首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
    
Thin‐film solar cells using Cu2ZnSn(S,Se)4 absorber materials continue to attract increasing attention. The synthesis of kesterite Cu2ZnSnS4 nanoparticles by a modified method of hot injection is explained. Characterization of the nanoparticles by energy dispersive X‐ray spectroscopy, X‐ray diffraction, Raman, and transmission electron microscopy is presented and discussed. When suspended in an ink, coated, and processed into a device, the nanoparticles obtained by this synthesis achieve a total area (active area) efficiency of 9.0% (9.8%) using AM 1.5 illumination and light soaking. This improvement over the previous efficiency of 7.2% is attributed to the modified synthesis approach, as well as fine‐tuned conditions for selenizing the coated nanoparticles into a dense absorber layer. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

2.
    
Optimization of the back contact interface is crucial for improving the performance of Cu2ZnSnS4 (CZTS) thin film solar cells. In this paper, self-depleted CuSCN is deployed as an intermediate layer at the Mo/CZTS interface to improve the quality of the back contact. This CuSCN layer, obtained via aqueous solution processing, reduces the thickness of Mo(S,Se)2 and eliminates multi-layer crystallization of the absorber by suppressing the undesirable reaction between Mo and Se during the selenization process. By regulating the selenium infiltration into the CZTS precursor films during the selenization process, highly crystalline, single-layer Cu2ZnSn(S,Se)4 (CZTSSe) absorber layers are realized. The single-layer CZTSSe absorber exhibits reduced carrier recombination, enhanced carrier density and increased work function. The improved back contact and absorber layer enables 11.1% power-conversion-efficiency to be achieved.  相似文献   

3.
    
Improving the efficiency of kesterite (Cu2ZnSn(S,Se)4; CZTSSe) solar cells requires understanding the effects of Na doping. This paper investigates these effects by applying a NaF layer at various positions within precursors. The NaF position is important because Na produces Na-related defects in the absorber and suppresses the formation of intrinsic defects. By investigating precursors with various NaF positions, the sulfo-selenization mechanism and the characteristics of defect formation are confirmed. Applying a NaF layer onto a Zn layer in a CZTSSe precursor limits Zn diffusion and suppresses Cu-Zn alloy formation, thus changing the sulfo-selenization mechanism. In addition, the surface NaF layer provides reactive Se and S to the absorber layer by generating Na2Sex and Na2Sx liquid phases during sulfo-selenization, thus limiting the incorporation of Na into the absorber and reducing the Na effects. Efficiency values of 11.16% and 11.19% are obtained for a flexible CZTSSe solar cell by applying NaF between the Zn layer and back contact and between the Cu and Sn layers, respectively. This study presents methods for doping with alkali metals and improving the efficiency of photovoltaics.  相似文献   

4.
    
The effects of doping at concentrations at the ppm level in organic photovoltaic cells were clarified using simple n+p-homojunctions. With doping from 0 to 10 ppm, the fill factor increased due to the appearance of majority carriers. From 10 to 100 ppm, the photocurrent density increased due to an increase in the built-in potential, i.e., the formation of an n+p-homojunction. The photocurrent was increased by a factor of 1.3 by directly doping the photoactive co-deposited layer with acceptor molecules at a concentration of 100 ppm.  相似文献   

5.
    
We recently introduced the buried emitter back‐junction solar cell, featuring large area fractions of overlap between n+‐type and p+‐type regions at the rear side of the device. In this paper we analyse the performance of the buried emitter solar cell (BESC) and its generalisations by one‐dimensional device simulations and analytical model calculations. A key finding is that the generalised versions of the BESC structure allows achieving very high efficiencies by passivating virtually the entire surface of p‐type emitters by an oxidised n‐type surface layer. A disadvantage of this type of full‐area emitter passivation in the generalised back‐junction BESC is the need for an insulating layer between the metallisation of the emitter and the contact to the base, which is technologically difficult to achieve. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

6.
We report on copper (Cu) electrodes fabricated with inkjet-printed nanoparticle inks that are photonic sintered on a polymer dielectric layer and their application to source and drain electrodes in organic thin-film transistor (TFT). By using photonic sintering with a radiant energy density of 9 J/cm2, printed Cu nanoparticle layers on a glass substrate showed very low electrical resistivity levels of 7 μΩ cm. By optimizing the sintering conditions on polymer dielectric, the pentacene-based TFT using these printed Cu electrodes showed good mobility levels of 0.13 cm2/Vs and high on/off current ratios of about 106. In addition, we revealed that the crystal grain growth of pentacene near the printed Cu electrodes was inhibited by the thermal damage of polymer underlayer due to the high radiant energy density of the intense light.  相似文献   

7.
    
A set of three commercial copper nanoparticle based inkjet inks has been benchmarked with respect to their potential to form conducting printed structures for future applications in organic electronic devices. Significant differences were observed in terms of jetting properties, spreading behaviour and line formation on a number of relevant substrates. The inks' stabilities against oxidation were investigated, inkjet printed patterns were subjected to photonic flash sintering and their electrical properties characterized. As a result, optimized conditions for printing and post-deposition processing were determined. Photonic flash sintering, which is a roll-to-roll compatible manufacturing process, allowed a significant reduction in sintering time. Flash sintering was performed in the presence of air, thereby excluding the necessity for processing under inert atmosphere. One product was identified which showed satisfactory performances regarding all tested features: stable jet formation, well-defined definition of the printed structures and high electrical conductivity (20% of the value of bulk Cu). The obtained results can be considered as a promising step towards the future application of Cu inks in organic electronic devices.  相似文献   

8.
    
It is widely considered that charge carrier extraction in bulk‐heterojunction organic photovoltaics (BHJ OPVs) is most efficient when the area of contact between the semiconductor layers and the electrodes is maximized and the electrodes are electrically homogeneous. Herein, it is shown that ≈99% of the electrode surface can in fact be insulating without degrading the efficiency of charge carrier extraction, provided the spacing of the conducting areas is less than or equal to twice the optimal thickness of the BHJ layer. This striking result is demonstrated for BHJ OPVs with both conventional and inverted device architectures using two different types of BHJ OPVs, namely, PCDTBT:PC70BM and the ternary blend PBDB‐T:ITIC‐m:PC70BM. This finding opens the door to the use of a large pallet of materials for optical spacers and charge transport layers, based on a low density of conducting particles embedded in a wide bandgap insulating matrix.  相似文献   

9.
    
Poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is one of the most successful conducting polymers in terms of commercialization. A method to readily obtain highly conductive and transparent PEDOT:PSS films is urgently needed. A simple method is introduced to enhance the conductivity of such films dramatically. By adding a series of mineral acids into the PEDOT:PSS aqueous solution directly, the conductivity is enhanced by 3–4 orders of magnitude. Mechanistic study reveals that the conductivity enhancement is dependent on boiling point, pKa value, softness parameter, and oxidability of the dopant acid. Specifically, acids with high boiling point, low pKa, and low softness parameter are able to induce phase separation between PEDOT and PSS, leading to secondary doping. If the dopant acid exhibits strong oxidability, the conductivity can also be enhanced via primary doping. H2SO4‐doped PEDOT:PSS films exhibit the highest conductivity of 2244 S cm−1. These films are employed as the transparent electrodes of poly(3‐hexylthiophene‐2,5‐diyl) (P3HT)‐based organic photovoltaic cells, and the power conversation efficiency reaches 3.13%. These results suggest direct acid doping of PEDOT:PSS solution is a facile approach to obtain highly flexible transparent electrodes.  相似文献   

10.
《Organic Electronics》2014,15(8):1836-1842
A copper oxide (CuO) nanoparticle ink was inkjet printed and photosintered in order to optimize electrical performance as a function of pattern dimension. For a given photosintering condition, electrical conductance varied strongly with line widths, ranging from 100 to 300 μm, illustrating the implications of printing and sintering complex circuit designs with varying feature sizes. By tuning the time delay between printing and sintering, exposure wavelength, radiant energy, pulse width and the distance between the light-source and substrate, photosintering conditions were optimized so that variations in sheet resistance for different line widths were minimized. Using optimized photosintering conditions, a sheet resistance value as low as 150 mΩ/□ (resistivity of 9 μΩ cm) and current carrying capacity of 280 mA for a 300 μm wide trace was achieved.  相似文献   

11.
    
Some mechanisms of charge transport in organic semiconductors and organic photovoltaic (OPV) cells can be distinguished by their predicted change in activation energy for the current, Ea, versus applied field, F. Ea versus F is measured first in pure films of commercially available regioregular poly(3‐hexylthiophene) (P3HT) and in the same P3HT treated to reduce its charged defect density. The former shows a Poole–Frenkel (PF)‐like decrease in Ea at low F, which then plateaus at higher F. The low defect material does not exhibit PF behavior and Ea remains approximately constant. Upon addition of [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM), however, both materials show a large increase in Ea and exhibit PF‐like behavior over the entire field range. These results are explained with a previously proposed model of transport that considers both the localized random disorder in the energy levels and the long‐range electrostatic fluctuations resulting from charged defects. Activation energy spectra in working OPV cells show that the current is injection‐limited over most of the voltage range but becomes transport‐limited, with a large peak in Ea, near the open circuit photovoltage. This causes a decrease in fill factor, which may be a general limitation in such solar cells.  相似文献   

12.
    
The three‐dimensional (3D) printed electronics additive manufacturing industry sector has grown substantially in the past few years, and there is increasing demand for different types of metallic nanoparticle inks in electronics printing for various applications. Metallic nanoparticle inks are commonly used for fabricating conductive tracks and patterns due to their relatively high electrical conductivity as compared to other types of inks, and they can be further categorized into single‐element metallic nanoparticle inks, alloy metallic nanoparticle inks, metallic oxide nanoparticle inks, and core–shell bimetallic nanoparticle (BNP) inks. It is critical to gain a deep understanding of the metallic nanoparticle inks used in 3D printed electronics as the material properties of these inks can directly affect the final electrical and mechanical properties of the printed patterns. This review presents an overview of the available metallic nanoparticle inks used for 3D printing of electronics, and critically reviews the strengths and weaknesses of each type of ink. Finally, the challenges of metallic nanoparticle inks in 3D printed electronics are also discussed along with the future outlook for 3D printed electronics.  相似文献   

13.
Electrically conductive silver nanoparticle ink patterns were fabricated using the inkjet printing method. Two different polymer films were used as the substrate materials. The patterns were exposed to humidity and salt fog and the electrical performance (sheet resistance and RF performance) as well as mechanical endurance (adhesion) were measured before and after the environmental tests. The electrical properties of the printed structures remained good in all the measurable samples. The adhesion between the ink and a substrate material appeared to be a greater challenge in harsh environments. Protection capabilities of one dip coated and one hot laminated barrier materials were evaluated during the environmental tests. The results showed that there is a need for environmental protection in printed electronics. Especially the laminated barrier films can offer a potential solution for shielding printed electronics in harsh environments as they can provide good mechanical protection, and can easily be integrated in roll-to-roll process.  相似文献   

14.
    
A novel simple laser digital patterning process to fabricate Ni‐based flexible transparent conducting panels using solution‐processed nonstoichiometric nickel oxide (NiOx) thin films and their applications for flexible transparent devices are reported in this study. A large‐scale synthesis route to produce NiOx nanoparticle (NP) ink is also demonstrated. A low‐power continuous‐wave laser irradiation photothermochemically reduces and sinters selected areas of a NiOx NP thin film to produce Ni electrode patterns. Owing to the innovative NiOx NP ink and substantially lowered applied laser power density, Ni conductors can be fabricated, for the first time to the best of the authors' knowledge, even on a polyethylene terephthalate substrate, which is known to have one of the lowest glass‐transition temperatures among polymers. The resultant Ni electrodes exhibit a high‐temperature oxidation resistance up to approximately 400 °C, and high corrosion resistance in tap water and even in seawater. Moreover, a superior mechanical stability of the Ni conductors is confirmed by tape‐pull, ultrasonic‐bath, bending/twisting, and cyclic bending (up to 10 000 cycles) tests. Finally, flexible transparent touch screen panels and electrical heaters are fabricated with mesh‐type Ni conductors to demonstrate possible applications.  相似文献   

15.
    
A method for fabricating high‐efficiency Cu2ZnSn(S,Se)4 (CZTSSe) solar cells is presented, and it is based on a non‐explosive, low‐cost, and simple solution process followed by a two‐step heat treatment. 2‐Methoxyethanol was used as a solvent, and Cu, Zn, Sn, chloride salts, and thiourea were used as solutes. A CZTSSe absorber was prepared by sulfurising and then selenising an as‐coated Cu2ZnSnS4 (CZTS) film. Sulfurisation in a sulfur vapour filled furnace for a long time (2 h) enhanced the crystallisation of the as‐coated CZTS film and improved the stability of the CZTS precursor, and selenisation promoted further grain growth to yield a void‐free CZTSSe film. Segregation of Cu and S at the grain boundaries, the absence of a fine‐grain bottom layer, and the large grain size of the CZTSSe absorber were the main factors that enhanced the grain‐to‐grain transport of carriers and consequently the short‐circuit current (Jsc ) and efficiency. The efficiency of the CZTS solar cell was 5.0%, which increased to 10.1% after selenisation. For the 10.1% CZTSSe solar cell, the external quantum efficiency was approximately 80%, the open‐circuit voltage was 450 mV, the short‐circuit current was 36.5 mA/cm2, and the fill factor was 61.9%. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

16.
    
The ferroelectric photovoltaic effect has promising potential for the next generation of solar cells. However, due to disadvantages such as wide bandgap and low fill factor (FF), the power conversion efficiency (PCE) values reported in ferroelectric photovoltaic devices remain considerably below expectations. Herein, enhanced photovoltaic effect in the films with the nanostructure of ferroelectric nanocrystalline particles embedded in the amorphous or poor crystalline matrix is investigated. The nanostructures are realized by controlled crystallization and doping in Zn0.92-xCux(Fe0.04Li0.04)O (ZCFLO) films. Benefiting from the improved carrier dynamic regulation in ferroelectric/boundary nanostructures and narrowed bandgap, the designed ZCFLO photoferroelectrics films exhibit high efficiency photovoltaic effect under AM 1.5G light, manifesting above-bandgap photovoltage, markedly improved FF (83.4%), switchable photoresponse (50.3 mA W−1), and high PCE (14.4%). Meanwhile, the simple method presented in this work is fully compatible with large-scale manufacturing processes and may find applications in cost-efficiency optoelectronic devices.  相似文献   

17.
    
Cu2ZnSnS4 (CZTS)/ZnS heterojunctions have been prepared by a successive deposition of ZnS and CZTS thin films by ultrasonic spray pyrolysis technique on glass substrates. The cupric chloride concentration has been varied in the starting solution in order to investigate its influence on device properties. CZTS/ZnS heterojunctions were characterized by recording their current-voltage characteristics at different temperatures. The obtained results exhibit a good rectifying behavior of the realized heterojunction. Analysis of these results yields saturation current, series resistance and ideality factor determination. From the activation energy of saturation current we inferred that the thermal emission through the barrier height is the dominant mechanism of the reverse current rather than the defects contribution.  相似文献   

18.
    
Doping is an effective strategy to tune the electrical properties of organic semiconductors. Traditional solution-processed doping methods, including “host-dopant mixing-doping” and “post-fabrication doping” methods, present challenges for their use in applications in optoelectronic devices. This work reports about a novel method to prepare electrically doped films, the authors call orthogonal liquid-liquid-contact (OLLC) doping. In OLLC doping, dopant and polymer semiconductors are dissolved in water and an organic solvent, respectively, and electrical doping occurs during film formation at the orthogonal liquid-liquid (aqueous-organic) interface. A large free volume of polymer and dopant in their solutions enables diffusion for effective doping. Thanks to the high surface tension of water, nanometer-thick polymer films form spontaneously on the aqueous surface and simultaneously get doped. The doped thin polymer films on the aqueous surface can be easily transferred to devices to facilitate hole collection/injection in organic photovoltaics and light-emitting diodes with solution-processed top electrodes.  相似文献   

19.
         下载免费PDF全文
Cu2MgSnS4(CZTS)is a promising photovoltaic absorber material,however,efficiency is largely hindered by potential fluctuation and a band tailing problem due to the abundance of defect complexes and low formation energy of an intrinsic CuZndefect.Alternatives to CZTS by group I,II,or IV element replacement to circumvent this challenge has grown research in-terest.In this work,using a hybrid(HSE06)functional,we demonstrated the qualitative similarity of defect thermodynamics and electronic properties in Cu2MgSnS4(CMTS)to CZTS.We show SnMgto be abundant when in Sn-and Cu-rich condition,which can be detrimental,while defect properties are largely similar to CZTS in Sn-and Cu-poor.Under Sn-and Cu-poor chemic-al potential,there is a general increase in formation energy in most defects except SnMg,CuMgremains as the main contribu-tion to p-type carriers,and SnMgmay be detrimental because of a deep defect level in the mid gap and the possibility of form-ing defect complex SnMg+MgSn.Vacancy diffusion is studied using generalized gradient approximation,and we find similar va-cancy diffusion properties for Cu vacancy and lower diffusion barrier for Mg vacancy,which may reduce possible Cu-Mg dis-order in CMTS.These findings further confirm the feasibility of CMTS as an alternative absorber material to CZTS and suggest the possibility for tuning defect properties of CZTS,which is crucial for high photovoltaic performance.  相似文献   

20.
江丰  沈鸿烈 《半导体光电》2011,32(6):756-761,796
Cu2ZnSnS4（CZTS）薄膜材料成本低廉且无毒,其电学性能主要由自身所含的缺陷决定,一般呈P型导电性。CZTS的禁带宽度为1．5eV左右,在可见光范围内的光学吸收系数一般都大于10^4cm^-1,所以其非常适合作为太阳电池的吸收层。经过国内外学者10余年的努力,CZTS太阳电池光电转换效率提升明显。相信不久的将来,CZTS薄膜电池必将得到广泛的应用。主要介绍了CZTS材料的制备方法、CZTS材料性能和CZTS太阳电池的研究进展。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号