控制活性层的形貌对于提高有机太阳能电池的光电性能有着至关重要的意义。使用两种不同的混合溶剂(氯仿/1,8-二碘代辛烷和氯苯/1,8-二碘代辛烷)来制备PTB7-Th:PC_(70)BM活性层。发现使用氯苯/1,8-二碘代辛烷能使活性层获得更好的相分离效果,从而有利于光的吸收和电荷的分离。相对于氯仿/1,8-二碘代辛烷,使用氯苯/1,8-二碘代辛烷的太阳能电池的光电转化效率从7.21%大幅提高到了8.86%。这主要来自短路电流密度(从15.1 mA/cm~(-2)提高至16.7 mA/cm~2)和填充因子(从61.2%提高至66.3%)的提高。结果表明使用氯苯/1,8-二碘代辛烷作为混合溶剂有利于制备高性能的基于PTB7-Th:PC_(70)BM的有机太阳能电池。     

基于双阳极界面修饰层有机太阳能电池研究

为提高有机太阳能电池的能量转换效率,提出一种基于双阳极界面修饰层的有机太阳能电池优化方案。该方法主要采用四氟乙烯( PTFE: Polytetrafluoroethylene) 和五氧化二钒( V2O5: Vanadiumpentoxide) 作为阳极界面修饰层,制备了器件结构为ITO/PTFE/V2O5 /PCDTBT ∶ PC71 BM/LiF/Al 的有机太阳能电池。测试结果表明,引入PTFE/V2O5双阳极界面修饰层的有机太阳能电池的能量转化效率最高可达6． 52%。相比于V2O5单阳极界面修饰层器件效率提高了11． 5%。测试结果证明双阳极界面修饰层的功函数与PCDTBT 材料的HOMO 能级更加匹配,有利于空穴的传输和提取。同时PTFE/V2O5 改善了氧化铟锡( ITO) 表面形貌,减少界面缺陷,抑制了界面处载流子的复合。     

杂化太阳能电池活性层对光电转换效率的影响

从活性层的材料组成、结构与成分组成、制备以及光电性能优化等方面综述了当前的研究现状。指出活性层对太阳光的吸收效率、电池内激子分离效率和载流子传输效率是影响电池光电转换效率的三大因素,通过对活性层的组成材料、结构与成分组成恰当选择,结合活性层的制备及光电性能优化可有效提高电池光电转换效率。并展望了杂化太阳能电池的今后发展趋势。     

Luminescent and photovoltaic properties of poly（9,9-dioctylfluorene- co-bithiophene） in organic electronic devices

We studied the luminescent and photovoltaic properties of poly(9,9-dioctylfluorene-co-bithiophene)(F8T2) based on ITO/PEDOT:PSS/F8T2/Bphen/LiF(0 or 1 nm)/Al and ITO/PEDOT:PSS/F8T2:PCBM/Bphen/Al.A stable and bright yellow emission was obtained from polymer F8T2,and the electroluminescence power reached 45 ?W at a 15 V driving voltage.Polymer F8T2 shows a broad absorption band from 400 to 500 nm,and has a shorter absorption edge at about 560 nm compared to that of the typical electron donor P3HT(650 nm).The photoluminescence quenching of F8T2 occurs with only a small fraction of blended PCBM due to the effective exciton dissociation at the interface between F8T2 and PCBM.Polymer solar cells(PSCs) using F8T2:PCBM as the active layer show a low power conversion efficiency(PCE) of 0.10% with an open circuit voltage(Voc) of 0.91 V and short circuit current density(Jsc) of 0.23 mA/cm2.The PSCs using F8T2:P3HT:PCBM as the active layer have a Voc of 0.85 V and Jsc of 3.02 mA/cm2,improving the PCE by about 0.90%.We attribute the improved cell performance to the higher number of photons harvested by P3HT molecules.     

双重优化对基于P3HT:PCBM有机太阳能电池效率的提高

有效提高太阳能电池对光的吸收效率是提高太阳能电池能量转换效率的重要因素.在以poly(3-hexylthiophene)(P3HT)为电子给体材料,[6,6]-phenyl C60-butyric acid methyl eater(PCBM)为电子受体材料的有机太阳能电池中,Poly-(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)与活性层之间插入不同厚度的P3HT层,并在P3HT层最佳厚度的基础上,进一步在活性层中掺杂不同比例的Ag纳米粒子,双重优化了电池器件.当插入45 nm的P3HT层及掺杂质量比为5%的Ag纳米粒子时活性层薄膜的形貌及内部结构得到了改善,电池对光的吸收,及外量子效率得到了显著地提高,并出现红移现象.在25°C,光强为100 mW/cm2的条件下测量其短路电流密度JSC为11.21 mA/cm2,能量转化效率PCE为3.79%.     

Flexible dye-sensitized solar cell based on PCBM/P3HT heterojunction

Using blend heterojunction consisting of C60 derivatives [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and poly(3-hexylthiophene) (P3HT) as charge carrier transferring medium to replace I3–/I– redox electrolyte,a novel flexible dye-sensitized solar cell (DSSC) is fabricated.The characterization of infrared spectra and ultraviolet-visible spectra shows that the PCBM/P3HT heterojunction has not only the absorption in ultraviolet light for PCBM,but also the absorption in visible and near infrared light for P3HT,which widens the photoelectric response range for DSSC.The influence of PCBM/P3HT mass ratio on the performance of the solar cell is discussed.Under 100 mW cm–2 (AM 1.5) simulated solar irradiation,the flexible solar cell achieves a lightto-electric energy conversion efficiency of 1.43%,open circuit voltage of 0.87 V,short circuit current density of 3.0 mA cm–2 and fill factor of 0.54.     

Sb2S3:P3HT共混物改善TiO2纳米棒阵列钙钛矿太阳电池的性能

为解决钙钛矿太阳电池中MAPbI₃的不稳定性问题,提高电池性能,对以TiO₂纳米棒阵列作为电子传输层、Sb₂S₃:P3HT共混物作为钙钛矿MAPbI₃修饰层的太阳电池进行了研究。首先,以SbCl₃作为锑源,Na₂S₂O₃作为硫源,采用溶剂热法制备合适尺寸的Sb₂S₃纳米球;其次,通过超声分散法将Sb₂S₃与P3HT在氯苯溶液中共混得到Sb₂S₃:P3HT共混物,将其旋涂于沉积了MAPbI₃薄膜的TiO₂纳米棒阵列上,形成FTO/TiO₂NR/MAPbI₃/Sb₂S₃:P3HT复合膜,制备成TiO₂纳米棒阵列MAPbI₃/Sb₂S₃:P3HT太阳电池;最后,采用SEM,XRD,J-V曲线和紫外可见吸收光谱等方法进行表征和测试。结果表明,制备的结构为FTO/TiO₂NR/MAPbI₃/Sb₂S₃:P3HT/Spiro-OMeTAD/Ag的太阳电池,能量转换效率（PCE）最高达到了14.73％,与未采用Sb₂S₃:[JP]P3HT共混物修饰的TiO₂纳米棒阵列MAPbI₃太阳电池相比,能量转换效率得到了明显提升。因此,Sb₂S₃:P3HT共混物能避免出现钙钛矿MAPbI₃被氧化的不稳定性问题,可有效提高TiO₂纳米棒阵列MAPbI₃太阳电池的性能。     

退火对薄膜P3HT-PCBM太阳能电池的光电性能影响

以吩聚噻(P3HT)/C60的衍生物(PCBM)为活性层的太阳能电池为研究对象,研究薄膜退火对电池光电性能的影响.结果表明,退火能够提高材料的结晶度,增加光的透射率,降低反射率.在140℃温度下退火,该器件光电转化效率最大.     

P3HT和Spiro-OMeTAD共混物作为光活性层的杂化太阳电池性能

为降低电荷复合率,提高杂化太阳电池的性能,将P3HT与Spiro-OMeTAD共混后的混合物作为光活性层和空穴传输层,旋涂在Sb_2S_3纳米粒子敏化的TiO_2纳米棒(TiO_2NR/Sb_2S_3)复合膜上,制备成杂化太阳电池。通过SEM、紫外可见吸收光谱、XRD、电化学阻抗图谱、稳态荧光光谱、J-V曲线等手段,对杂化太阳电池的微观结构、光电转换特性进行了表征和测试。结果表明:P3HT与Spiro-OMeTAD共混物比例为15 mg/1 mL时,得到结构为FTO/TiO_2NR/Sb_2S_3/P3HT:Spiro-OMeTAD/Ag杂化太阳电池的电荷负荷率低,电子生命长,能量转换效率达到了4.57%。所制备的杂化太阳电池性能优良,具有良好的应用前景。     

Nanoscale structural and electronic evolution for increased efficiency in polymer solar cells monitored by electric scanning probe microscopy

Control of blend morphology at multi-scale is critical for optimizing the power conversion efficiency （PCE） of plastic solar cells. To better understand the physics of photoactive layer in the organic photovoltaic devices, it is necessary to gain understanding of morphol- ogy and the corresponding electronic property. Herein we report the correlation between nanoscale structural, electric properties of bulk heterojunction （BHJ） solar cells and the annealing-induced PCE change. We demonstrate that the PCE of BHJ solar cells are dramatically improved （from 1.3 % to 4.6 %） by thermal annealing, which results from P3HT crystalline stacking and the PCBM aggregation for interpenetrated network. The similar trend for annealing- induced photovoltage and PCE evolution present as an initial increase followed by a decrease with the annealing time and temperature. The surface roughness increase slowly and then abruptly after the same inflection points observed for photovoltage and PCE. The phase images in electric force microscopy indicate the optimized P3HT and PCBM crystallization for interpenetrating network formation considering the spectroscopic results as well. From the correlation between surface photovoltage, blend morphology, and PCE, we propose a model to illustrate the film structure and its evolution under different annealing conditions. This work would benefit the better design and optimization of the morphology and local electric proper- ties of solar cell active layers for improved PCE.     

Fluorescence and sensitization performance of phenylene-vinylene-substituted polythiophene

A new kind of polythiophene derivative, Poly(3-{2-[4-(2-ethylhexyloxy)-phenyl]-vinyl}-2,2′-bithiophene) (PTh), was applied in dye-sensitized solar cell to extend the light response of nanocrystalline TiO2 electrode. UV-vis absorption and fluorescence spectra were employed to investigate the interaction of PTh with nanocrystalline TiO2. The absorption coefficient of the PTh was high in visible part of spec- trum, and the fluorescence emission of the PTh can be efficiently quenched by TiO2 nanoparticles ow- i...     

Self-assembly of N-3-γ-pyridyl Aza[60]fulleroid on Au(111)

Self-assembled monolayers of novel C₆₀ derivative, N-3-γ-pyridyl Aza[60]fulleroid (C₆₀Py), on Au(111) were studied by a scanning tunneling microscope under ultrahigh vacuum (UHV). C₆₀Py molecules were assembled on Au (111) via pyridyl nitrogen-Au interaction. The sole assembly of C₆₀Py molecules on Au (111) only exhibited randoml aggregation of C₆₀Py even the films were annealed at 50 and 105°C. By co-assembling with benzyl mercaptan (BM), the C₆₀PyBM films showed highly dense aggregation, but C₆₀Py assemblies still had disordered structure. After the co-assembled C₆₀Py-BM films were annealed at 50°C, BM molecules were partially desorbed, but the assembly of C₆₀Py remained without obvious change. After the co-assembled C₆₀Py-BM films were further annealed at 105°C, the C₆₀Py monolayers with ordered structure were obtained, while the BM molecules were nearly thoroughly desorbed from the surface. Here, the BM molecules play a key role as a surfactant in the formation of the ordered C₆₀Py monolayer.     

基于苯并三噻吩共聚物/富勒烯衍生物的聚合物太阳能电池

以苯并三噻吩共聚物(BTT-BTz)为给体材料,具有不同能级结构的富勒烯衍生物为受体材料,通过共混方式制备光敏薄膜,并研究受体材料的能级结构对光伏器件开路电压(Voc)、短路电流(Jsc)、填充因子(FF)和电池效率(PCE)的影响.结果表明:当IC60BA为电子受体材料时,器件的Voc=1.06V,但Jsc较低,使得PCE仅为1.49%;当PC60BM和PC70BM为受体材料时,Voc分别为0.86V和0.81V,但Jsc较高,使得PCE分别为3.22%和5.06%.     

基于ZnO材料的有机-无机杂化太阳电池的光伏性能优化

有机-无机杂化太阳电池是一种由提供电子的有机聚合物和接受电子的无机半导体构成的新型电池,常用的无机半导体材料有纳米氧化锌（ZnO）、二氧化钛（TiO₂）、硫化镉（CdS）等。杂化太阳电池在研究过程中存在一些问题,如电池中电子传输效率差、太阳能利用率低、无机半导体和有机聚合物之间化学不兼容以及由此导致的光电转换效率低等。围绕这些问题,针对以ZnO半导体材料为电子受体的太阳电池,从电子受体材料形貌、电子给体材料种类以及添加不同修饰层等方面论述了电池光伏性能的优化方法,对该电池的未来发展趋势进行了展望。电池性能的优化,为低成本、高效率应用该类杂化太阳电池带来了希望。     

Array of single crystalline anatase TiO2 nanotubes with significant enhancement of photoresponse

Anatase TiO₂ nanotubes array (ATONA) has attracted tremendous attention owing to its promising applications in solar cells, water splitting and organic pollutants photocatalytic degradation. However, the activity of ATONAs was greatly suppressed by the grain boundaries existed in the tube walls, which acted as carrier scattering and recombination centers. Herein, we report a novel strategy to prepare array of single crystalline anatase TiO₂ nanotubes (SC-ATONAs) with significant enhancement of the photocatalytic activity and UV photo response performance compared to the polycrystalline counterparts. The growth of SC-ATONAs was achieved by establishing a crystallization temperature gradient along the tube wall, which ensured the crystallization started from the nucleation of a single nucleus at the bottom of amorphous TiO₂ nanotubes prepared by Ti anodization. These findings pave the way to prepare single-crystalline nanotubes with superior performance for other materials.     

One-pot synthesis of Sb-Fe-carbon-fiber composites with in situ catalytic growth of carbon fibers

A Sb-Fe-carbon-fiber (CF) composite was prepared by a chemical vapor deposition (CVD) method with in situ growth of CFs using Sb₂O₃/Fe₂O₃ as the precursor and acetylene (C₂H₂) as the carbon source. The Sb-Fe-CF composite was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), and its electrochemical performance was investigated by galvanostatic charge-discharge cycling and electrochemical impedance spectroscopy. The Sb-Fe-CF composite shows a better cycling stability than the Sb-amorphous-carbon composite prepared by the same CVD method but using Sb₂O₃ as the precursor. Improvements in cycling stability of the Sb-Fe-CF composite can be attributed to the formation of three-dimensional network structure by CFs, which can connect Sb particles firmly. In addition, the CF layer can buffer the volume change effectively.     

Optimization of polymer electrolytes for quasi-solidstate dye-sensitized solar cells

The dye-sensitized nanocrystalline TiO2 thin filmsolar cells (DSSCs) have attracted much attention since1990s[1— , due to their high light to electrical energy 4]conversion efficiency. So far, many studies have beenmade on the use of liquid electrolytes such as acetonitrile,3-methoxypropionitrile and a mixture of ethylene/pro-pylene carbonate (EC/PC) containing I? /I3 redox cou-?ple. A light to electrical energy conversion efficiency of7%— 12% has been obtained for DSSC using liquid e…     

Combined effects of solar UV radiation and CO2-induced seawater acidification on photosynthetic carbon fixation of phytoplankton assemblages in the South China Sea

We carried out short term pCO₂/pH perturbation experiments in the coastal waters of the South China Sea to evaluate the combined effects of seawater acidification (low pH/high pCO₂) and solar UV radiation (UVR, 280–400 nm) on photosynthetic carbon fixation of phytoplankton assemblages. Under photosynthetically active radiation (PAR) alone treatments, reduced pCO² (190 ppmv) with increased pH resulted in a significant decrease in the photosynthetic carbon fixation rate (about 23%), while enriched pCO₂ (700 ppmv) with lowered pH had no significant effect on the photosynthetic performance compared to the ambient level. The apparent photosynthetic efficiency decreased under the reduced pCO₂ level, probably due to C-limitation as well as energy being diverged for up-regulation of carbon concentrating mechanisms (CCMs). In the presence of UVR, both UV-A and UV-B caused photosynthetic inhibition, though UV-A appeared to enhance the photosynthetic efficiency under lower PAR levels. UV-B caused less inhibition of photosynthesis under the reduced pCO₂ level, probably because of its contribution to the inorganic carbon (Ci)-acquisition processes. Under the seawater acidification conditions (enriched pCO₂), both UV-A and UV-B reduced the photosynthetic carbon fixation to higher extents compared to the ambient pCO₂ conditions. We conclude that solar UV and seawater acidification could synergistically inhibit photosynthesis.     

不同溶剂溶解聚合物光伏特性的研究

采用聚3-己基噻吩（P3HT）溶于不同溶剂作为光敏层制备光伏器件,器件结构为：ITO/PEDOT：PSS/P3HT/Al.我们分析了聚3-己基噻吩（P3HT）溶于不同溶剂制成的光敏层薄膜,并对光敏层薄膜的形貌通过原子力显微镜（AFM）进行了表征.研究发现,P3HT溶于氯苯的薄膜形貌最优,光伏特性最好,短路电流、开路电压都比溶于氯仿和二甲苯的高.