Fabrication of large-scale ripples on fluorine-doped tin oxide films by femtosecond laser irradiation

The large-scale uniform self-organized ripples are fabricated on fluorine-doped tin oxide （FTO） coated glass by femtosecond laser. They can be smoothly linked in a horizontal line with the moving of XYZ stage by setting its velocity and the repetition rate of the laser. The ripple-to-ripple linking can also be realized through line-by-line scanning on a vertical level. The mechanism analysis shows that the seeding effect plays a key role in the linking of ripples.     

Mechanical and optoelectric properties of post-annealed fluorine-doped tin oxide films by ultraviolet laser irradiation

The fluorine-doped tin oxide (FTO) thin film deposited on a soda-lime glass substrate was annealed by a defocus ultraviolet (UV) laser irradiation at ambient temperature. The mechanical and optoelectric properties of FTO films annealed by using the various laser processing parameters were reported. After the FTO films were subjected to laser post-annealing, the microhardness were slightly less but the reduced modulus values were larger than that of unannealed FTO films, respectively. The average optical transmittance in the visible waveband slightly increased with increasing the laser annealing energy and scan speed. Moreover, all the sheet resistance of laser annealed films was less than that of the unannealed ones. We found that the sheet resistance decrease was obviously influenced by annealing. The suitable annealing conditions could maintain the film thickness and relief the internal stress generated in the film preparation process to improve the electrical conductivity via decreasing laser energy or increasing scan speed.     

Band offsets and electronic properties of the Ga2O3/FTO heterojunction via transfer of free-standing Ga2O3 onto FTO/glass

The determination of band offsets is crucial in the optimization of Ga₂O₃-based devices, since the band alignment types could determine the operations of devices due to the restriction of carrier transport across the heterogeneous interfaces. In this work, the band offsets of the Ga₂O₃/FTO heterojunction are studied using x-ray photoelectron spectroscopy (XPS) based on Kraut's method, which suggests a staggered type-Ⅱ alignment with a conduction band offset (ΔE_C) of 1.66 eV and a valence band offset (ΔE_V) of -2.41 eV. Furthermore, the electronic properties of the Ga₂O₃/FTO heterostructure are also measured, both in the dark and under ultraviolet (UV) illuminated conditions (254 nm UV light). Overall, this work can provide meaningful guidance for the design and construction of oxide hetero-structured devices based on wide-bandgap semiconducting Ga₂O₃.     

FTO – an Electrode Material for the Stable Electrochemical Determination of Dopamine

Dopamine and other catecholamines play a keyrole for the interaction of numerous processes in the neuronal network. Hence, numerous detection methods have been developed. Electrochemical sensor developments for catecholamines are characterized mostly by complex modification strategies in order to avoid a disturbance of the sensor signal by interfering substances. Here the application of fluorine doped tin oxide (FTO) as electrode material for dopamine detection is reported avoiding the necessity of expensive modifications and stability problems. This FTO based electrode allows the discrimination between dopamine and its precursor as well as its methylated degradation product and is not disturbed by typical interfering compounds (ascorbic acid, uric acid) and is characterized by high linearity and stability of the sensor signal for repeated measurements.     

Investigation on electrochemical analysis of ZnO nanoparticles and its performance for dye-sensitized solar cells using various natural dyes

The dye-sensitized solar cells were fabricated using five different dyes extracted from the Ixora flower, Pongame leaves, Neem leaves, Pongame leaves, and Almond fruit. ZnO nanoparticle has been prepared via the solvothermal method. The prepared samples were characterized by structural properties of XRD, FE-SEM EDAX, and HR-TEM, Optical properties of UV–Visible and FTIR studies, and Conductivity studies of EIS spectra. The effect of natural dye extract from chlorophyll and anthocyanin pigment group was investigated for the performance of J-V characterization. The efficiency of almond extract of solar cells is found to be better than that of the other four solar cells.     

导电玻璃上室温沉积钛膜及TiO2纳米管阵列的制备与表征

在掺氟的杂nO2(FTO)导电玻璃衬底上采用射频磁控溅射的方法室温沉积纯Ti薄膜, 以NH4F/甘油为电解液, 经电化学阳极氧化得到结构有序、微米级的TiO2纳米管阵列/FTO复合结构, 并通过场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)以及光电化学的方法对纳米管阵列进行了表征. 研究表明, 在氩气气压为0.5 Pa, 功率为150 W, 时间为0.5 h条件下在导电玻璃上室温沉积获得钛膜的结构为晶带T型组织, 表面均匀性好且致密度较高; 在电压为30 V下, 随着阳极氧化时间从1 h延长至3 h, 纳米管的管径从50 nm增加到75 nm, 纳米管的长度从750 nm增至1100 nm后减至800 nm, 管壁由平滑变为波纹状; 随氧化电压的升高, 纳米管管径逐渐增大, 而表面覆盖物逐渐减少, 可通过在稀的HF溶液(0.05%(w, 质量分数))中超声清洗去除; 此外, 瞬态光电流测试表明结晶的电极表现出更好的光电转换性能, 紫外光照射下能促进TiO2光生载流子有效分离, 在热处理温度为450 ℃时, 具有较高的光电化学性能.     

导电玻璃负载CuO/V_2O_5复合纳米纤维光电极的制备及光电催化性能

以聚乙烯吡咯烷酮(PVP)为高分子模板剂,乙酰丙酮钒(C_(15)H_(21)O_6V)和三水合硝酸铜[Cu(NO_3)_2·3H_2O]为原料,导电玻璃(FTO)为载体,结合溶胶-凝胶法和静电纺丝技术制备了前驱体纤维,经高温焙烧后得到分布均匀、具有纤维结构的导电玻璃负载的CuO/V_2O_5复合光电极(CuO/V_2O_5/FTO).采用热重-差热分析仪(TG-DTA)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线光电子能谱仪(XPS)等对材料的结构进行表征,以亚甲基蓝(MB)为目标降解物,探讨了合成产物的光电催化性能.结果表明,CuO与V_2O_5能有效形成异质结构,其光电催化活性均比纯V_2O_5有明显提高,并且改变CuO与V_2O_5的比例对光电催化性能有较大影响,其中n(Cu)∶n(V)=1∶1时降解效率最高,达到96%.     

Investigations on the Optical Properties of Undoped,Fluorine Doped and Antimony Doped Tin Oxide Films

Undoped, fluorine doped and antimony doped tin oxide films are prepared on quartz plates by Spray pyrolysis technique. The films grown at the optimum substrate temperature with different doping levels have been chosen for this study. Optical properties of these films are investigated in the entire UV-Visible -IR region (0.2 - 10 mikrom). The observed absorption edge lies at 3.65 eV for undoped tin oxide and on doping it shifts towards higher energies, which is due to the Moss - Burstein effect. For fluorine doping depending upon the fluorine concentration, the absorption edge lies in the range 3.9 - 4.14 eV and for antimony doping it lies in the range 3.82 - 4.1 eV. In the undoped tin oxide films the direct allowed transition occurs at 4.02 eV and indirect allowed transition occurs at 2.43 eV, whereas for fluorine doped tin oxide and antimony doped tin oxide films, the direct allowed transitions occur in the range 4.18 - 4.28 and 4.13 - 4.22 eV respectively and the indirect allowed transitions occur in the range 2.63 - 2.73 and 2.54 - 2.65 eV respectively. Optical properties near the plasma edge have been analyzed using Drude's theory. The dependence of effective mass on carrier concentration has been explained on the basis of nonparabolicity of the conduction band. The shift in the fermi energy, calculated on the basis of energy dependent effective mass, is consistent with the measured shift in the absorption edge.     

Effect of fluorine doping on highly transparent conductive spray deposited nanocrystalline tin oxide thin films

The undoped and fluorine doped thin films are synthesized by using cost-effective spray pyrolysis technique. The dependence of optical, structural and electrical properties of SnO₂ films, on the concentration of fluorine is reported. Optical absorption, X-ray diffraction, scanning electron microscope (SEM) and Hall effect studies have been performed on SnO₂:F (FTO) films coated on glass substrates. The film thickness varies from 800 to 1572 nm. X-ray diffraction pattern reveals the presence of cassiterite structure with (2 0 0) preferential orientation for FTO films. The crystallite size varies from 35 to 66 nm. SEM and AFM study reveals the surface of FTO to be made of nanocrystalline particles. The electrical study reveals that the films are degenerate and exhibit n-type electrical conductivity. The 20 wt% F doped film has a minimum resistivity of 3.8 × 10⁻⁴ Ω cm, carrier density of 24.9 × 10²⁰ cm⁻³ and mobility of 6.59 cm² V⁻¹ s⁻¹. The sprayed FTO film having minimum resistance of 3.42 Ω/cm², highest figure of merit of 6.18 × 10⁻² Ω⁻¹ at 550 nm and 96% IR reflectivity suggest, these films are useful as conducting layers in electrochromic and photovoltaic devices and also as the passive counter electrode.