活性层优化对有机小分子太阳能电池的影响

首先制备了给体(AlPcCl)和受体(C70)比例为1∶1的电池器件并采用不同的温度对电池进行退火处理,发现在120℃的温度下退火电池器件的性能最好,器件的转换效率从2.28;提高到2.47;,增加了8.3;.为进一步优化电池器件的性能,制备了在相同的活性层厚度下不同的给受体比例的电池器件,发现在给受体的厚度之比为1∶5时器件性能最好,电池开路电压为0.8V,短路电流为10.21 mA/cm2,填充因子为46.04;,转换效率为3.71;.     

n型IBC太阳电池选择性发射极工艺研究

为提升n型叉指背接触(IBC)太阳电池的光电转换效率,采用丝网印刷硼浆和高温扩散的方式形成选择性发射极结构,研究了硼扩散和硼浆印刷工艺对电池发射极钝化性能和接触性能的影响。实验结果表明,在硼扩散沉积时间和退火时间一定的条件下,硼扩散通源(BBr₃)流量为100 mL/min,沉积温度为830 ℃,退火温度为920 ℃时,发射极轻掺杂(p⁺)区域的隐开路电压达到710 mV,暗饱和电流密度为12.2 fA/cm²。发射极局部印刷硼浆湿重为220 mg时,经过高温硼扩散退火,重掺杂(p⁺⁺)区域的隐开路电压保持在683 mV左右,该区域方块电阻仅46 Ω/□,金属接触电阻为2.3 mΩ·cm². 采用该工艺方案制备的IBC电池最高光电转换效率达到24.40%,平均光电转换效率达到24.32%,相比现有IBC电池转换效率提升了0.28个百分点。     

平面硅异质结太阳电池的光吸收增强的研究

钙钛矿/硅叠层太阳电池可以充分利用太阳光谱,提高光电转换效率.平面硅异质结太阳电池可以作为叠层电池的底电池,其性能直接影响叠层电池的性能表现.采用传统反应热蒸发技术,在低温(170 ℃)条件下制备了掺锡氧化铟薄膜,并在170 ℃的氧气氛围下后退火处理,对ITO薄膜的特性进行了详细的表征和分析.结果表明:后退火工艺改善了ITO的结晶特性,使得材料的光学特性和电学特性得到明显提高,将其应用于平面硅异质结太阳电池,短路电流密度得到极大提高,尤其红外光响应改善明显.引入MgF2薄膜作为减反射层,进一步增强了电池的光响应,转换效率达到19.04;.     

阴极缓冲层PVP的插入对聚合物太阳能电池性能的影响

研究了聚乙烯吡络烷酮(PVP)作为阴极缓冲层对P3HT/PCBM基聚合物太阳能电池光电性能的影响.PVP分别溶于二甲基乙酰胺(DMAC)、N-甲基吡咯烷酮(NMP)、乙二醇乙醚、丙酮等不同溶剂中,研究了其旋涂过程及其对活性层薄膜的影响.结果表明:PVP作为P3HT∶ PCBM的阴极缓冲层,由于其产生的自集聚效应使活性层与阴极之间形成良好的欧姆接触,有利于电子的传输.当在活性层上面旋涂溶于N-甲基吡咯烷酮(NMP)的聚乙烯吡络烷酮(PVP)的溶液时,聚合物太阳能电池的开路电压Voc为0.57 V,短路电流为Jsc为10.9 mA/cm2,填充因子FF为62;,能量转换效率PCE为3.95;.与未加阴极缓冲层PVP的标准电池器件效率(2.62;)相比,效率提高了50;.     

新型阴极缓冲层对聚合物太阳能电池性能的影响

研究了引入有机小分子尿素(urea)作为阴极缓冲层的以P3HT∶ PCBM为活性层的体异质结聚合物太阳能电池(BHJ-PSCs).通过溶液旋涂法制备尿素层,并且以不同的旋涂速度得到不同厚度的尿素.在模拟的标准太阳光(100 mW/cm2)照射下,以3000 r/min的转速旋涂尿素得到的器件取得了9.15mA/cm2的短路电流密度,此时对应的能量转换效率较不加尿素层时的效率提高了20;,由2.8;增加到3.36;.原子力显微镜的测试表明,尿素层的引入改善了有机层和Al电极的接触.暗态J-V曲线的研究以及外量子效率的分析说明尿素层的引入抑制了载流子的复合,促进了载流子的传输与收集.尿素分子中氧原子上的孤对电子和Al发生强烈的化学反应,有效保护了活性层免受蒸镀的Al原子因注入带来的破坏,这种保护行为减少了载流子的复合,提高了器件的性能.     

CuSCN空穴传输层工艺对钙钛矿电池性能的影响

采用溶液法制备了硫氰酸亚铜(CuSCN)薄膜,并将其作为空穴传输层制备了平面n-i-p型钙钛矿太阳电池.系统考察了CuSCN薄膜退火温度、旋涂转速对钙钛矿太阳电池性能的影响.研究结果表明,CuSCN薄膜在70 ℃下退火10 min可以获得较好的电池性能;在此基础上通过调整旋涂转速至2000 r/min,控制CuSCN薄膜厚度约为240 nm,电池性能获得了进一步的提升,电池效率可达11.77;.该研究结果表明,CuSCN材料是一种有潜力的、低成本高性能无机空穴传输材料.     

电势诱导衰退和湿热衰退P-PERC太阳能电池的修复与增效

针对P型钝化发射极背面接触(PERC)太阳能电池在服役期间受到电势衰退和湿热诱导衰退影响而引起光电转换效率降低的问题,本文通过光电注入和热退火工艺对已衰退电池进行修复并研究其增效机制。实验结果表明:在光照强度为3倍标准太阳光、电注入电流为10 A、退火温度为150 ℃、工艺50 min实验条件下,对180片已衰退电池进行修复实验,其中94.32%的已衰退电池的光电转换效率得到修复,实验后电池光电转换效率平均提升8.96%。光致发光光谱和量子效率分析表明,光电注入和热退火工艺可有效减少电池因电势诱导衰退和湿热衰退形成的内部缺陷和背表面缺陷,提升衰退电池片的光电转换效率。     

硅异质结电池界面处理关键工艺的研究

薄膜硅/晶体硅异质结(HIT)太阳电池是界面器件,其界面性质直接决定器件的性能.本文采用简化的RCA清洗并结合氧化膜保护工艺对硅片进行前期处理;采用等离子体增强化学气相沉积技术(PECVD)制备薄膜硅/晶体硅异质结;通过光发射谱(OES)研究了PECVD在不同的匹配速度下起辉基元浓度随时间的变化,证实了基元浓度的不稳定对电池界面性质有一定的影响;分析了退火工艺对异质结的界面特性的影响,在10-4 Pa量级的背景真空和200℃下进行退火,可显著提高电池开路电压Voc和填充因子FF.本文结果表明:硅片前期处理的氧化膜保护工艺及后退火处理,皆可明显地改善HIT电池的界面性质、提高电池的转换效率.     

全TOPCon电池正面多晶硅层硼掺杂工艺

为提升隧穿氧化层钝化接触(TOPCon)电池光电转换效率,本文通过高温扩散在n型TOPCon电池正面制作p型隧穿氧化层钝化接触结构,提升发射极钝化性能,减少正面金属复合。本文研究了不同沉积时间、推进温度、推进时间等工艺参数对实验样品钝化性能及掺杂曲线的影响。实验结果表明,当沉积时间为1 500 s,推进温度为920℃,推进时间为20 min时,掺硼多晶硅层可获得较优的钝化性能及掺杂浓度,其中样品多晶硅层硼掺杂浓度达到1.40×10²⁰ cm^-3,隐开路电压(iV_oc)大于720.0 mV。依据该参数制备的TOPCon电池光电转换效率可达23.89%,对应的短路电流密度为39.36 mA/cm²,开路电压(V_oc)达到726.4 mV,填充因子(FF)为83.54%。     

绒面ZnO/Si异质结太阳能电池的初步研究

以p型单晶硅<100>作为衬底材料,通过化学腐蚀法得到硅绒面表面结构,采用喷雾热解法沉积掺Al的ZnO薄膜于绒面硅上,结合微电子光刻、磁控溅射和真空蒸镀等工艺制作上、下表面电极,于400 ℃氮气氛围下快速退火合金,得到Ag/Ti/n-ZnO/p-Si/Al异质结太阳能电池.对电池样品进行了原子力显微镜、霍尔效应测试、X射线衍射谱、电流电压特性等分析.得到电池最佳性能为:开路电压V_(oc)=355 mV,短路电流I_(sc)=36 mA,填充因子FF=0.41,电池效率达到5.2;.绒面异质结构有效降低了电池表面的光反射,相对增加了p-n结的有效面积,电池效率得到一定程度的提高.ZnO与Si界面之间SiO_2层的存在是目前影响电池效率的主要因素.     

Modelling of mechanism of agglomeration of KCl crystallization

The article presents an analysis into agglomeration during KCl vacuum crystallization. The theoretical and experimental investigations into the mechanism of agglomeration during mass crystallization result in an extension of the growth phenomena within the known model equations. The basis for this is essentially constituted by the collision model concepts of the theory of floculation in disperse systems. The parameters derived from the microprocess analysis (energy dissipation, content of solids, growth rate of individual grains) lead to model equations which are confirmed by laboratory and test trials.     

Relationship of Morphological Types of Dynamic Forms of Crystals

Crystallography Reports - The relationship of morphological spectra (sets of data on the morphological types of real polyhedral crystals and their probabilities under current physicochemical...     

Velocities of Disappearance and Lifetime of Faces of Growing Crystals

The formulae for absolute R_disap and relative R velocities of disappearance and lifetime τ of faces of growing crystals have been derived for stationary growth. It was shown that the quantities are determined by the relative growth velocity R_A/R_critA of the vanishing face A with respect to the critical growth velocity R_critA and by the geometry of a crystal expressed by the trigonometric functions of interfacial angles β and γ formed between face A and the adjacent faces. R increases and τ decreases with the increase in R_A/R_critA to certain limiting values. The calculations have been verified and illustrated by the experimental results for triclinic potassium bichromate (KBC) crystals. Results enable ones to predict values of velocities of disappearance and lifetimes of undesirable, supplementary faces of any real crystal.     

Development of Pauling's concepts of geometric characteristics of atoms

The evolution of the geometric characteristics introduced by Pauling and their dependence on the specific features of the structure and chemical bonds have been considered. The values of the covalent and van der Waals radii are given as well as their relationships and mutual transitions.     

A review of measurement of thermophysical properties of silicon melt

Measurements of thermophysical properties of Si melt and supplementary study of X-ray scattering/diffraction by the authors' group were reviewed. The values obtained differed variously from those of literature. Density was 2–3% larger, surface tension 20–30% smaller, viscosity up to 40% larger, electrical conductivity 8% smaller, spectral emissivity more or less in good agreement with literature values, and thermal diffusivity a few percent larger. An anomalous density jump was found near the melting point. Surface tension and viscosity also showed anomaly. A strange time-dependent change of density was observed over 3 h after melting. X-ray analyses suggested a slight change in local atom ordering, but showed no sign of cluster formation. An addition of 0.1 at% gallium caused the density jump to disappear, while that of boron caused no change. An EXAFS study of the former melt indicated a strong interaction between Ga and Si atoms as if molecules of GaSi₃ existed. The implications of the measured properties are a possibility of soft-turbulence in an Si melt in a relatively large crucible, a more complicated manner of intake of oxygen depleted molten Si from the free surface region to underneath the growing crystal, and a relaxation of the melt after melting arising from trapped gas species.     

Dependence of the parameters of equations of viscous flow on chemical composition of silicate melts

The temperature dependence of viscosity of silicate melts is discussed in the framework of the Avramov–Milchev (AM) equation. The composition is described by means of two parameters: the molar fraction, x, and the “lubricant fraction”, l. The molar fraction is the sum of the molar parts x_i of all oxides dissolved in SiO₂, the molar fraction of the latter being 1 ? x. It is shown that, with sufficient precision, two of the parameters of the AM equation can be presented as unique functions of the molar fraction. On the other hand, x is not sufficient to determine properly the reference temperature T_r , at which viscosity is η_r = 10¹³ [dPa.s]. Therefore, additional parameter, “lubricant fraction” l, is introduced. For each of the components, l_i is a product of molar part x_i and a specific dimensionless coefficient 0 ≤ k_i ≤ 1 accounting for the specific contribution of this component to the increased mobility of the system. It is demonstrated that, for l > 0, the reference temperature is related to the “lubricant fraction” l through the reference temperature T_r,SiO2 of pure SiO₂.     

Comparative analysis of two methods of calculation of the orientation of domain walls in ferroelastics

Two types of domain-wall equations are analyzed: the equations derived by the Sapriel method and the equations obtained by interface matching of the thermal-expansion tensor. It is shown that, for W-type domain walls, these methods yield the same equations. For W′-type domain walls, the equations obtained by different methods coincide for proper ferroelastics and differ for improper ferroelastics.     

Generation of crystal structures of heteromolecular compounds by the method of discrete modeling of packings

Within the method of discrete modeling of packings, an algorithm of generation of possible crystal structures of heteromolecular compounds containing two or three molecules in the primitive unit cell, one of which has an arbitrary shape and the other (two others) has a shape close to spherical, is proposed. On the basis of this algorithm, a software package for personal computers is developed. This package has been approved for a number of compounds, investigated previously by X-ray diffraction analysis. The results of generation of structures of five compounds—four organic salts (with one or two spherical anions) and one solvate—are represented.