Simulation analysis of the effects of a back surface field on a p-a-Si:H/n-c-Si/n+-a-Si:H heterojunction solar cell

In order to investigate the effects of a back surface field（BSF） on the performance of a p-doped amorphous silicon（p-a-Si：H）/n-doped crystalline silicon（n-c-Si） solar cell,a heterojunction solar cell with a p-a-Si：H/n-c-Si/n^＋-a-Si：H structure was designed.An n^＋-a-Si：H film was deposited on the back of an n-c-Si wafer as the BSF.The photovoltaic performance of p-a-Si：H/n-c-Si/n^＋-a-Si：H solar cells were simulated.It was shown that the BSF of the p-a-Si：H/n-c-Si/n^＋-a-Si：H solar cells could effectively inhibit the decrease of the cell performance caused by interface states.     

聚光作用下光伏电池阵列性能分析

Performance of concentrating photovoltaic/thermal system is researched by experiment and simulation calculation. The results show that the I-V curve of the GaAs cell array is better than that of crystal silicon solar cell arrays and the exergy produced by 9.51% electrical efficiency of the GaAs solar cell array can reach 68.93% of the photovoltaic/thermal system. So improving the efficiency of solar cell arrays can introduce more exergy and the system value can be upgraded. At the same time, affecting factors of solar cell arrays such as series resistance, temperature and solar irradiance also have been analyzed. The output performance of a solar cell array with lower series resistance is better and the working temperature has a negative impact on the voltage in concentrating light intensity. The output power has a -20 W/V coefficient and so cooling fluid must be used. Both heat energy and electrical power are then obtained with a solar trough concentrating photovoltaic/thermal system.     

Simulation analysis of a high efficiency GaInP/Si multijunction solar cell

The solar power conversion efficiency of a gallium indium phosphide(GaInP)/silicon(Si)tandem solar cell has been investigated by means of a physical device simulator considering both mechanically stacked and monolithic structures.In particular,to interconnect the bottom and top sub-cells of the monolithic tandem,a gallium arsenide(GaAs)-based tunnel-junction,i.e.GaAs(n+)/GaAs(p+),which assures a low electrical resistance and an optically low-loss connection,has been considered.The J–V characteristics of the single junction cells,monolithic tandem,and mechanically stacked structure have been calculated extracting the main photovoltaic parameters.An analysis of the tunnel-junction behaviour has been also developed.The mechanically stacked cell achieves an efficiency of 24.27%whereas the monolithic tandem reaches an efficiency of 31.11%under AM1.5 spectral conditions.External quantum efficiency simulations have evaluated the useful wavelength range.The results and discussion could be helpful in designing high efficiency monolithic multijunction GaInP/Si solar cells involving a thin GaAs(n+)/GaAs(p+)tunnel junction.     

Analysis of the p+/p window layer of thin film solar cells by simulation

正The application of a p~+/p configuration in the window layer of hydrogenated amorphous silicon thin film solar cells is simulated and analyzed utilizing an AMPS-ID program.The differences between p~+-p-i-n configuration solar cells and p-i-n configuration solar cells are pointed out.The effects of dopant concentration, thickness of p~+-layer,contact barrier height and defect density on solar cells are analyzed.Our results indicate that solar cells with a p~+-p-i-n configuration have a better performance.The open circuit voltage and short circuit current were improved by increasing the dopant concentration of the p~+ layer and lowering the front contact barrier height.The defect density at the p/i interface which exceeds two orders of magnitude in the intrinsic layer will deteriorate the cell property.     

种子层对微晶硅锗太阳电池的影响

Using plasma enhanced chemical vapor deposition（PECVD） at 13.56 MHz,a seed layer is fabricated at the initial growth stage of the hydrogenated microcrystalline silicon germanium(μc-Si_1-xGe_x:H) i-layer.The effects of seeding processes on the growth ofμc-Si_1-xGe_x:H i-layers and the performance ofμc-Si_1-xGe_x:H p-i-n single junction solar cells are investigated.By applying this seeding method,theμc-Si_1-xGe_x:H solar cell shows a significant improvement in short circuit current density(J_sc) and fill factor（FF） with an acceptable performance of blue response as aμc-Si:H solar cell even when the Ge content x increases up to 0.3.Finally,an improved efficiency of 7.05%is achieved for theμc-Si_0.7Ge_0.3:H solar cell.     

晶体硅聚光太阳能电池的发射极和前电极优化

The optimizations of the emitter region and the metal grid of a concentrator silicon solar cell are illustrated. The optimizations are done under 1 sun,100 suns and 200 suns using the 2D numerical simulation tool TCAD software.The optimum finger spacing and its range decrease with the increase in sheet resistance and concentration ratio.The processes of the diffusion and oxidization in the manufacture flow of the silicon solar cells were simulated to get a series of typical emitter dopant profiles to optimize.The efficiency of the solar cell under 100 suns and 200 suns increased with the decrease in diffusion temperature and the increase in oxidation temperature and time when the diffusion temperature is lower than or equal to 865℃.The effect of sheet resistance of the emitter on series resistance and the conversion efficiency of the solar cell under concentration was discussed.     

Optimization of n/i and i/p buffer layers in n-i-p hydrogenated microcrystalline silicon solar cells

Hydrogenated microcrystalline silicon （μc-Si：H） intrinsic films and solar cells with n-i-p configuration were prepared by plasma enhanced chemical vapor deposition （PECVD）. The influence of n/i and i/p buffer layers on the μc-Si：H cell performance was studied in detail. The experimental results demonstrated that the efficiency is much improved when there is a higher crystallinity at n/i interface and an optimized a-Si：H buffer layer at i/p interface. By combining the above methods, the performance of μc-Si：H single-junction and a-Si：H/μc-Si：H tandem solar cells has been significantly improved.     

Preface to the Special Topic on Perovskite Solar Cells

Halide perovskite materials were discovered about one hundred years ago,but the application of this material in solar cells only can be traced back to 2009,when the first perovskite solar cells (PSCs) were demonstrated by Miyasaka et al.in a dye sensitized solar cell configuration showing 3.8％ power conversion efficiency.After seven years of intensive efforts,including controlling the perovskite film crystal growth,perovskite/transport layers interfaces and device architecture,the laboratory efficiency of perovskite solar cells has reached 22.1％ by Seok et al.from South Korea in early 2016.     

CZ法硅晶体生长过程中热输运和流体流动的数值研究

A global analysis of heat transfer and fluid flow in a real Czochralski single silicon crystal furnace is developed using the FLUENT package.Good agreement was obtained for comparisons of the power and crystal growth speed between the simulation and experimental data,and the effect of the length of the crystal on heat transfer and fluid flow was analyzed.The results showed that T_max increases and its location moves downward as the crystal length increases.The flow pattern in the melt does not change until the crystal grows to 900 mm.As the crystal length increases,the flow pattern in the first gas area only changes when the crystal length is less than 700 mm,but the flow pattern in the second area changes throughout the growth process.     

Study of 2-D photon crystal Fano slab filters for biological sensing

A new compact optical Fano filter suitable for biological sensing is proposed, which patterns photon crystal in single crystalline silicon nanomembranes （SiNMs） and transferring onto transparent glass substrates. The effects of air hole size and silicon thickness on the transmission characteristics of new filter are numerically investigated by using three-dimensional finite-difference time-domain （FDTD） technique, the spectral response is also studied by back-filling bio-liquid. The results show that the dip wavelength wil shift toward longer wavelength by either reducing air hole radius or filling bioliquid. The number of dips will inereasc with the increase of silicon thickness. The size of proposed filter can be less than I mm^2.     

Effect of zinc impurity on silicon solar-cell efficiency

Zinc is a major residue impurity in the preparation of solar-grade silicon material by the zinc vapor reduction of silicon tetrachloride. This paper projects that in order to get a 17-percent AM1 cell efficiency for the Block IV module of the Low-Cost Solar Array Project,¹the concentration of the zinc recombination centers in the base region of silicon solar cells must be less than 4 × 10¹¹Zn/cm³in the p-base n+/p/p+ cell and 7 × 10¹¹Zn/cm³in the n-Base p+/n/n+ cell for a base dopant impurity concentration of 5 × 10¹⁴atoms/cm³. If the base dopant impurity concentration is increased by a factor of 10 to 5 × 10¹⁵atoms/cm³, then the maximum allowable zinc concentration is increased by a factor of about two for a 17-percent AM1 efficiency. The thermal equilibrium electron and hole recombination and generation rates at the double-acceptor zinc centers are obtained from previous high-field measurements as well as new measurements at zero field described in this paper. These rates are used in the exact dc-circuit model to compute the projections.     

Optimum flash lamp annealing conditions for fabrication of low dose ion-implanted Si solar cells

A method to fabricate silicon solar cells was developed around low dose (nonamorphized) ion implantation and Xe flash lamp annealing under assist heating (350-550°C). Solar cells fabricated by low dose¹¹B+ (p+/n-type cell) and³¹p+ (n+/p-type cell) implantation and flash lamp annealing showing a high efficiency of about 10.4 percent (AM2) without AR coating and BSF structures. The results were compared with those of high dose implanted cells reported by us previously (in this transaction). Effects of assist heating temperature were also examined.     

Use of tin oxide as an inexpensive antireflection coating for p on n polycrystalline silicon solar cells

The potential of tin oxide as an inexpensive antireflection (AR) coating for polycrystalline silicon solar cells has been investigated. Undoped tin oxide films of a desired thickness were deposited over p on n polycrystalline silicon solar cells by spray pyrolysis of an alcoholic solution of hydrated stannic chloride at 500°C. Evaluation of cell performance before and after this AR coating showed that the AR coating is highly compatible with the polycrystalline silicon solar cells. About 40-50 percent improvement in the short-circuit current of p on n polycrystalline cells has been measured. The coating may be highly suited to large-scale production of low-cost polycrystalline silicon solar cells for terrestrial application.     

UV‐nano‐imprint lithography technique for the replication of back reflectors for n‐i‐p thin film silicon solar cells

Texturing of interfaces in thin film silicon solar cells is essential to enhance the produced photocurrent and thus the efficiencies. A UV nano‐imprint‐lithography (UV‐NIL) replication process was developed to prepare substrates with textures that are suitable for the growth of n‐i‐p thin film silicon solar cells. Morphological and optical analyses were performed to assess the quality of the replicas. A comparison of single junction amorphous solar cells on the original structures and on their replicas on glass revealed good light trapping and excellent electrical properties on the replicated structures. A tandem amorphous silicon/amorphous silicon (a‐Si/a‐Si) cell deposited on a replica on plastic exhibits a stabilized efficiency of 8.1% and a high yield of 90% of good cells in laboratory conditions. It demonstrates the possibility to obtain appropriate structure on low cost plastic substrate. Copyright © 2010 John Wiley & Sons, Ltd.     

Simulation analysis of the effects of a back surface field on a p-a-Si:H/n-c-Si/n+-a-Si:H heterojunction solar cell

In order to investigate the effects of a back surface field (BSF) on the performance of a p-doped amorphous silicon (p-a-Si:H)/n-doped crystalline silicon (n-c-Si) solar cell, a heterojunction solar cell with a p-a-Si:H/nc-Si/n+-a-Si:H structure was designed. An n+-a-Si:H film was deposited on the back of an n-c-Si wafer as the BSF.The photovoltaic performance of p-a-Si:H/n-c-Si/n+-a-Si:H solar cells were simulated. It was shown that the BSF of the p-a-Si:H/n-c-Si/n+-a-Si:H solar cells could effectively inhibit the decrease of the cell performance caused by interface states.     

空间太阳电池硅单晶的辐射效应及加固

概述了硅太阳电池和硅单晶在空间高能粒子辐射下性能的变化及采用掺锡、掺锂提高太阳电池用硅单晶抗辐射性能的原理和方法。     

不同工作温度下a-Si(n)/c-Si(p)/uc-Si(p )异质结太阳能电池微晶硅背场的模拟计算与优化

采用Afors-het太阳能电池异质结模拟软件,模拟了在不同工作温度下微晶硅背场对a-Si(n)/c-Si(p)异质结太阳能电池性能的影响。结果表明,随着背场带隙的增加,开路电压和转化效率都增大。随着背场掺杂浓度的增加,开路电压、填充因子和转化效率都在不断地增加;随着背场厚度的增加,电池性能有所下降。随着电池工作温度的上升,微晶硅背场所对应的最佳浓度掺杂值和最佳厚度值变化不大。但是随着温度的上升,微晶硅背场所对应的最佳带隙值有明显的右移趋势。实验结果为电池的商业化生产提供了实验参数。     

Bifacial silicon solar cells with 21·3% front efficiency and 19·8% rear efficiency

We introduced a triode structure with p–n junctions on both sides into single‐crystalline bifacial silicon solar cells in order to improve solar cell performance. These fabricated bifacial silicon solar cells have an energy conversion efficiency of 21·3% under front 1 sun illumination (the standard 1 kW/m² AM 1·5 global spectrum at 25°C) and 19·8% under rear 1 sun illumination tested at the Japan Quality Assurance Organization. The total of the front and rear conversion efficiencies is the highest ever reported for bifacial silicon solar cells. Copyright © 2000 John Wiley & Sons, Ltd.