Detection of finger interruptions in silicon solar cells using photoluminescence imaging

Finger interruptions are common problems in screen printed solar cells, resulting in poor performance in efficiency because of high effective series resistance. Electroluminescence（EL） imaging is typically used to identify interrupted fingers. In this paper, we demonstrate an alternative method based on photoluminescence（PL） imaging to identify local series resistance defects, with a particular focus on finger interruptions. Ability to detect finger interruptions by using PL imaging under current extraction is analyzed and verified. The influences of external bias control and illumination intensity on PL images are then studied in detail. Finally, in comparison with EL imaging, the using of PL imaging to identify finger interruptions possesses the prominent advantages： in PL images, regions affected by interrupted fingers show higher luminescence intensity, while regions affected by recombination defects show lower luminescence intensity. This inverse signal contrast allows PL imaging to more accurately identify the defect types.

H^+ Passivation of Poly-Si Solar CellsProcessed by Different Annealing Processes

The effects of different annealing processes on the photovoltaic (PV) properties and the spectral response as well as minority carrier lifetime in the bulk of unanalyzed PF5 ion implantation poly-Si solar cells were investigated. The different hydrogen passivation effects of defects in poly-Si induced by three heat treatment processes are reported. We used RTA-rapid thermal annealing, YAG pulse laser annealing and CTSA-classical three-step annealing for this study. The results show that cells processed by RTA (800°C, 4 sec) achieved the best PV properties and spectral response among all annealed samples. Under this precess condition, no or few defects were induced in bulk. While RTA (>-850°C for 4 sec), CTSA as well as YAG laser processes induced defects of different nature and concentration in the bulk of cells. It is further shown that hydrogen ion implantation significantly improved, the performances of poly-Si cells. It is able to efficiently remove the YAG laser induced defects in bulk. However, it cannot completely passivate the defects induced by CTSA and RTA processes.

Solar Energy Cell with Rare Earth Film

The characteristic of the solar energy cell with the rare earth film according to theory of molecular structure was introduced.When sunlight shines, the molecules of the rare earth film can absorb energy of the photon and jump to the excited state from the basic state, and play a role in storing solar energy.When sunlight do not shine, the electron of the excited state returns to the basic state, the rare earth film can automatically give out light and shine to surface of the solar cell, which can make solar cell continuously generate electric current.The rare earth film can absorb direct,scattering sunlight, and increase density of solar energy to reach surface of the solar cell, and play focusing function.The rare earth film can bear 350 ~ 500 ℃, which make the solar cell be able to utilize the focusing function system.Because after luminescence of the rare earth film, it can release again the absorbed solar energy through 1 ~ 8 h, and play a role in storing solar energy; The solar cell with the rare-earth film can generate electricity during night and cloudy days, and remarkably increase efficiency of the solar cell.

New design of ferroelectric solar cell combined with luminescent solar concentrator

A new transparent photovoltaic panel composed of a luminescent solar concentrator and Al/BaTiO3/ZnO/Pt ferroelectric solar cells is presented,in which a portion of the incoming solar illumination is converted by the fluorophores to ultraviolet(UV)light which is then absorbed by ZnO.Firstly,the solar cells are simulated using Atlas-Silvaco.Then,the panel is modelled based on the obtained solar cell characteristics.This panel would be of great importance for building integrated photovoltaics domain because of its high transparency.

上转换发光纳米材料对钙钛矿太阳能电池迟滞效应和离子迁移动力学的影响

迟滞效应是影响钙钛矿太阳能电池性能和稳定性的重要问题,离子迁移和由此产生的界面离子积累是引起迟滞效应最重要的原因之一。本研究采用上转换发光纳米材料(Upconversion Luminescent Nanoparticles,UCNP)修饰电子传输层/钙钛矿活性层的界面及本征钙钛矿活性层,系统探究了UCNP对钙钛矿的形貌、结构、光谱/光电性能和离子迁移动力学的影响。结果表明:钙钛矿活性层经过UCNP修饰后器件的光电转换效率(Power Conversion Efficiency,PCE)最佳(16.27%),而且迟滞因子(Hysteresis Factor,HF)得到显著改善(0.05)。进一步采用回路切换瞬态光电技术系统探究了钙钛矿太阳能电池不受光生载流子干扰的离子迁移动力学过程,证明UCNP在光电转换过程中起到抑制离子累积和迁移的双重作用:一方面UCNP可以形成阻隔层,阻碍离子累积;另一方面,UCNP可以在退火过程中进入到钙钛矿体相晶界处,阻碍离子迁移,使恢复电压从0.43 V降低到0.28 V。极化诱导缺陷态模型解释了离子-载流子相互作用机制,阐释了UCNP抑制钙钛矿光伏器件迟滞效应的机理。本研究可以为调控钙钛矿太阳能电池迟滞提供一种有效的解决方案。

近红外SrGa_(12)O_(19)荧光粉特性及能量传递

采用高温固相法制备了一种共掺Cr^(3+)和Yb^(3+)的SrGa_(12)O_(19)荧光粉.通过X射线衍射仪、扫描电子显微镜和光致发光光谱对荧光粉的物相纯度、化学组成和发光性能进行表征.结果显示:当以Cr^(3+)的4A_(2)→4T_(1)激发位置(468 nm)激发Cr^(3+)和Yb^(3+)共掺杂的SrGa_(12)O_(19)荧光粉时,SrGa_(12)O_(19)荧光粉的发射光谱中同时出现了Cr^(3+)和Yb^(3+)的发射峰,这表明在SrGa_(12)O_(19)基质中存在Cr^(3+)→Yb^(3+)的能量传递.样品中Yb^(3+)的发射范围在950~1100 nm,与晶体硅(c-Si)太阳能电池的光谱响应区域相匹配.提高Cr^(3+)的掺杂浓度,不仅能够增强Yb^(3+)的发光强度,而且样品在207℃下的光强度为初始发光强度的82.1%.研究结果可为SrGa_(12)O_(19)荧光粉在c-Si太阳能电池光谱转换提高效率提供借鉴与参考.

Concentration effect of the near-infrared quantum cutting of 1788-nm luminescence of Tm^(3+) ion in(Y_(1-x)Tm_x)_3Al_5O_(12) powder phosphor

In the present paper, the concentration effect of near-infrared quantum cutting of Tm3＋ ion in （Y1-xTmx）3Al5Ol2 powder phosphor is studied by means of experiments and calculations. In addition, the absorption spectra, visible-to-near- infrared excitation and emission spectra, and fluorescence lifetimes are measured. It is found that （Y1-xTmx）3Al5O12 powder phosphor has a strong four-photon near-infrared quantum cutting luminescence of 1788.0-nm 3F4 →3H6 fluores- cence of Tm3＋ ion, when excited by 357.0-nm light. It is also found that the up-limit of the four-photon near-infrared quantum cutting luminescence efficiency of （Yo.700Tmo.300）3Al5 O12 powder phosphor is approximately 302.19%. To the knowledge of the authors, this is the first time that a near-infrared quantum cutting efficiency up-limit exceeding 300% has been reported. The results of this manuscript are valuable in aiding the probing of the new generation Ge solar cell.

稀土掺杂铅卤钙钛矿发光、光电材料与器件研究进展

铅卤化物钙钛矿作为一类新兴的光电子材料表现出了卓越的光学、电学性能,在太阳能电池、发光二极管、光电探测器以及激光等领域产生了广泛而重要的应用,引起万众瞩目。稀土是元素周期表里一类特殊材料,从57号到71号元素,具有4f^(n)和4f^(n-1)5d电子组态。如果将稀土和钙钛矿材料以及器件相结合,会孕育出怎样的新生儿呢?本文旨在结合作者在相关领域开展的工作及取得的经验,简单梳理该领域近年来取得的进展,剖析未来所面临的问题和挑战。本文不以总结纷繁复杂的个性化现象为要扼,而以探讨具有普遍意义的共性问题为宗旨。在资料选取上,或许失之偏颇,有严重的“王婆卖瓜”之嫌,请读者慎思明辨。

Microscopic Study of Defect Luminescence between 0.72 - 0.85 eV by Optical Microscopy

In this contribution, an experimental setup to investigate the defect luminescence between 0.72 - 0.85 eV of single defects in Silicon by optical microscopy is introduced. For this purpose, an optical microscope is equipped with an InGaAs CCD detector and a longpass filter with a cut-off wavelength at 1450 nm in order to filter out the band-to-band luminescence at around 1.1 eV. Grain boundaries showing homogeneous distributed defect luminescence can be localized at a μm-scale.

Pt/Y2O3：Eu3＋ composite nanotubes： Enhanced photoluminescence and application in dye-sensitized solar cells

Y（OH）3：Eu3＋ nanotubes were synthesized using a facile hydrothermal method, and then, Pt particles were grown on the surface of the nanotubes using a combination of vacuum extraction and annealing. The resulting Pt/Y2O3：Eu3＋ composite nanotubes not only exhibited enhanced red luminescence under 255- or 468-nm excitation but could also be used to improve the efficiency of dye- sensitized solar cells, resulting in an efficiency of 8.33%, which represents a significant enhancement of 11.96% compared with a solar cell without the com- posite nanotubes. Electrochemical impedance spectroscopy results indicated that the interfacial resistance of the TiO2-dyel I3/I- electrolyte interface of the TiO2-Pt/Y203：Eu3~ composite cell was much smaller than that of a pure TiO2 cell. In addition, the TiO2-Pt/Y2O3：Eu3＋ composite cell exhibited a shorter electron transport time and longer electron recombination time than the pure TiO2 cell.

Application of upconversion luminescence in dye-sensitized solar cells

An upconversion luminescence powder TiO2:(Er3+,Yb3+) is prepared by a hydrothermal method and used to fabricate dye-sensitized solar cell (DSSC).The TiO2:(Er3+,Yb3+) powder undergoes upconversion luminescence,converting infrared light which the dye can not absorb into visible light with wavelengths of 510-700 nm which the dye can absorb,increasing the photocurrent of the DSSC.TiO2:(Er3+,Yb3+) also acts as a p-type dopant,heightening the Fermi level of the oxide film,which increases the photovoltage of the DSSC.The best performance of the DSSC is found when the ratio of TiO2/luminescence powder is 1/3 in the luminescence layer.Under simulated solar irradiation of 100 mW cm-2 (AM 1.5),the DSSC containing TiO2:(Er3+,Yb3+) doping achieves a light-to-electricity energy conversion efficiency of 7.28% compared with 6.41% for the undoped DSSC.

羧基调控含炔基铼染料发光性能的理论研究

染料分子的光物理性质与染料敏化太阳能电池(Dye-sensitized solar cell,DSSC)的性能密切相关。为了研究炔基氮杂环铼三羰基配合物中羧基吸附基团对染料发光性能的影响,采用密度泛函理论(density functional theory,DFT)方法对孤立染料分子及其吸附在TiO_(2)(101)表面后的结构、前线分子轨道和光谱性质进行了计算,预测了其在染料敏化太阳能电池中的光电转换效率。计算结果表明,羧基吸附基团的位置和数目不同时,虽然染料分子的结构相似,但可以调控发光性质。羧基连接在含N杂环上比在其他位置时,染料分子表现出来较好的发光性能。另外,通过对比所有染料分子的吸收可见光范围、驱动力和光捕获效率,最终筛选出发光性质优良的染料分子a^(4)和b4,其具有好的光吸收能力和强的电荷传输能力,适合作为染料敏化剂。

硅半导体太阳能电池进展

太阳能电池是将太阳能直接转化为电能的装置,也是有效利用太阳能最佳途径之一。作为一种绿色能源,尤其是在核电安全问题面临挑战的今天,太阳能电池被认为是解决能源衰竭和环境污染等一系列重大问题的最佳选择。目前,许多国家正在制订中长期太阳能开发计划,准备在21世纪大规模开发太阳能。当前研究最多同时在生产应用的最广泛的当数硅太阳能电池(如单晶硅、多晶硅、非晶硅等)。通过对各类硅太阳能电池的性能、工艺、转化效率以及制备方法等方面作比较并讨论了它们各自性能的优劣,最后结合当前国内外工业化生产状况,对硅太阳能电池研究现状和各自的最新进展作了比较详细的综述,并简要讨论了硅太阳能电池研究和生产上的前景及趋势。

Ho^(3+)上转换发光在染料敏化太阳能电池中的应用

以水热和高温煅烧相结合的方法制备了掺Ho3+的TiO2上转换发光层,并将其组装在染料敏化太阳能电池中。通过XRD、荧光光谱仪、UV-vis和电池的光电性能测试,来分析上转换发光层的发光机理及其加入后对染料敏化太阳能电池性能的影响。结果表明,上转换发光层的引入有效地提高了DSSC的光电性能,在80mW/cm2红外光照射下最高光电转换效率达到了0.12‰,比未加上转换发光层的DSSC提高了360%。

Gd_2O_3∶Er^(3+)上转换发光粉在染料敏化太阳电池中的应用

采用沉淀-煅烧法制备了Gd2O3∶Er3+上转换发光粉,通过X射线衍射、扫描电子显微镜、能谱和荧光光谱对其进行了表征,并利用该发光粉具有上转换发光的特性将其应用于染料敏化太阳电池(DSSC)。结果表明,管状Gd2O3∶Er3+上转换发光粉可增加电池对太阳光的吸收范围和吸收效率,提高电池的光电流和光电压。研究了掺杂量对电池性能的影响,当掺杂量为5wt%时,光电转换效率从5.93%升高到7.55%,提高约27%。

上转换发光在染料敏化太阳能电池中的应用

以水热和高温煅烧相结合的方法制备了掺Er3+的TiO2上转换发光层,并将其组装在染料敏化太阳能电池(DSSC)中。通过XRD﹑荧光光谱﹑UV-Vis和电池的光电性能测试,分析了上转换发光层的发光机理及其加入后对染料敏化太阳能电池性能的影响。结果表明,上转换发光层的引入有效地提高了DSSC的光电性能,在80mW·cm-2红外光照射下最高光电转换效率达到了0.14‰,比未加上转换发光层的DSSC提高了160%。

太阳能电池及多晶硅的生产

在简述太阳能电池原理和发展的基础上,分析了太阳能电池用多晶硅的生产方法.认为:改良的熔盐电解法和熔盐三层电解精炼法有可能直接制取太阳能级多晶硅,此法一旦研究成功,将大幅度地降低太阳能级多晶硅生产成本,应引起人们的关注.

用开路电压法测硅太阳电池中少数载流子寿命

太阳电池基区的少数载流子寿命是影响电池效率的重要因素之一。开路电压衰减法 (OCVD)具有直接、简单、重复性好等特点 ,可准确测量器件的少数载流子寿命。该文分别介绍了利用纳秒激光器和发光二极管 (LED)作为OCVD的光源 ,测量晶体硅太阳电池的少子寿命 ,结果发现可以利用脉冲信号发生器带动发光二极管作为脉冲光源 ,取代纳秒激光器 。

a-Si:H薄膜的再结晶技术及Si膜的Raman光谱分析

论述了非晶硅薄膜的几种主要再结晶技术 ,着重指出了各种晶化技术已取得的研究成果、优缺点、有待进一步研究的内容及其在多晶硅薄膜太阳电池工业生产中的应用前景。另外 ,还讨论了通过Raman光谱求纳晶硅薄膜的晶粒尺寸和结晶度的方法。

下转换发光粉Y_2O_3/Sm^(3+)在染料敏化太阳能电池中的应用

采用沉淀法制备了Y2O3/Sm3+下转换发光粉,利用X射线衍射、荧光光谱对其进行了表征,并利用该发光粉具有下转换发光的特点将其应用于染料敏化太阳能电池(DSSC).结果表明,Y2O3/Sm3+下转换发光粉可以增加电池对太阳光的吸收范围,提高电池的光电流和光电压.研究了掺杂量对电池性能的影响,当掺杂量为3%时,光电转换效率从5.049%提高到5.94%,表明了其是一种有效提高光电转换效率的方法.