晶硅衬底参数对背接触太阳电池性能的影响

利用Silvaco-TCAD半导体器件仿真软件对n型插指背接触(IBC)晶硅太阳电池衬底参数进行了优化,全面系统地分析了晶硅衬底厚度、电阻率、少子寿命对IBC太阳电池量子效率、短路电流、开路电压、转换效率的影响.结果表明:晶硅衬底少子寿命是影响IBC太阳电池性能的最主要因素.少子寿命越高,电池转换效率越高.当晶硅衬底电阻率为2Ω·cm,少子寿命为500 μs时,最优的衬底厚度范围为60～65μm,IBC太阳电池转换效率约为22.5％.利用高质量晶硅材料制备IBC太阳电池时,可降低对衬底厚度的要求.当晶硅衬底厚度为150 μm、少子寿命为500μs时,最优衬底电阻率为0.3 Ω·cm,IBC太阳电池转换效率约为23.3％.少子寿命越低,IBC太阳电池最优的衬底电阻率越大.     

聚光背结背接触太阳电池衬底电阻率和光强的优化研究

利用TCAD半导体器件仿真软件对中低倍聚光光伏系统中应用的N型插指背接触(Interdigitated Back Contact,IBC)单晶硅太阳电池的电学性能进行了仿真研究,全面系统地分析了不同衬底电阻率和光强对电池短路电流密度、开路电压、填充因子及转换效率的影响。结果表明:IBC太阳电池的电学性能受到衬底电阻率和光强的显著影响。当光强较小(0.1 W/cm~2)时,随着衬底电阻率的增大,IBC太阳电池转换效率随之降低,最优的衬底电阻率为0.5?·cm。当光强较高(0.5~5 W/cm~2)时,随着衬底电阻率的增大,IBC太阳电池转换效率随之增大,最优的衬底电阻率为3?·cm。当光强进一步增大(10~50 W/cm~2)时,随着衬底电阻率的增大,IBC太阳电池转换效率呈现出先增大后减小的变化特点,最优的衬底电阻率为2?·cm。     

背接触太阳电池的背面设计优化

利用quokka3仿真软件建立三维模型,对n型叉指背接触(IBC)单晶硅太阳电池的单元电池结构设计和栅线参数进行了仿真优化,并通过激光和丝网印刷进行了实验验证。实验结果表明,在不同IBC单元电池结构设计下,当p+发射区与n+背表面场区的宽度比值为4时,IBC太阳电池效率比宽度比值为2.3时的高0.11%。可通过减小单元电池宽度,增大p+发射区与n+背表面场区的宽度比值来获得更高的IBC太阳电池效率。在相同单元电池结构设计下,当细栅线宽度从40μm增加到60μm时,IBC太阳电池效率能够提高0.18%。且相比4主栅,6主栅IBC太阳电池效率可提高0.09%。因此,增加副栅线宽度和主栅线数量有利于IBC太阳电池效率的提升。     

浅结密栅线硅太阳电池工艺研究

通过提高发射区方块电阻,配合密栅线丝网印刷工艺,制备了性能优良的多晶硅太阳电池。对比两种不同扩散工艺的方块电阻和ECV浓度,分析发射区方块电阻对太阳电池电性能参数的影响。结果表明:方阻为80Ω/□的发射区比70Ω/□的发射区的太阳电池串联电阻增加了0.03mΩ,导致填充因子下降0.05%,但是开路电压和短路电流密度分别提高了0.9mV和0.13mA/cm2,最终转换效率仍然提高了0.08%。     

工业级纳米绒面多晶硅太阳电池的发射极扩散方阻调控其光电转换性能研究

本文制备了工业级纳米绒面多晶硅太阳电池,研究 了发射极扩散方阻对其光电转换 性能的影响。结果表明:提高发射极扩散方阻能够有效地提升电池的开路电压、短路电流, 但填充因子相对降低。通过分析关键光电参数,其原因归结为:提高发射极扩散方阻有利于 降低发射极及其表面载流子复合,但过高的发射极扩散方阻将导致发射极与金属栅线接触不 良。采用优化的发射极扩散方阻,纳米绒面相对于微米绒面多晶硅太阳电池具有改善的光电 转换性能,产线均值光电转换效率达到了19.20%。基于上述研究结果 ,讨论了进一步通过调控发射极扩散方阻来优化纳米绒面多晶硅太阳电池的方法。     

N 型背接触晶硅太阳电池前表面场研究

利用 Silvaco 公司的 Athena 工艺仿真软件和 Atlas 器件仿真软件,对 N 型插指背结背接触(InterdigitatedBack Contact,IBC)晶硅太阳电池普遍采用的前表面场（FSF）结构进行研究,详细分析了 IBC 晶硅电池 FSF 表面掺杂浓度及扩散深度对电池性能的影响。结果表明：具有不同表面掺杂浓度和扩散深度的 FSF 对 IBC 晶硅太阳电池短路电流密度(Jsc)、开路电压(Voc)和填充因子(FF)产生显著影响,从而影响电池的转换效率(Eff)。具有较低表面浓度、深扩散 FSF 结构的 IBC 晶硅太阳电池可获得较高转换效率,当表面掺杂浓度为 5×1017cm–3时,电池转换效率Eff最高,且随 FSF 扩散深度增加略有增加,最高转换效率可达 22.3%。     

铁掺杂对不同导电类型硅材料电阻率的影响

采用电阻率为4.8Ω·cm的p型硅片和10Ω·cm的n型硅片,通过高温扩散法制备出了Fe掺杂的补偿硅材料.在室温避光条件下,测量样品电阻率p,并用XRD对扩散后的样品进行分析,研究了Fe掺杂对不同导电类型硅材料电阻率的影响.结果表明:相对于n型硅材料,深能级杂质Fe掺杂对p型硅材料电阻率的影响更大,其Fe掺杂p型硅材料电阻率远大于Fe掺杂n型硅材料;当p型硅表面Fe扩散源浓度为1.74× 10-5 mol/cm2时,在1 200℃下扩散1h后,材料具有最大电阻率7 246Ω· cm.     

硅太阳电池扩散方阻与栅线宽度匹配的研究

研究了扩散方块电阻及印刷栅线宽度变化对太阳电池电性能的影响,根据初步实验结果提出假设,通过进一步实验进行验证。结果表明：适当地提高扩散方阻、降低栅线宽度,有利于短路电流及效率的提升。但受限于串联电阻的增大,方阻及线宽存在一个最优值,通过Matlab软件建立模型进行模拟,求出最优解。证明了扩散方阻需要与栅线宽度很好地匹配才能达到理想的效果。     

高效率MINP硅太阳电池的研制

用扩散法制作MINP硅太阳电池的轻掺杂N区,用PECVD方法淀积的Si_3N_4作其减反射膜,在电阻率为1.5±0.5Ω·cm的P型硅衬底上制取了转换效率为16.5%的MINP太阳电池(有效面积AM1.5、100mw/cm~2、25℃)。本文分析Si_3N_4作MINP电池减反射膜的优点,并对限制MINP太阳电池性能进一步提高的因素进行讨论。     

高方阻密栅电池发射结方阻的优化

主要介绍了晶体硅太阳电池光电转换效率的工艺优化,特别是对高发射结方阻方面,以及后道工序中如何使之适应高方阻工艺。在高方阻方面主要采用了深结高方阻,这主要是从工艺稳定性方面考虑。通过一系列工艺的优化及大量实验,获得了高达635 mV的开路电压,5.817 A的短路电流,均值18.67%的电池效率。     

Gapless point back surface field for the counter doping of large‐area interdigitated back contact solar cells using a blanket shadow mask implantation process

Gapless interdigitated back contact (IBC) solar cells were fabricated with phosphorous back surface field on a boron emitter, using an ion implantation process. Boron emitter (boron ion implantation) is counter doped by the phosphorus back surface field (BSF) (phosphorus ion implantation) without gap. The gapless process step between the emitter and BSF was compared to existing IBC solar cell with gaps between emitters and BSFs obtained using diffusion processes. We optimized the doping process in the phosphorous BSF and boron emitter region, and the implied V_oc and contact resistance relationship of the phosphorous and boron implantation dose in the counter doped region was analyzed. We confirmed the shunt resistance of the gapless IBC solar cells and the possibility of shunt behavior in gapless IBC solar cells. The highly doped counter doped BSF led to a controlled junction breakdown at high reverse bias voltages of around 7.5 V. After the doping region was optimized with the counter doped BSF and emitter, a large‐area (5 inch pseudo square) gapless IBC solar cell with a power conversion efficiency of 22.9% was made.     

高效率n型硅离子注入双面太阳电池

为进一步提升n型硅双面太阳电池的转化效率,采用了磷离子注入技术制备n型硅双面太阳电池的背场.基于离子注入技术准直性和均匀性好的特点,掺杂后硅片的表面复合电流密度降低到了1.4×10-13 A/cm2,隐性开路电压可达670 mV,且分布区间更紧凑.在电阻率为1～3 Ω·cm的n型硅片基底上,采用磷离子注入技术工业化生产的n型硅双面太阳电池的正面平均转化效率达到了20.64％,背面平均转化效率达到了19.52％.内量子效率的分析结果显示,离子注入太阳电池效率的增益主要来自长波段光谱响应的提升.     

多晶硅太阳电池背表面刻蚀提升其性能的产线工艺研究

对比研究了产线上多晶硅太阳电池背表面刻蚀对 其光电转换性能的影响。示范性实验结果表明:多晶硅太阳电池背表面刻蚀能够改善其短路 电流, 从而相应的光电转换效 率提升了约 0．1％。依据多晶硅太阳电池背表面刻蚀前后的扫描 电镜(SEM)形貌、背表面漫 反射光谱及完整电池片外量子效率的测试结果,改进的光电转换的原因可能源于背表面刻蚀 “镜面”化有利于太阳光子在背表面内反射和改进印刷Al浆与背表面覆盖接触。背表面刻蚀 与当前晶硅电池产线工艺兼容,能够提升电池片的光电转换效率,是一种可供选择的产线升 级工艺。     

高效率n型Si太阳电池技术现状及发展趋势

提高太阳电池光电转换效率、降低光伏发电成本已成为全球光伏领域的研究热点。由于n型晶体Si具有体少子寿命长、光致衰减小等优点,非常适于制作低成本高效率太阳电池,近年来高效率n型Si太阳电池引起了人们广泛的关注。文章在论述n型Si特性的基础上,介绍了IBC结构、PERT结构、HIT结构、PERL结构和常规电池结构n晶体Si太阳电池的研究进展及产业化水平,给出了n型Si电池今后的研究方向。     

Study of injection effects on BSF silicon solar cells

The behavior of p⁺-n-n⁺ and n⁺-p-p⁺ silicon solar cells in terms of short-circuit current, open-circuit voltage, fill factor, and efficiency is studied as a function of base doping and illumination levels. A theoretical model that is valid for any injection level in the base region is used. Experimental results for cells of n-type base (in the range of 0.3 to 1000 Ω-cm) and a p-type base (0.4 to 300 Ω-cm) are presented. The theoretical model is able to explain phenomena such as the superlinearity of I_sc with concentration and the degradation of short-circuit current and efficiency at very high concentrations. These effects are seen as connected with the ohmic electric field in the base region. For the emitter saturation currents considered here, it can be concluded that, for p-type substrates, low base resistivities (≅1 Ω-cm) are necessary to achieve high efficiencies under concentrated light (≅100 suns), while for flat-array cells a particular resistivity is not required. For n-type substrates, it is found that any resistivity level can be used for both flat-array and concentrator cells     

Enhanced lateral current transport via the front N+ diffused layer of n‐type high‐efficiency back‐junction back‐contact silicon solar cells

N‐type back‐contact back‐junction solar cells were processed with the use of industrially relevant structuring technologies such as screen‐printing and laser processing. Application of the low‐cost structuring technologies in the processing of the high‐efficiency back‐contact back‐junction silicon solar cells results in a drastic increase of the pitch on the rear cell side. The pitch in the range of millimetres leads to a significant increase of the lateral base resistance. The application of a phosphorus doped front surface field (FSF) significantly reduces the lateral base resistance losses. This additional function of the phosphorus doped FSF in reducing the lateral resistance losses was investigated experimentally and by two‐dimensional device simulations. Enhanced lateral majority carrier's current transport in the front n⁺ diffused layer is a function of the pitch and the base resistivity. Experimental data show that the application of a FSF reduces the total series resistance of the measured cells with 3.5 mm pitch by 0.1 Ω cm² for the 1 Ω cm base resistivity and 1.3 Ω cm² for the 8 Ω cm base resistivity. Two‐dimensional simulations of the electron current transport show that the electron current density in the front n⁺ diffused layer is around two orders of magnitude higher than in the base of the solar cell. The best efficiency of 21.3% was obtained for the solar cell with a 1 Ω cm specific base resistivity and a front surface field with sheet resistance of 148 Ω/sq. Copyright © 2008 John Wiley & Sons, Ltd.     

The effect of doping density and injection level onminority-carrier lifetime as applied to bifacial dendritic web siliconsolar cells

The measured short-circuit current density in bifacial dendritic web silicon solar cells has been found to decrease with decreasing base resistivity, particularly under back illumination. In addition, the ratio of short-circuit current under back illumination to short-circuit current under front illumination was observed to vary with light intensity. These observations reflect the fact that the minority-carrier lifetime in the base of these cells is a function of the base resistivity and the illumination level. The dopant was assumed to play only an indirect role in determining lifetime. This decrease in lifetime is shown to follow from a distribution of defect levels in the bandgap. These levels are a consequence of extended defects that have been observed in the web material, namely oxide precipitates and the dislocation cores that they decorate. The dopant, acts only in the indirect role of moving the Fermi level over an existing background distribution of defect levels that arise from the extended defects. Assuming a parabolic distribution of defect levels in the bandgap, the minority-carrier lifetime was calculated as a function of doping density and excess carrier concentration (illumination level) using the Shockley-Reed-Hall theory. The short-circuit current densities that were calculated using these lifetimes agreed reasonably well with measured values for bifacial dendritic web silicon solar cells. The measurements were made over a range of doping densities (6×10¹⁴ to 3×10¹⁶ cm^-3) and illumination levels (0.001 to 1 sun) for both front and back illumination of the bifacial cells     

Radiation effect on the optical and electrical properties of CdSe(In)/p-Si heteroj unction photovoltaic solar cells

The efficiency and radiation resistance of solar cells are graded.They are then fabricated in the form of n-CdeSe（In）/p-Si heterojunction cells by electron beam evaporation of a stoichiomteric mixture of CdSe and In to make a thin film on a p-Si single crystal wafer with a thickness of 100μm and a resistivity of～1.5Ω·cm at a temperature of 473 K.The short-circuit current density(j_sc),open-circuit voltage(V_oc),fill factor（ff） and conversion efficiency（η） under 100 mW/cm²（AMI） intensity,are 20 mA/cm²,0.49 V,0.71 and 6%respectively. The cells were exposed to different electron doses（electron beam accelerator of energy 1.5 MeV,and beam intensity 25 mA）.The cell performance parameters are measured and discussed before and after gamma and electron beam irradiation.