新型硒化锑薄膜太阳电池背接触优化

硒化锑(Sb₂Se₃)具有低毒、原材料丰富和光电性能优异等优点,被认为是最具有发展潜力的薄膜太阳电池光吸收层材料之一.但目前Sb₂Se₃薄膜太阳电池光电转换效率与碲化镉、铜铟镓硒和钙钛矿等太阳电池相比仍存在较大差距.限制Sb₂Se₃薄膜太阳电池光电转换效率进一步提升的关键因素之一是,太阳电池结构中Mo背电极和Sb₂Se₃薄膜构建的背接触界面处容易形成较高的势垒,降低载流子的抽取效率.本工作则对Mo背电极进行热处理生成缓冲层MoO₂薄膜,发现缓冲层MoO₂的引入,可有效地促进Sb₂Se₃薄膜的择优取向生长,同时实现太阳电池Mo/MoO2/Sb₂Se₃背接触势垒降低,相应的填充因子、开路电压和短路电流密度均获得显著提高,构建的太阳电池光电转换效率从5.04%提升至7.05%.     

Sb2Se3薄膜表面和界面超快载流子动力学的瞬态反射光谱分析

Sb₂Se₃是一种低成本、环境友好、具有良好应用前景的光伏材料.目前Sb₂Se₃太阳能电池的光电转换效率已经提高到了10%.载流子复合动力学是决定Sb₂Se₃太阳能电池光电转换效率的关键因素.本文利用飞秒时间分辨表面瞬态反射谱详细分析了Sb₂Se₃表面、Sb₂Se₃/CdS界面载流子复合动力学过程.根据相对反射率变化?R/R的演化,得到Sb₂Se₃载流子热化、带隙收缩时间约为0.2—0.5 ps,估计热载流子冷却时间为3—4 ps.还实验证实在Sb₂Se₃/CdS界面处存在自由电子转移和浅束缚电子转移两种电子转移过程.本文提供了Sb₂Se₃表面瞬态反射谱分析方法,所得实验结果拓展了对Sb₂Se₃表...     

基于形变势理论的掺杂计算Sb2Se3空穴迁移率

硒化锑(Sb₂Se₃)是一种元素丰富、经济且无毒的太阳电池吸收层材料.太阳电池的性能在很大程度上取决于载流子的传输特性,然而在Sb₂Se₃中,这些特性尚未得到很好的理解.通过密度泛函理论和形变势理论,本文对纯Sb₂Se₃以及掺杂了As, Bi的Sb₂Se₃的空穴传输特性进行研究,计算并分析了影响迁移率的3个关键参数:有效质量、形变势和弹性常数.结果显示,有效质量对迁移率具有最大影响,掺杂Bi的Sb₂Se₃表现出最高的平均迁移率.同时发现, Sb₂Se₃的空穴迁移率呈现出明显的各向异性,其中x方向的迁移率远高于y,z方向,这应该与x方向的原子主要以较强的共价键连接,而y, z方向以较弱的范德瓦耳斯力连接有关.载流子传输能力强的方向有助于有效传输和收集光生载流子,本研究从理论上强调了控制Sb₂Se_3...     

基于Si掺杂Sb2Te3薄膜的相变存储器研究

采用磁控三靶(Si，Sb及Te)共溅射法制备了Si掺杂Sb₂Te₃薄膜，作为对比，制备了Ge₂Sb₂Te₅和Sb₂Te₃薄膜，并且采用微加工工艺制备了单元尺寸为10μm×10μm的存储器件原型来研究器件性能.研究表明，Si掺杂提高了Sb₂Te₃薄膜的晶化温度以及薄膜的晶态和非晶态电阻率，使得其非晶态与晶态电阻率之比达到10⁶，提高了器件的电阻开/关比；同Ge₂Sb₂Te₅薄膜相比，16at% Si掺杂Sb₂Te₃薄膜具有较低的熔点和更高的晶态电阻率，这有利于降低器件的RESET电流.研究还表明，采用16at% Si掺杂Sb₂Te₃薄膜作为存储介质的存储器器件原型具有记忆开关特性，可以在脉高3V、脉宽500ns的电脉冲下实现SET操作，在脉高4V、脉宽20ns的电脉冲下实现RESET操作，并能实现反复写/擦，而采用Ge₂Sb₂Te₅薄膜的相同结构的器件不能实现RESET操作. 关键词： 相变存储器 硫系化合物 2Te₃薄膜')" href="#">Si掺杂Sb₂Te₃薄膜 SET/RESET转变     

Bi-Sb-Te基热电薄膜温差电池离子束溅射制备与表征

本文采用离子束溅射Bi/Te和Sb/Te二元复合靶,直接制备n型Bi₂Te₃热电薄膜和p型Sb₂Te₃热电薄膜.在退火时间同为1 h的条件下,对所制备的Bi₂Te₃薄膜和Sb₂Te₃薄膜进行不同温度的退火处理,并对其热电性能进行表征.结果表明,在退火温度为150 ℃时,制备的n型Bi₂Te₃关键词： 薄膜温差电池 2Te₃薄膜')" href="#">Sb₂Te₃薄膜 2Te₃薄膜')" href="#">Bi₂Te₃薄膜 离子束溅射     

Bi4Se3薄膜的声子结构及电声子相互作用的第一性原理研究

基于密度泛函微扰理论,运用第一性原理研究两种终结面的Bi₄Se₃薄膜的声子结构和电-声子相互作用.结果表明两种终结面的Bi₄Se₃薄膜体系都是动力学稳定的. Bi₄Se₃薄膜中插入的Bi₂双原子层与Bi₂Se₃五原子层的声子投影态密度并不完全匹配,这会阻碍部分声子的输运,降低热导,从而有利于提高材料的热电性能.另外,两种终结面的Bi₄Se₃薄膜的电-声子耦合系数都不太大（约0.278）,有利于制备基于室温工作的电子学器件.     

甲脒碘化铅单晶基钙钛矿太阳能电池的研究

近年来,CH(NH₂)₂PbI₃(FAPbI₃)由于其带隙接近理想值而受到了广泛关注,成为钙钛矿太阳能电池中最具吸引力的光电功能材料.然而由碘甲脒(FAI)和碘化铅(PbI₂)作为前驱体制备的传统钙钛矿层化学计量比不精准,缺陷密度大,稳定性差且结晶度较低,导致钙钛矿太阳能电池性能很难进一步提高.本文采用FAPbI₃单晶制备的钙钛矿薄膜具有高结晶度,高稳定性,精确的化学计量比和低缺陷密度.单晶钙钛矿薄膜的晶粒尺寸大,晶界少,导致晶界处缺陷较少,提高了钙钛矿太阳能电池的短路电流密度(J_SC)和开路电压(V_OC),使其光电转换效率有了大幅度的提高.本文为制备高稳定性、高结晶度和低缺陷密度的钙钛矿太阳能电池提供了一种有效策略.     

Cu对用于高速相变存储器的Sb2Te薄膜的结构及相变的影响研究

采用原位X射线衍射仪、拉曼光谱仪和X射线反射仪分别研究了Cu-Sb₂Te 薄膜的微结构、成键结构和结晶前后的密度变化. Sb₂Te薄膜的结晶温度随着Cu含量的增加而增大. 在10 at.%和14 at.% Cu的Sb₂Te薄膜中, Cu与 Te 成键, 结晶相由六方相的Cu₇Te₄、菱形相的Sb及六方相的Sb₂Te构成. 10 at.% 和14 at.% Cu 的Sb₂Te薄膜在结晶前后的厚度变化分别约为3.2%和 4.0%, 均小于传统的Ge₂Sb₂Te₅ (GST)薄膜. 制备了基于Cu-Sb₂Te薄膜的相变存储单元, 并测试了其器件性能. Cu-Sb₂Te器件均能在10 ns的电脉冲下实现可逆SET-RESET操作. SET和RESET操作电压随着Cu含量的增加而减小. 疲劳测试结果显示, Cu 含量为10 at.%和14 at.%的PCRAM单元的循环操作次数分别达到1.3×10⁴和1.5×10⁵, RESET和SET态的电阻比值约为100. Cu-Sb₂Te可以作为应用于高速相变存储器(PCRAM)的候选材料.     

Femtosecond Fiber Laser Based on BiSbTeSe2 Quaternary Material Saturable Absorber

Topological insulator materials, including Bi₂Te₃, Sb₂Te₃, Sb₂Te₃, and Bi₂Se₃, have attracted some attention due to their narrow band gaps, high carrier mobility, wide spectral absorption ranges and other characteristics.We report a new multi-compound topological insulator material BiSbTeSe₂ that, compared with the traditional topological insulator composed of two elements, can integrate the physic...     

锰酸锂掺杂Fe和Co的性质的第一性原理计算

文章基于密度泛函理论的第一性原理计算,研究了LiMn₂O₄电池材料在掺杂Fe和Co离子时的电子结构和电化学性能.发现Fe\Co取代Mn³⁺在热力学上是会更加稳定,提升电化学性能.掺杂Fe后,LiMn₂O₄电池材料晶格参数减小(约0.3%);掺杂Co后,LiMn₂O₄电池材料晶格参数减小(约0.5%).这两种掺杂方式让与之相邻的Mn³⁺被氧化成Mn⁴⁺,从而降低了Jahn-Teller畸变情况产生可能性.对于掺Fe尖晶石型锰酸锂(Li₈Mn₁₅FeO₃₂),Mn环境中的Li离子会更容易被提取,第一次放电电压从原来的3.7 V增加至4.623 V;对于掺Co尖晶石型锰酸锂(Li₈Mn₁₅CoO₃₂),第一次放电电压从原来的3.7 V增加至4.101 V.研究为锂电池...     

硒化锑薄膜太阳电池的模拟与结构优化研究

采用wx-AMPS模拟软件对硒化锑(Sb_2Se_3)薄膜太阳电池进行建模仿真,将CdS, ZnO和Sn02的模型应用到Sb_2Se_3太阳电池的电子传输层中.结果显示,应用CdS和ZnO都能实现较高的器件性能,并发现电子传输层电子亲和势(Xe-ETL)的变化能够调节Sb_2Se_3太阳电池内部的电场分布,是影响器件性能的关键参数之一.过高或者过低的Xe-ETL都会使电池的填充因子降低,导致电池性能劣化.当Xe-ETL为4.2eV时,厚度为0.6μm的Sb_2Se_3太阳电池取得了最优的7.87%的转换效率.应用优化好的器件模型,在不考虑Sb_2Se_3层缺陷态的理想情况下,厚度为3μm的Sb_2Se_3太阳电池的转换效率可以达到16.55%(短路电流密度J_(SC)=34.88 mA/cm~2、开路电压V_(OC)=0.59 V、填充因子FF=80.40%).以上模拟结果表明,Sb_2Se_3薄膜太阳电池在简单的器件结构下就能够获得优异的光电性能,具有较高的应用潜力.     

An n—n type heterojunction enabling highly efficientcarrier separation in inorganic solar cells

Carrier separation in a solar cell usually relies on the p—n junction. Here we show that an n—n type inorganic semiconductor heterojunction is also able to separate the exciton for efficient solar cell applications. The n—n type heterojunction was formed by hydrothermal deposition of Sb₂(S,Se)₃ and thermal evaporation of Sb₂Se₃. We found that the n—n junction is able to enhance the carrier separation by the formation of an electric field, reduce the interfacial recombination and generate optimized band alignment. The device based on this n—n junction shows 2.89% net efficiency improvement to 7.75% when compared with the device consisted of semiconductor absorber—metal contact. The study in the n—n type solar cell is expected to bring about more versatile materials utility, new interfacial engineering strategy and fundamental findings in the photovoltaic energy conversion process.     

Inverted organic solar cells with solvothermal synthesized vanadium-doped TiO_2 thin films as efficient electron transport layer

We investigated the effects of using different thicknesses of pure and vanadium-doped thin films of TiO_2 as the electron transport layer in the inverted configuration of organic photovoltaic cells based on poly(3-hexylthiophene) P3HT:[6-6] phenyl-(6) butyric acid methyl ester(PCBM). 1% vanadium-doped TiO_2nanoparticles were synthesized via the solvothermal method. Crystalline structure, morphology, and optical properties of pure and vanadium-doped TiO_2 thin films were studied by different techniques such as x-ray diffraction, scanning electron microscopy, transmittance electron microscopy, and UV–visible transmission spectrum. The doctor blade method which is compatible with roll-2-roll printing was used for deposition of pure and vanadium-doped TiO_2 thin films with thicknesses of 30 nm and 60 nm. The final results revealed that the best thickness of TiO_2 thin films for our fabricated cells was 30 nm. The cell with vanadium-doped TiO_2 thin film showed slightly higher power conversion efficiency and great J_(sc) of 10.7 mA/cm~2 compared with its pure counterpart. In the cells using 60 nm pure and vanadium-doped TiO_2 layers, the cell using the doped layer showed much higher efficiency. It is remarkable that the external quantum efficiency of vanadium-doped TiO_2 thin film was better in all wavelengths.     

十二烷二酸修饰TiO_2电子传输层改善钙钛矿太阳电池的电流特性

在经典的平面异质结钙钛矿太阳电池中,TiO_2致密层的电子传输性能一直是获得优异光伏性能的决定性因素之一.相较于spriro-OMe TAD等常见的空穴传输材料优异的空穴传输能力,作为电子传输材料的TiO_2的导电性较弱,无法形成良好的电荷匹配.为了解决这个问题,我们使用自组装的十二烷二酸(DDDA)单分子层来修饰TiO_2致密层的表面,TiO_2致密层的导电性能得到大幅提升,并且其能带结构得到优化,促进了电子传输,降低了电子积聚和载流子复合,使得电池的短路电流密度(JSC)从修饰前的20.34 mA·cm~(-2)提升至修饰后的23.28 mA·cm~(-2),进而使得电池在标准测量条件下的光电能量转换效率从14.17%提升至15.92%.同时还发现,通过DDDA修饰TiO_2致密层,所制备的器件的光稳定性显著提升,器件未封装暴露在AM 1.5光强100 mW·cm~(-2)的模拟太阳光下超过720 min,保持初始效率的71%以上且趋于稳定.     

First-principles calculations of nitrogen-doped antimony triselenide: A prospective material for solar cells and infrared optoelectronic devices

This study is focused on calculation of the electronic structure and optical properties of non-metal doped Sb2Se3 using the first-principles method. One and two N atoms are introduced to Sb and Se sites in a Sb₂Se₃ crystal. When one and two N atoms are introduced into the Sb₂Se₃ lattice at Sb sites, the electronic structure shows that the doping significantly modifies the bandgap of Sb₂Se₃ from 1.11 eV to 0.787 and 0.685 eV, respectively. When N atoms are introduced to Se sites, the material shows a metallic behavior. The static dielectric constants ε1(0) for Sb₁₆Se₂₄, Sb₁₅N₁Se₂₄, Sb₁₄N₂Se₂₄, Sb₁₆Se₂₃N₁, and Sb₁₆Se₂₂N₂ are 14.84, 15.54, 15.02, 18.9, and 39.29, respectively. The calculated values of the refractive index n(0) for Sb₁₆Se₂₄, Sb₁₅N₁Se₂₄, Sb₁₄N₂Se₂₄, Sb₁₆Se₂₃N₁, and Sb₁₆Se₂₂N₂ are 3.83, 3.92, 3.86, 4.33, and 6.21, respectively. The optical absorbance and optical conductivity curves of the crystal for N-doping at Sb sites show a significant redshift towards the short-wave infrared spectral region as compared to N-doping at Se sites. The modulation of the static refractive index and static dielectric constant is mainly dependent on the doping level. The optical properties and bandgap narrowing effect suggest that the N-doped Sb₂Se₃is a promising new semiconductor and can be a replacement for GaSb due to its very similar bandgap and low cost.     

Inverted polymer solar cells with employing of electrochemical-anodizing synthesized TiO_2 nanotubes

An inverted structure of polymer solar cells based on Poly(3-hexylthiophene)(P3HT):[6-6] Phenyl-(6) butyric acid methyl ester(PCBM) with using thin films of TiO_2 nanotubes and nanoparticles as an efficient cathode buffer layer is developed. A total of three cells employing TiO_2 thin films with different thickness values are fabricated. Two cells use layers of TiO_2 nanotubes prepared via self-organized electrochemical-anodizing leading to thickness values of 203 and 423.7 nm, while the other cell uses only a simple sol–gel synthesized TiO_2 thin film of nanoparticles with a thickness of 100 nm as electron transport layer. Experimental results demonstrate that TiO_2 nanotubes with these thickness values are inefficient as the power conversion efficiency of the cell using 100-nm TiO_2 thin film is 1.55%, which is more than the best power conversion efficiency of other cells. This can be a result of the weakness of the electrochemical anodizing method to grow nanotubes with lower thickness values. In fact as the TiO_2 nanotubes grow in length the series resistance(Rs) between the active polymer layer and electron transport layer increases, meanwhile the fill factor of cells falls dramatically which finally downgrades the power conversion efficiency of the cells as the fill factor falls.     

高效无空穴传输层碳基钙钛矿太阳能电池的制备与性能研究

碳基钙钛矿太阳能电池因稳定性高、成本低廉而备受关注,但由于钙钛矿与碳电极之间能级匹配度不高,界面阻力大而导致效率不及金属基钙钛矿太阳能电池.本文制备了碳基无空穴传输层FTO/c-TiO₂/m-TiO₂/CH₃NH₃PbI₃/Carbon电池结构.通过对介孔二氧化钛层、钙钛矿层厚度进行优化,并对钙钛矿的薄膜形貌及钙钛矿激发电子寿命、可见光吸收度、载流子的提取与分离等进行深度分析,讨论了电池效率提升的内在机理.当介孔氧化钛层和钙钛矿层达到最优厚度时,钙钛矿太阳能电池获得了开路电压（V_oc）为0.93 V、电流密度（J_sc）为21.75 mA/cm²、填充因子为55%、光电转化效率达到11.11%.同时对电池进行了稳定性研究,在室温湿度为40%–50%的条件下放置15 d电池性能依旧稳定保持原来的95%,优于金属基钙钛矿太阳能电池,从而为碳电极钙钛矿太阳能电池的商业化发展提供了可能.     

胆甾液晶掺杂活性层对有机太阳能电池性能的影响

以poly(3-hexylthiophene)(P3HT)为电子给体,indene-C60bisadduct(ICBA)为电子受体,通过掺杂不同浓度胆甾液晶氯化胆甾醇制备了有机体异质结太阳能电池.结果表明,适当浓度掺杂使器件的开路电压提高到了0.78 V,但短路电流密度却有所降低,填充因子几乎不变,能量转换效率提高了10%.利用X射线、光致发光、原子力显微镜及紫外-可见吸收光谱进行表征,发现液晶掺杂对活性层的结晶度、分子内部排列情况、薄膜表面形貌和光吸收特性等都有明显影响.     

基于Al_2O_3/MoO_3复合阳极缓冲层的倒置聚合物太阳能电池的研究

采用旋涂Al_2O_3前驱体溶液和低温退火的方法在活性层上形成Al_2O_3薄膜,并与MoO_3结合形成Al_2O_3/MoO_3复合阳极缓冲层,制备了以聚3-己基噻吩:[6.6]-苯基-C_(61)-丁酸甲酯(P3HT:PC_(61)BM)为活性层的倒置聚合物太阳能电池,并通过改变Al_2O_3前驱体溶液的浓度来分析复合阳极缓冲层对器件性能的影响.结果发现,Al_2O_3/MoO_3复合阳极缓冲层能有效调控倒置聚合物太阳能电池的光电性能及其稳定性.当Al_2O_3前驱体溶液的浓度为0.15%时,器件光伏性能达到最优值,与MoO_3单缓冲层的器件相比,光电转换效率(PCE)由3.85%提高到4.64%;经过80天老化测试后,具有复合阳极缓冲层的器件PCE保留为初始值的76%,而单缓冲层的器件PCE已经下降到50%以下.器件性能得到改善的原因是Al_2O_3/MoO_3复合阳极缓冲层增强了倒置太阳能电池器件阳极对空穴的收集能力,同时钝化了器件活性层,从而提升了太阳能电池器件的光伏性能及其稳定性.     

Growth mechanism and characterisation of chemically grown Sb doped Bi2Se3 thin films

The synthesis of combinatorial Bi_2−xSb_xSe₃ thin films by arrested precipitation technique (APT) using triethanolamine-bismuth, triethanolamine-antimony and sodium selenosulphite as sources of Bi³⁺, Sb³⁺ and Se²⁻, respectively is investigated on commercial glass substrates. The growth mechanism of film formation, composition and surface morphology of the as deposited films were studied as a function of preparative parameters and bath composition. The films were monophasic, polycrystalline and covered the surface of the substrate completely. Energy dispersive X-ray analysis gave coherent elemental composition indicating single phase BiSbSe₃ was made. The good results obtained for Bi_2−xSb_xSe₃ thin films revealed that arrested precipitation technique is best suited for the deposition of large area thin films on conducting/nonconducting substrates to produce materials for device applications.