Enhanced electron lifetime on nitrogen-doped TiO2 films for dye-sensitized solar cells

Nitrogen-doped TiO2 crystallites were prepared via the hydrolysis of TiCl4 using an ammonia medium in an aqueous solution for DSSC photoelectrodes. The optimized photoelectrode for the DSSC was prepared with 9.4 nm sized N-doped TiO2 crystal (BET; 200 m2/g), which provides a relatively high short circuit current and energy conversion efficiency in the DSSC. The photovoltaic performance of the N-doped TiO2 electrode was confirmed using incident photon-to-current efficient spectra, impedance analyses, and Bode-phase plots which proved that the N-doped TiO2 electrode has a significantly enhanced electron lifetime compared with that of the P25 electrode.     

染料敏化太阳能电池MO／TiO2复合薄膜的制备与表征

用溶胶-凝胶法结合旋转镀膜法制备致密TiO2薄膜，采用丝网印刷技术制备多孔TiO2薄膜，采用液相沉积法制备ZnO／Ti02、MgO／TiO2复合薄膜。用x射线能谱仪、原子力显微镜、紫外-可见分光光度计对复合薄膜的化学组分、表面形貌、吸光性能等进行分析；组装电池，测定了电池性能。结果表明：ZnO／TiO2、MgO／TiO2复合薄膜具有较好的光电性能，染料敏化太阳能电池的短路电流、开路电压、填充因子、光电转换效率均得到提高。     

TiO2 paste formulation for crack-free mesoporous nanocrystalline film of dye-sensitized solar cells

Using a doctor-blade method, a highly viscous titanium dioxide (TiO2) paste was deposited on a glass substrate coated with fluorine doped tin oxide (FTO). The paste was mainly composed of commercially available TiO2 nanoparticles (P25) and hydroxypropyl cellulose (HPC) as organic filler. Varying the content of HPC in the TiO2 paste changed the physical properties of the mesoporous TiO2 layer, particularly its porosity and surface area. From the quantification of dyes on Ti2, layer and the electrochemical impedance spectroscopy (EIS) study of the dye-sensitized solar cells (DSSCs), the surface area of the TiO2 film was found to have decreased. This came with the increase of HPC content while the porosity of the film increased, consistent with the concurrent decrease of short-circuit current density (Jsc) and efficiency (eta). The increased porosity greatly affected the electron transport through the TiO2 film by decreasing the coordination number of the TiO2 particles resulting to a decrease of the electron diffusion coefficient.     

TiO2纳米管阵列电极染料敏化太阳能电池

采用电化学阳极氧化法在纯钛片表面制备了高度有序的TiO2纳米管阵列。利用SEM、XRD分别对TiO2纳米管阵列的形貌、晶型进行了表征,并通过线性扫描伏安法对N719染料敏化纳米管阵列电极的光电性能进行了研究。实验结果表明,纳米管阵列的管径和长度随着阳极氧化电压的升高和氧化时间的延长都分别相应增加。同时还发现,通过450℃热处理的TiO2纳米管阵列,具有较好的锐钛矿晶型结构,其光电转化效率为2.1%。     

Hierarchical structured TiO2 photoanodes for dye-sensitized solar cells

A novel approach has been developed to fabricate hills-like hierarchical structured TiO2 photoanodes for dye-sensitized solar cells (DSSCs). The appropriately aggregated TiO2 clusters in the photoanode layer could cause stronger light scattering and higher dye loading that increases the efficiency of photovoltaic device. For detailed light-harvesting study, different molecular weights of polyvinyl alcohol (PVA) were used as binders for TiO2 nanoparticles (P-25 Degussa) aggregation. A series of TiO2 films with dissimilar morphology, the reflection of TiO2 films, absorbance of attached dye, amount of dye loading, and performance of fabricated DSSC devices, were measured and investigated. An optimized device had energy conversion efficiency of 4.47% having a higher dye loading and good light harvesting, achieving a 23% increase of short-circuit current J(sc) in DSSCs.     

磁控溅射制备染料敏化太阳能电池氮掺杂碳膜对电极

采用双极脉冲磁控溅射法制备氮掺杂碳膜并作为对电极应用在染料敏化太阳能电池(DSSC)中。研究了氮掺杂对碳膜的结构与性能的影响。用X射线光电子能谱(XPS)对氮掺杂碳膜进行薄膜表面元素分析,用四探针测试仪对氮掺杂碳膜的方块电阻进行测试,用扫描电镜对氮掺杂碳膜表面形貌进行分析。组装电池,用太阳光模拟器测试电池的光电转化率。研究结果表明,经过氮掺杂的碳膜,表面形貌致密,当N2的体积分数为30%时,薄膜中N元素含量为15.21%,薄膜的方块电阻为9.4Ω/□,电池的光电转化率为1.16%。     

Holographically defined TiO2 electrodes for dye-sensitized solar cells

We describe a multibeam interference lithography for creating 3D polymeric porous structures. The coating of a TiO(2) shell and subsequent removal of the template produce holographically defined TiO(2) (h-TiO(2)) electrodes. We analyze the morphological features of the h-TiO(2) electrodes and consider their applicability to dye-sensitized solar cells (DSSCs). Specifically, the performance of the h-TiO(2) electrode was evaluated by comparison with a macroporous TiO(2) electrode produced from colloidal crystals. The h-TiO(2) structure possesses a larger specific area than the inverted colloidal crystals because of a bicontinuous air network with the TiO(2) shell. Consequently, the h-TiO(2) electrode can produce a 30% higher photogenerated electron current.     

染料敏化TiO2纳米晶太阳能电池的研究

通过改变TiO2 膜热处理温度来研究染料RuL2 (SCN ) 2 敏化TiO2 纳米晶太阳能电池光电性能。得热处理温度对TiO2 膜的质量有很大的影响。染料RuL2 (SCN) 2 的吸收光谱表明 ,染料RuL2 (SCN) 2 在可见光有很宽且强的吸收 ,是一种很理想的敏化剂。用XRD和UV -Vis等手段分别表征了TiO2 膜和染料。     

TiO2-grafted multi-walled carbon nanotubes for dye-sensitized solar cells

Dye-Sensitized Solar Cells (DSSCs) comprised of TiO2 porous films with multi-walled carbon nanotubes (MWNT) were prepared at low temperature (150 degrees C). MWNT were incorporated to facilitate the fast electron transport resulting from metallic properties of carbon nanotubes. In order to enhance the effect of MWNT incorporation, TiO2-grafted MWNT (TiO2-MWNT) was synthesized which can increase the electron transport rate further due to proximity of TiO2 to MWNT The presence of TiO2 nanoparticles on the surface of MWNT was confirmed by electron microscopy and energy dispersive X-ray spectroscopy. As in the DSSCs prepared through high temperature sintering of photoanodes, the maximum content of MWNT incorporated into TiO2 was limited to 0.01 wt% relative to TiO2. TiO2 photoanodes including TiO2-grafted MWNT (TiO2-MWNT/P25) enhanced the cell efficiencies by ca. 28% and 14%, relative to TiO2 photoanodes without and with MWNT respectively, reaching the efficiency of 5.0%. Electrochemical impedance spectroscopy (EIS) was utilized to examine the effect of incorporation of TiO2 nanoparticles grafted to MWNT on the cell performance.     

Enhanced electron transport in mesoporous TiO2 films modified by sol-gel necking for dye-sensitized solar cells

Mesoporous TiO2 films modified via sol-gel necking were fabricated by dispersing Ti tetra-isopropoxide (TTIP; 8 to 16 wt% over TiO2) with TiO2 nanoparticles in isopropyl alcohol. The dye-sensitized solar cells (DSSCs) with 13 wt% TTIP-modified TiO2 film exhibited significantly improved overall energy conversion efficiency, despite having less adsorbed dye when compared with DSSCs with untreated and TiCl4 post-treated TiO2 films. The improvement can be attributed to the sol-gel necking (or interconnection) between the nanoparticles which leads to a much faster electron transport and a suppression of the recombination (or back electron transfer) between the TiO2 and electrolyte.     

介孔TiO2微球水热法合成及在染料敏化太阳能电池中的应用

以Ti(SO4)2为钛源,采用尿素辅助水热法合成了介孔TiO2微球,利用XRD、FESEM和比表面积分析仪对样品的晶型、形貌和比表面积进行分析,探讨了尿素加入量对TiO2微球的颗粒尺寸、比表面积、孔径和孔容的影响。采用刮涂法,用所合成的介孔TiO2微球制备了染料敏化太阳能电池(DSSC)的光阳极,结果表明,尿素用量为1.2g合成的介孔TiO2微球所组装的电池在模拟太阳光的照射下(100mW/cm2,AM1.5),光电转换效率为6.2%,明显高于商用P25纳晶所组装的电池光电转换效率(4.24%)。     

染料敏化太阳能电池的TiO2光电极的制备及优化

讨论了染料敏化太阳能电池的TiO2光电极制备与优化工艺过程,这主要包括TiO2薄膜厚度的优化,利用TiCl4处理导电玻璃以及添加大粒子散射层.研究结果表明,当TiO2光阳极厚度为11μm时,电池的转换效率最高.添加TiO2大粒子散射层后,增强了光阳极对光的吸收,当大粒子散射层为4.4μm时,电池的光电性能最好.对TiO...     

TiO2 coated urchin-like SnO2 microspheres for efficient dye-sensitized solar cells

Urchin-like SnO2 microspheres have been grown for use as photoanodes in dye-sensitized solar cells （DSSCs）. We observed that a thin layer coating of TiO2 on urchin-like SnO2 microsphere photoanodes greatly enhanced dye loading capability and light scattering ability, and achieved comparable solar cell per- formance even at half the thickness of a typical nanocrystalline TiO2 photoanode. In addition, this photoanode only required attaching -55% of the amount of dye for efficient light harvesting compared to one based on nanocrystalline TiO2. Longer decay of transient photovoltage and higher charge recombination resistance evidenced from electrochemical impedance spectroscopy of the devices based on TiO2 coated urchin-like SnO2 revealed slower recombination rates of electrons as a result of the thin blocking layer of TiO2 coated on urchin- like SnO2. TiO2 coated urchin-like SnO2 showed the highest value （76.1 ms） of electron lifetime （＇r） compared to 2.4 ms for bare urchin-like SnO2 and 14.9 ms for nanocrystalline TiO2. TiO2 coated SnO2 showed greatly enhanced open circuit voltage （Voc）, short-circuit current density （Jsc） and fill factor （FF） leading to a four-fold increase in efficiency increase compared to bare SnO2. Although TiO2 coated urchin-like SnO2 showed slightly lower cell efficiency than nanocrystalline TiO2, it only used a half thickness of photoanode and saved -45% of the amount of dye for efficient light harvesting compared to normal nanocrystalline TiO2.     

Influence of TiO2 nanofiber additives for high efficient dye-sensitized solar cells

TiO2 nanofibers were prepared from a mixture of titanium-tetra-isopropoxide and poly vinyl pyrrolidone by applying the electrospinning method. The samples were characterized by XRD, FE-SEM, TEM and BET analyses. The diameter of electrospun TiO2 nanofibers is in the range of 70 approximately 160 nm. To improve the short-circuit photocurrent, we added the TiO2 nanofibers in the TiO2 electrode of dye-sensitized solar cells (DSSCs). TiO2 nanofibers added in DSSCs can make up to 20% more conversion energy than the conventional DSSC with only TiO2 films only.     

Hydrochloric acid treatment of TiO2 electrode for quasi-solid-state dye-sensitized solar cells

Quasi-solid-state dye-sensitized solar cell was fabricated by sandwiched polymer electrolyte containing liquid electrolytes between the dye-sensitized TiO2 electrode and a Pt electrode. The influence of hydrochloric acid treatment of TiO2 photoelectrode on the photoelectronic performance was investigated. Quasi-solid-state dye-sensitized solar cell showed better photoelectronic performance when the TiO2 electrode was treated with hydrochloric acid than that without treatment. The short-circuit current density (J(sc)), the open-circuit voltage (V(oc)), and a conversion efficiency obtained for an incident light intensity of 100 mW m(-2) were 6.49 mA cm(-2), 0.76 V and 4.1%, respectively. It was found that the hydrochloric acid treatment of TiO2 electrode increased the short-circuit current density and cell efficiency.     

Mesoporous inverse opal TiO2 film as light scattering layer for dye-sensitized solar cell

The light harvesting efficiency of dye-sensitized solar cells was enhanced by using a scattering layer. Such as sphere type TiO2, inverse photonic crystal TiO2, hollow spherical TiO2. Among these materials, the TiO2 with inverse photonic crystal (IPC) structure, synthesized by self-assembly using spherical templates, has attracted much attention due to their photonic crystal characteristics and light scattering effects. However, when applied in the DSSCs, the surface area of IPC is very low that caused insufficient adsorption amount of dye molecules. In the present work, a scattering layer with mesoporous inverse photonic crystal (MIPC) TiO2 film was fabricated by the sol-gel reactions with surfactant-assisted sol-gel method using poly(methyl methacrylate) as the template and titanium (IV) isopropoxide as the TiO2 precursor. After removing the PMMA and surfactant, a highly ordered macroporous structure with mesopores were successfully obtained. The surface area and total pore volume of the MIPC were 82 m2/g and 0.31 cm3/g, respectively, which is much larger than those of the IPC. The DSSCs with the scattering layer of MIPC film exhibited 18 and 10% higher photo-conversion efficiency than those of cells only with a nano-crystalline TiO2 film and with scattering layer of IPC film. From UV-visible spectra of dye solutions, the MIPC film showed a higher amount of absorbed dye molecules than those of the reference and IPC films. Accordingly, an increase in the photo-current density through abundant adsorption of the dye, coupled with inherent light scattering ability can improve overall photo-conversion efficiency.     

柔性染料敏化太阳能电池TiO2薄膜的低温制备技术

简要介绍了柔性染料敏化太阳能电池的特点,综述了柔性染料敏化太阳能电池中TiO2纳米晶半导体薄膜光电极的低温制备技术.