Modeling and Simulation of Heterojunction Solar Cell with Mono Crystalline Silicon

The monocrystalline silicon is a promising material that could be used in solar cells that convert light into electricity. Although the cost of ordinary silicon (Si) solar cells has decreased significantly over the past two decades, the conversion efficiency of these cells has remained relatively high. While solar cells have a great potential as a device of renewable energy, the high cost they incur per Watt continues to be a significant barrier to their widespread implementation. As a consequence, it is vital to conduct research into alternate materials that may be used in the construction of solar cells. The heterojunction solar cell (HJSC), which is based on n-type zinc oxide (n-ZnO) and p-type silicon (p-Si), is one of the numerous alternatives of the typical Si single homojunction solar cell. There are many deficiencies that can be found in the published research on n-ZnO/p-Si heterojunction solar cell. Inconsistencies in the stated value of open circuit voltage (Voc) of the solar cell are one example of deficiency. The absence of a full theoretical study to evaluate the potential of the solar cell structure is another deficiency that can be found in these researches. A lower value of experimentally obtained VOC in comparison to the theoretical prediction based on the band-gap between n-ZnO and p-Si. There needs to be more consensus among scientists regarding the optimal conditions for the growth of zinc oxide. Many software’s are available for simulating and optimizing the solar cells based on these parameters. For this purpose, in this dissertation, I provide computational results relevant to n-ZnO/p-Si HJSC to overcome deficiencies that have been identified. While modeling and simulating the potential of the solar cell structure with AFORS-HET, it is essential to consider the constraints that exist in the real world. AFORS-HET was explicitly designed to mimic the multilayer solar cell arrangement. In AFORS-HET, we can add up to seven layers for solar cell layout. By using this software, we can figure out the open circuit voltage (VOC), the short circuit current (JSC), the quantum efficiency (QE, %), the heterojunction energy band structure, and the power conversion efficiency (PCE).

Analysis of each branch current of serial solar cells by using an equivalent circuit model

In this paper, based on the equivalent single diode circuit model of the solar cell, an equivalent circuit diagram for two serial solar cells is drawn. Its equations of current and voltage are derived from Kirchhoff＇s current and voltage law. First, parameters are obtained from the I-V （current-voltage） curves for typical monocrystalline silicon solar cells （125 mmx 125 mm）. Then, by regarding photo-generated current, shunt resistance, serial resistance of the first solar cell, and resistance load as the variables. The properties of shunt currents （Ishl and Ish2）, diode currents （/D1 and/]：）2）, and load current （IL） for the whole two serial solar cells are numerically analyzed in these four cases for the first time, and the corresponding physical explanations are made. We find that these parameters have different influences on the internal currents of solar cells. Our results will provide a reference for developing higher efficiency solar cell module and contribute to the better understanding of the reason of efficiency loss of solar cell module.

Influence of optical interference and carrier lifetime on the short circuit current density of organic bulk heterojunction solar cells

Based on simple analytical equations, short circuit current density （Jsc） of the organic bulk heterojunction solar cells has been calculated. It is found that the optical interference effect plays a very important role in the determination of Jsc; and obvious oscillatory behaviour of Jsc was observed as a function of thickness. At the same time, the influence of the carrier lifetime on Jsc also cannot be neglected. When the carrier lifetime is relatively short, Jsc only increases at the initial stage and then decreases rapidly with the increase of active layer thickness. However, for a relatively long carrier lifetime, the exciton dissociation probability must be considered, and Jsc behaves wave-like with the increase of active layer thickness. The validity of this model is confirmed by the experimental results.

Open-circuit voltage analysis of p-i-n type amorphous silicon solar cells deposited at low temperature

This paper identifies the contributions of p-a-SiC：H layers and i-a-Si：H layers to the open circuit voltage of p-i-n type a-Si：H solar cells deposited at a low temperature of 125℃. We find that poor quality p-a-SiC：H films under regular conditions lead to a restriction of open circuit voltage although the band gap of the i-layer varies widely. A significant improvement in open circuit voltage has been obtained by using high quality p-~SiC：H films optimized at the ＂low-power regime＂ under low silane flow rates and high hydrogen dilution conditions.

Improvement of the Open Circuit Voltage of CZTSe Thin-Film Solar Cells by Surface Sulfurization Using SnS

The objective of this study is to find an effective method to improve Voc without Jsc loss for Cu2ZnSnSe4 （CZTSe） thin film solar cells, which have been fabricated by the one step co-evaporation technique. Surface sulfurization of CZTSe thin films is carried out by using one technique that does not utilize toxic H2S gas; a sequential evaporation of SnS after CZTSe deposition and the annealing of CZTSe thin films in selenium vapor. A Cu2ZnSn（S, Se）4 （CZTSSe） thin layer is grown on the surface of the CZTSe thin film after the annealing. The conversion efficiency of the completed device is improved due to the enhancement of Voc, which could be attributed to the formation of a hole-recombination barrier at the surface or the passivation of the surface and grain boundary by S incorporation.

An Approach to Equivalent Circuit Modelling of Inverted Organic Solar Cells

A low temperature sol-gel process was used to fabricate zinc-oxide and yttrium-doped zinc oxide layers. These zinc-oxide and yttrium-doped ZnO films were used as electron transport layers in conjunction with P3HT and PC16BM type solar cells. It was demonstrated that annealing and doping of electron transport layer influenced the overall organic solar cells performance. Anneals of ~ 150?C provided the highest device performance. Compared to the undoped zinc oxide, the device with yttrium doped zinc oxide layers showed improved efficiency by about 30%. Furthermore an equivalent circuit was proposed to understand the connection between the electrical and optical characteristics of the device. Comparisons between the simulated and experimental current-voltage(I-V) curves displayed only a 1.2% variation between the curves. Clearly, our experimental and simulated studies provide new insight on the equivalent circuit models for inverted organic solar cells and further improvement on photovoltaic efficiency.

Equivalent Circuit Modification for Organic Solar Cells

In this work, a newly fabricated organic solar cell based on a composite of fullerene derivative [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) and regioregular poly (3-hexylthiophene) (P3HT) with an added interfacial layer of AgOx in between the PEDOT:PSS layer and the ITO layer is investigated and an equivalent circuit model is proposed for the device. Incorporation of the AgOx interfacial layer shows an increase in fill factor (by 33%) and power conversion efficiency (by 28%). Moreover, proper correlation has been achieved between the experimental and simulated I-V plots. The simulation shows that device characteristics can be explained with accuracy by the proposed model.

Retraction:Modeling Electrical Characteristics of a pn-Junction Silicon Solar Cell Using PSpice

Short Retraction Notice The article has been retracted due to the investigation of complaints received against it. The substantial portions of the text came from Luis Casta?er and Santigo Silvestre, " Modelling photovoltaic systems using PSpice".The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. This paper published in Vol.3 No.2 133-138, 2012, has been removed from this site.

Organic dyes based on triphenylamine for dye-sensitized solar cells:Structure–property relationships

Three new organic dyes based on triphenylamine with a structure of A-D-A-D-A (D1), A-D-A (D2) and D-A (D3) were designed, theoretically calculated and synthesized for dye-sensitized solar cells. Dye D1 exhibits a broader absorption than D2 and D3, due to the intramolecular charge transfer between the donor triphenylamine and the acceptor benzothiadiazole. Dye D1 exhibits a lower HOMO and a lower LUMO than D2 and D3 due to the electron-withdrawing benzothiadiazole. The number of anchoring group cyanoacrylic acid has no obvious influence on absorption and energy levels of D2 and D3. The LUMO of D1 locates on benzothiadiazole rather than cyanoacrylic acid anchoring groups, while the LUMOs of D2 and D3 are localized on cyanoacrylic acid. D2 and D3 give higher short-circuit current density than D1. D3 with one anchoring group gives the highest open-circuit voltage. Consequently, the D3-based device gives the highest efficiency. © 2016 Science Press

Simulation of a-Si:H/c-Si heterojunction solar cells: From planar junction to local junction

In order to obtain higher conversion efficiency and to reduce production cost for hydrogenated amorphous silicon/crystalline silicon(a-Si:H/c-Si) based heterojunction solar cells, an a-Si:H/c-Si heterojunction with localized p–n structure(HACL) is designed. A numerical simulation is performed with the ATLAS program. The effect of the a-Si:H layer on the performance of the HIT(heterojunction with intrinsic thin film) solar cell is investigated. The performance improvement mechanism for the HACL cell is explored. The potential performance of the HACL solar cell is compared with those of the HIT and HACD(heterojunction of amorphous silicon and crystalline silicon with diffused junction) solar cells.The simulated results indicate that the a-Si:H layer can bring about much absorption loss. The conversion efficiency and the short-circuit current density of the HACL cell can reach 28.18% and 43.06 m A/cm^2, respectively, and are higher than those of the HIT and HACD solar cells. The great improvement are attributed to(1) decrease of optical absorption loss of a-Si:H and(2) decrease of photocarrier recombination for the HACL cell. The double-side local junction is very suitable for the bifacial solar cells. For an HACL cell with n-type or p-type c-Si base, all n-type or p-type c-Si passivating layers are feasible for convenience of the double-side diffusion process. Moreover, the HACL structure can reduce the consumption of rare materials since the transparent conductive oxide(TCO) can be free in this structure. It is concluded that the HACL solar cell is a promising structure for high efficiency and low cost.

Electrical Performance Study of a Large Area Multicrystalline Silicon Solar Cell Using a Current Shunt and a Micropotentiometer

In this paper, a new technique using a Current Shunt and a Micropotentiometer has been used to study the electrical performance of a large area multicrystalline silicon solar cell at outdoor conditions. The electrical performance is mainly described by measuring both cell short circuit current and open circuit voltage. The measurements of this cell by using multimeters suffer from some problems because the cell has high current intensity with low output voltage. So, the solar cell short circuit current values are obtained by measuring the voltage developed across a known resistance Current Shunt. Samples of the obtained current values are accurately calibrated by using a Micropotentiometer (μpot) thermal element (TE) to validate this new measuring technique. Moreover, the solar cell open circuit voltage has been measured. Besides, the cell output power has been calculated and can be correlated with the measured incident radiation.

Temperature Effects on the Electrical Performance of Large Area Multicrystalline Silicon Solar Cells Using the Current Shunt Measuring Technique

The temperature effects on the electrical performance of a large area multicrystalline silicon solar cell with back-contact technology have been studied in a desert area under ambient conditions using the current shunt measuring technique. Therefore, most of the problems encountered with traditional measuring techniques are avoided. The temperature dependency of the current shunt from 5oC up to 50oC has been investigated. Its temperature coefficient proves to be negligible which means that the temperature dependency of the solar cell is completely independent of the current shunt. The solar module installed in a tilted position at the optimum angle of the location, has been tested in two different seasons (winter and summer). The obtained solar cell short circuit current, open circuit voltage and output power are correlated with the measured incident radiation in both seasons and all results are discussed.

抗氧化小分子体掺杂对锡铅钙钛矿太阳电池性能的影响

锡铅钙钛矿中存在各种缺陷,且Sn^(2+)容易被氧化成Sn^(4+),从而导致太阳电池的转换效率和稳定性较差。研究发现4-香豆酸(p-C)的引入可显著改变薄膜的表面形貌、有效提高结晶性,且抑制Sn^(2+)的氧化,有利于提高钙钛矿层与传输层之间的能级匹配度。通过对钙钛矿光吸收层的缺陷进行钝化,可显著提升太阳电池的光电特性。最终,锡铅钙钛矿太阳电池的开路电压提升65mV,光电转换效率由18.14%提升至20.37%,并且电池稳定性得到显著提升。

一种柔性太阳电池阵电传输解决方案

柔性太阳电池阵由于其质量轻、收拢体积小、可重复展收等特点,具有极大的创新性和前瞻性,是目前和今后极具竞争力的太阳电池阵构型。针对目前柔性太阳电池阵收拢和折叠特性,传统电缆束和电连接器已经不再适用,急需寻找一种新型薄型结构电传输解决方案。提出了一种柔性电缆电传输方案,这种柔性电缆具有传输功率大、质量轻、收拢体积小、可折叠等特点,非常适合作为大面积、大功率的柔性太阳阵电传输的主方式,可为未来新型太阳电池阵的设计提供新方向、设计参考和技术支撑。

基于萘核的A-D-A型非稠环受体合成及其高开路电压有机太阳能电池应用

为获得高性能、低成本、结构简单的非稠环电子受体分子,拓展其商业化应用的范围,以3,7-二溴萘-2,6-二醇和2,6-二溴萘-1,5-二醇为原料,通过烷基化反应、Stille偶联、Knoevenagel缩合反应等合成了两个异构化非稠环小分子电子受体26NO4F和15NO4F,并对其光学吸收、能级、热性能、光伏器件与形貌等进行表征。研究结果表明:在有机光伏器件中,使用PM7作为给体聚合物,PM7:26NO4F和PM7:15NO4F器件的开路电压(Voc)均超过1.0 eV,但PM7:26NO4F器件具备更高的短路电流(Jsc)和填充因子(FF),其光电转化效率(PCE)为6.01%,高于PM7:15NO4F器件的5.05%。提出一种基于萘核的高Voc电子受体分子设计思路,揭示了烷氧基取代位置对非稠环电子受体性能的影响。

不同测试方法对晶硅电池片短路电流影响的原因探究

晶硅电池认证时,电流-电压特性参数为重要参数,对光电转换效率、填充因子等参数影响较大。目前,该参数测试主要包括推导法、两步法和丝线法,且得到的短路电流均不相同。本文采用不同的测试方法,对晶硅电池片短路电流影响的原因进行探究。实验证明:探针排和丝线覆盖待测电池、探针排类型及无影探针,对电池的遮挡等均会对短路电流产生影响。该实验和分析结果可为测试机构或实验室的不同测试方法提供理论依据和参考。

便携式电子产品光伏充电器硬件电路设计及系统调试

为解决智能手机、数码相机等便携式电子产品的户外充电需求,光伏充电器应运而生。光伏充电器的硬件部分包括太阳能电池板、蓄电池以及各类电路,该文重点对光伏充电器硬件电路的设计与调试展开研究分析。首先介绍单片机主控电路、电源电路、充电电路与蓄电池温度检测电路的设计要点,随后对太阳能电池以及各类电路进行调试。结果表明,太阳能电池的光生电流和光生电压与光照强度成正比;使用Multisim仿真软件进行电路仿真,充电电路的输出电压为稳定的5 V,经过稳压电路处理后以4.2 V电压向蓄电池充电。温度检测电路可以在蓄电池满电后自动断开、避免过充,保护蓄电池。

(NH_(4))_(2)S修饰SnO_(2)/钙钛矿界面对钙钛矿太阳能电池性能的影响

为了降低电子传输层(Electron transport layer,ETL)与钙钛矿层之间的界面缺陷态密度,通过旋涂法在氧化铟锡(Indium tin oxide,ITO)透明导电玻璃上制备一层SnO_(2)电子传输层,并在其上表面旋涂(NH_(4))_(2)S以修饰SnO_(2)和钙钛矿光吸收层之间的界面。通过X射线光电子能谱、扫描电子显微镜、电化学阻抗谱等表征手段分析(NH_(4))_(2)S修饰对钙钛矿太阳能电池(Perovskite solar cells,PSCs)光电性能的影响。结果表明:NH_(4)^(+)降低了SnO_(2)的表面羟基(—OH)缺陷态密度,增强了界面的疏水性,减少了钙钛矿的形核位点,增大了钙钛矿晶粒;S^(2-)填补了SnO_(2)表面的氧空位(OV),同时部分S^(2-)还与未配位Pb^(2+)连接减少界面处Pb缺陷,抑制了界面处载流子复合;经过(NH_(4))_(2)S的修饰,PSCs开路电压从1.07 V提高到1.11 V,光电转化效率达到了20.53%。(NH_(4))2S修饰后的PSCs具有更高的光电转化效率、更好的长期稳定性。该研究可为PSCs商业化提供新的思路。

基于多元宇宙优化算法的光伏发电MPPT控制算法

针对局部阴影引起的光伏阵列多峰值的输出特性,传统的单峰值MPPT算法已无法适用,为寻得全局最优解,将参数设置简单、易于理解的多元宇宙优化算法原理应用于光伏发电的多峰值MPPT模块中。通过仿真分析,证明了基于多元宇宙优化算法的MPPT控制模型能较快地实现全局最大功率点的跟踪,具有更好的收敛速度和精度。该算法能有效解决光伏电站中多峰值功率点的问题,减少寻优过程的功率损耗,从而提高光电转换率,为实际工程带来重要的经济效益。

Sb_(2)Se_(3)-Sb_(2)S_(3)两端叠层薄膜太阳能电池

设计并制备一种全锑基两端叠层薄膜太阳能电池,其结构为ITO/CdS/Sb_(2)S_(3)/Au/ZnO/Sb_(2)Se_(3)/Au.通过快速热蒸发法制备Sb_(2)Se_(3)和Sb_(2)S_(3)薄膜,该薄膜具有良好的结晶性.测试表明,器件中各层薄膜的能级互相匹配,并且可实现光谱的分段利用.Sb_(2)Se_(3)-Sb_(2)S_(3)两端叠层电池的光电转换效率达到3.25%,其开路电压为0.98 V,可基本实现开压叠加.