绒面ZnO:Al(ZAO)透明导电薄膜的制备

利用中频交流磁控溅射方法，采用氧化锌铝(98wt％ZnO 2wt％A12O3)陶瓷靶材制备了绒面ZAO(ZnO：Al)薄膜，考察了所制备的绒面ZAO薄膜与绒面SnO2：F薄膜在绒度、粗糙度、表面形貌以及电学性质的差异，利用原子力显徽镜对薄膜表面形貌进行了分析并计算出薄膜表面粗糙度，利用紫外可见分光光度计和电阻测试仪测量了薄膜的光学、电学特性。结果表明：所制备的绒面ZAO薄膜具有与绒面SnO2：F薄膜相比拟的各种性能，在非晶硅太阳电池中具有潜在的应用前景。     

非晶／微晶硅叠层电池中间层的研究进展

由于非晶硅光致衰退、微晶硅吸收系数低的原因,叠层结构电池成为提高电池效率和稳定性的有效途径.叠层电池各子电池较薄、太阳光的利用率较低,因此陷光结构在叠层电池中的作用尤其重要.具有绒面结构的前电极、叠层电池的中间层以及ZnO/Al或ZnO/Ag复合背电极共同组成硅薄膜太阳电池的陷光结构.中间层位于各子电池之间,作用是改变界面反射率,影响电池中光的传播路径.该文综述了叠层电池中间层的作用、要求以及此方面国内外的研究现状,并指出中间层研究中需要注意的主要问题和未来发展的趋势.     

太阳选择性吸收涂层系列讲座(14) 活性环境空心阴极溅射特性与沉积Al_2O_3、ZnO掺杂和In_2O_3:Mo薄膜的应用(下)

<正>2.4 ZnO掺杂透明导电氧化物沉积透明导电氧化物薄膜,例如SnO2、ITO、ZnO,有很多应用,如建筑玻璃、汽车、显示器、光伏器件。制备掺杂氧化锌膜用射频或脉冲直流溅射陶瓷靶,它含有ZnO和2%(重量比)Al2O3,无论如何靶的代价是过高的,而能用的功率密度是有限的。最近反应磁控溅射Zn:Al靶受到关注,虽然它需电压控制和氧分压强的闭环控制以保证工作在金属/氧化物过渡模式。     

非晶硅太阳能电池生产中沉积SnO2膜的均匀性

介绍了用化学气相法沉积大面积SnO2透明电膜的原理和方法。通过沉积器具有工艺的改进,提高了大面积SnO2膜方块电阻和光透过率的均匀性。讨论了SnO2膜均匀性对非晶硅太阳电池的影响。     

研制高效硅太阳电池的新进展

本文报道了我们研制的2×2cm~2、n~ /p硅太阳电池。它采用了绒面、硼背场、铝背反射器、Ti-Pd-Ag电极以及TiO_x-Al_2O_3双层减反射膜。在25℃、AM0条件下的最优样品电池输出功率达80.6mW。 实验表明:(1)硼背场导致电池开路电压增加50-60mV;(2)用1—2％的NaOH水溶液可腐蚀出接近于理想的绒面。这种表面结构与硼背场和TiO_x-Al_2O_3双层减反射膜相结合,使电池短路电流显著提高,与常规电池相比,约增加7.5mA/cm~2。     

光面晶体硅-陷光膜复合电池光电特性研究

晶体硅表面制绒虽然会降低太阳光的反射损失,但也会造成其表面损伤,从而制约晶体硅电池转换效率的提高。对这一问题设计光面晶体硅-陷光膜复合电池结构,经理论分析和实验表明:陷光膜可有效减少光的反射损失,光面晶体硅的光生伏特效应比绒面强,复合电池转换效率比绒面晶体硅电池提高2.2%。     

ZnO与TiO2的质量比对染料敏化太阳能电池性能的影响

采用低温水溶液法制备ZnO微米棒;ZnO微米棒与TiO2纳米粉以不同比例混合,制备复合浆料;采用刮涂法把复合浆料涂敷在透明导电玻璃上,制备ZnO/TiO2复合薄膜光阳极。通过电池的I-U特性和电化学阻抗谱测试,研究ZnO微米棒与TiO2纳米粉的比例对电池性能的影响。结果表明:当ZnO与TiO2的质量比为1∶1时,DSSC的效率最高,此时的光电转换效率比纯TiO2电池的效率提高了31%。这主要得益于ZnO微米棒更高的光利用率和良好的电子转移特性。     

硅基薄膜太阳电池(十四)

2绒面透明导电膜绒面透明导电膜是实现光管理不可或缺的重要材料,是薄膜电池研究中的重点课题,尤其在对有源层材料的研究近乎日臻完善的状况下,光利用就成为提高效率的重要手段。不仅如此,对过去很少关注的掺杂层和透明导电层自身的光吸收问题也已经提上日程,说明效率的提高已经到了需要精益求精的程度。这与单晶硅电池研究后期正     

高效率硅太阳电池的性能及理论分析

1981年8月,我们研制成功绒面BSFR(背表面场和背反射器结合)高效率硅太阳电池,其最高效率达15.3％(AM0,300K)。 本文报道了电池的研制情况及测试结果,讨论了背表面场、背反射器以及绒面结构等对电池性能的影响,着重分析了掺杂对进一步提高电池效率的影响。     

ZnO薄膜对CIGS太阳电池性能的影响

采用交流磁控溅射制备高阻ZnO和直流溅射ZnO：A1薄膜,研究几种溅射工艺条件与ZnO薄膜性能关系以及对铜铟镓硒(CIGS)光伏电池的影响。通过不同的工艺参数改变控制,得到了性能优良的ZnO薄膜,同时表明电池窗口层ZnO薄膜工艺参数对铜铟硒电池性能影响至关重要。尤其是ZnO薄膜的电阻率和迁移率,这两项指标的优化可以使电池的填充因子有10％以上的提高。不论是高阻ZnO还是低阻ZnO薄膜对电池的填充因子都有着重要的影响,采用优化工艺所制备的C1GS光伏电池窗口层ZnO薄膜以后,目前研制的电池转换效率已达到12．1％。     

Structural and optical properties of textured ZnO:Al films on glass substrates prepared by in-line rf magnetron sputtering

Textured ZnO:Al films with excellent light scattering properties as a front electrode of silicon thin film solar cells were prepared on glass substrates by an in-line rf magnetron sputtering, followed by a wet-etching process to modify the surface morphologies of the films. Deposition parameters and wet etching conditions of the films were controlled precisely to obtain the optimized surface features. All as-deposited films show a strong preferred orientation in the [0 0 1] direction under our experimental conditions. The microstructure of the films was significantly affected by working pressure and film compactness was reduced with increasing working pressure, while the effect of a substrate temperature on the microstructure is less pronounced. A low resistivity of 4.25×10⁻⁴ Ω cm and high optical transmittance of above 80% in a visible range were obtained in the films deposited at 1.5 mTorr and 100 °C. After wet etching process, the surface morphologies of the films were changed dramatically depending on the microstructure and film compactness of the initial films. By controlling the surface feature, the haze factor and angular resolved distribution of the textured ZnO:Al films were improved remarkably when compared with commercial SnO₂:F films. The textured ZnO:Al and SnO₂:F films were applied as substrates for a silicon thin film solar cells with tandem structure of a-Si:H/μc-Si:H. Compared with the solar cells with the SnO₂:F films, a significant enhancement in the short-circuit current density of the μc-Si:H bottom cell was achieved, which is due to the improved light scattering on the highly textured ZnO:Al film surfaces in the long wavelength above 600 nm.     

ZnO:Al绒面透明导电薄膜的制备及分析

利用中频脉冲磁控溅射方法,采用Al掺杂(质量百分比2%)的Zn(纯度99.99%)金属材料为靶材制备平面透明导电ZnO:Al(ZAO)薄膜。利用湿法腐蚀方法,将平面ZAO薄膜在0.5%的稀盐酸中浸泡一定时间后,形成表面凹凸起伏的绒面结构。研究了平面ZAO薄膜的结构特性以及衬底温度、溅射功率和腐蚀时间对绒面ZAO薄膜表面形貌的影响,并对腐蚀前后薄膜的电阻变化进行了分析。结果表明:高温、低功率条件下制备的绒面ZAO薄膜表面形貌较好,在硅薄膜太阳电池中具有潜在的应用前景。     

High quality textured ZnO:Al surfaces obtained by a two-step wet-chemical etching method for applications in thin film silicon solar cells

ZnO:Al films deposited at 250 °C on Corning glass by radio frequency magnetron sputtering were studied for their use as front contact for thin film silicon solar cells. For this purpose, a two-step etching method combining different concentrations of diluted hydrochloric acid (from 0.1% to 3%) with different etching times was developed. Its influence on morphological, electrical and optical properties of the etched films was evaluated. This new etching method led to more uniform textured surfaces, where the electrical properties remained unchangeable after the etching process, and with adapted light scattering properties similar to those exhibited by commercial substrates.     

Preparation of ZnO thin films using MOCVD technique with D2O/H2O gas mixture for use as TCO in silicon-based thin film solar cells

Zinc oxide (ZnO) thin films have been successfully grown by metal organic chemical vapor deposition (MOCVD) technique using deuterium water (D₂O) and water (H₂O) mixtures as oxidants for diethylzinc (DEZ). B₂H₆ was also employed as a dopant gas. It was found that the crystal orientation of ZnO films strongly depends on D₂O/H₂O ratio. As a result, the surface morphology of ZnO changed from textured surface morphology to smooth surface morphology with increase in the ratio of D₂O/H₂O. Moreover, it was also observed that the carrier concentration of ZnO films did not change with the ratio of D₂O/H₂O, while the mobility of these films was strongly dependent on the D₂O/H₂O ratio. Without D₂O addition, the resistivity of films had its lowest value and the minimum sheet resistance was 10 Ω/square. All films showed transmittance higher than 80% in the visible region. Moreover, the haze values of these films could be controlled by the ratio of D₂O/H₂O. These results indicate that the crystal orientation and surface morphology of the low resistivity ZnO films can be modified by using a mixture of D₂O and H₂O without changing the deposition temperature. Thus, the obtained ZnO films are promising for use as a front TCO layer in Si-based thin film solar cells.     

TiO2/ZnO/TiO2 sandwich multi‐layer films as a hole‐blocking layer for efficient perovskite solar cells

A continuous and compact hole‐blocking layer is crucial to prevent photocurrent recombination at the photoanode/electrode interface of high‐performance mesostructure perovskite‐based solar cells. Novel TiO₂/ZnO/TiO₂ sandwich multi‐layer compact film prepared as hole‐blocking layer for perovskite solar cell. Herein, TiO₂, ZnO, and TiO₂ layers were successfully deposited by spin‐coating onto FTO glass substrate in sequence. The fill factor and power conversion efficiency of the perovskite solar cell are remarkably improved by the employment of a TiO₂/ZnO/TiO₂ sandwich compact layer. Perovskite solar cell based on TiO₂/ZnO/TiO₂ sandwich film has been observed to exhibit maximum incident‐photon‐to‐current conversion efficiency in the visible region (400–780 nm) and reach a power conversion efficiency of 12.8% under AM1.5G illumination. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of ITO precursor thickness on transparent conductive Al doped ZnO film for solar cell applications

Al doped ZnO (AZO) film was continuously deposited on ITO precursor on glass substrate by d.c. magnetron sputtering. The thickness of ITO was varied from 30 to 120 nm in order to investigate the effect of ITO thickness on crystallinity of AZO film. X-ray diffraction measurement shows that AZO film grown on ITO has an enhanced (0 0 2) preferred orientation as the ITO thickness was increased. The crystalline structure improvement of AZO film with an increase of ITO precursor thickness is due to the near-epitaxial growth of AZO on ITO precursor. As the ITO thickness was increased, mobility of AZO film by the Hall measurement was significantly increased from 5.4 cm²/V s (no ITO) to 23.6 cm²/V s (ITO 120 nm), and resistivity was about 81.7% improved from 1.99×10⁻³ to 3.63×10⁻⁴ Ω cm. The AZO films with ITO revealed excellent average transmission of visible (90.0%) and NIR (89.6%) regions, whereas those of AZO film without ITO were 82.1% and 88.1%, respectively. The haze values of AZO film with ITO of 90 and 120 nm are similar or higher than those of AZO film without ITO. The surface textured AZO film with ITO precursor is promising for optoelectronic applications such as the front TCO of thin film solar cells.     

TCO and light trapping in silicon thin film solar cells

For thin film silicon solar cells and modules incorporating amorphous (a-Si:H) or microcrystalline (μc-Si:H) silicon as absorber materials, light trapping, i.e. increasing the path length of incoming light, plays a decisive role for device performance. This paper discusses ways to realize efficient light trapping schemes by using textured transparent conductive oxides (TCOs) as light scattering, highly conductive and transparent front contact in silicon p–i–n (superstrate) solar cells. Focus is on the concept of applying aluminum-doped zinc oxide (ZnO:Al) films, which are prepared by magnetron sputtering and subsequently textured by a wet-chemical etching step. The influence of electrical, optical and light scattering properties of the ZnO:Al front contact and the role of the back reflector are studied in experimentally prepared a-Si:H and μc-Si:H solar cells. Furthermore, a model is presented which allows to analyze optical losses in the individual layers of a solar cell structure. The model is applied to develop a roadmap for achieving a stable cell efficiency up to 15% in an amorphous/microcrystalline tandem cell. To realize this, necessary prerequisites are the incorporation of an efficient intermediate reflector between a-Si:H top and μc-Si:H bottom cell, the use of a front TCO with very low absorbance and ideal light scattering properties and a low-loss highly reflective back contact. Finally, the mid-frequency reactive sputtering technique is presented as a promising and potentially cost-effective way to up-scale the ZnO front contact preparation to industrial size substrate areas.     

Nano-structured Cu2O solar cells fabricated on sparse ZnO nanorods

Nano-structured Cu₂O/ZnO nanorod (NR) heterojunction solar cells fabricated on indium tin oxide (ITO)-coated glass are studied. Substrate film and NR density have a strong influence on the preferred growth of the Cu₂O film. The X-ray diffractometer (XRD) analysis results show that highly (2 0 0)-preferred Cu₂O film was formed when plating on plain ITO substrate. However, a highly (1 1 1)-preferred Cu₂O film was obtained when plating on sparse ZnO NRs. SEM, TEM and XRD studies on sparse NR samples indicate that the Cu₂O nano-crystallites mostly initiate its nucleation on the peripheral surfaces of the ZnO NRs, and are also highly (1 1 1)-oriented. Solar cells with ZnO NRs yielded much higher efficiency than those without. In addition, ZnO NRs plated on a ZnO-coated ITO glass significantly improve the shunt resistance and open-circuit voltage (V_oc) of the devices, with consistently much higher efficiency obtained than when ZnO NRs are directly plated on ITO film. However, longer NRs do not improve the efficiency due to low short-circuit current (J_sc) and slightly higher series resistance. The best conversion efficiency of 0.56% was obtained from a Cu₂O/ZnO NRs heterojunction solar cell fabricated on a 80 nm ZnO-coated ITO glass with V_oc=0.514 V, J_sc=2.64 mA/cm² and 41.5% fill factor.     

Study on diffusion barrier layer of silicon-based thin-film solar cells on polyimide substrate

ZnO and Ni films were used as the diffusion barrier layer between Al and n-type μc-Si:H for the hydrogenated amorphous silicon (a-Si:H) solar cells on polyimide (PI) substrate. The electrical, optical and uniformity properties of ZnO or Ni film influence strongly the performance and uniformity of solar cells. The uniformity of the solar cells with ZnO diffusion barrier layer degraded with the increasing thickness of ZnO film. The uniformity of solar cells with Ni diffusion barrier layer was more than 90%, which was generally better than those with ZnO film. A power-to-weight ratio of 200 W/kg was obtained for a-Si:H thin-film solar cell on PI substrate with a size of 14.8 cm².     

PEN as substrate for new solar cell technologies

The possible use of polyethylene naphthalate as substrate for low-temperature deposited solar cells has been studied in this paper. The transparency of this polymer makes it a candidate to be used in both substrate and superstrate configurations. ZnO:Al has been deposited at room temperature on top of PEN. The resulting structure PEN/ZnO:Al presented good optical and electrical properties. PEN has been successfully textured (nanometer and micrometer random roughness) using hot-embossing lithography. Reflector structures have been built depositing Ag and ZnO:Al on top of the stamped polymer. The deposition of these layers did not affect the final roughness of the whole. The reflector structure has been morphologically and optically analysed to verify its suitability to be used in solar cells.