Numerical Study on Open-Circuit Voltage of Single Layer Organic Solar Cells with Schottky Contacts: Effects of Molecular Energy Levels, Temperature and Thickness

We numerically investigate the effects of the exciton generation rate G, temperature T, the active layer thickness d and the position of LUMO level EL related to the cathode work function Wc at a given energy gap on the opencircuit voltage Voc of single layer organic solar cells with Schottky contact. It is demonstrated that open-circuit voltage increases concomitantly with the decreasing cathode work function Wc for given anode work functions and exciton generation rates. In the case of given cathode and anode work functions, the open-circuit voltage first increases with the exciton generation rate and then reaches a saturation value, which equals to the builtin voltage. Additionally, it is worth noting that a significant improvement to Voc could be made by selecting an organic material which has a relative high LUMO level （low ｜EL｜ value）. However, Voc decreases as the temperature increases, and the decreasing rate reduces with the enhancement of exeiton generation rate. Our study also shows that it is of no benefit to improve the open-circuit voltage by increasing the device thickness because of an enhanced charge recombination in thicker devices.     

Electrical Property of Infrared-Sensitive InAs Solar Cells

InAs infrared-sensitive solar cells are fabricated by using the films grown by the liquid phase epitaxy technique. The film microstructures are characterized by x-ray diffraction and scanning electronic microscopy. The current-voltage characteristics of the solar cells in the dark and under AM1.5 illumination at 300 K and 77 K are discussed. The conversion efficiency of p-InAs/n-sub InAs cells decreases when the thickness of the p-type film changes from 1.7 μm to 3.5 μm, which is caused by the reduced effective photons near p？n junction. The p-InAs/n-InAs/n-sub InAs solar cell with the conversion efficiency of 7.43% in 1-2.5 μm under AM1.5 at 77 K is obtained. The short circuit current density increases dramatically with decreasing temperature due to the weakened effect of phonon scattering.     

A Novel Ce3＋/Tb3＋ Codoped Phosphate Glass as Down-Shifting Materials for Enhancing Efficiency of Solar Cells

For the purpose of improving conversion efficiency of solar cells by applying the effect of the wavelength conversion of rare earth ions, photo-luminescence and excitation spectrums of Ce3＋-Tb3＋ doped phosphate glass are investigated. Results show that incorporating Ce3＋ ions to Tb3＋-doped phosphate glass can greatly increase the absorption coefficient in the range 300-400 nm and then the energy transfer （ET） from Ce3＋ to Tb3＋ occurs. In addition, increasing Tb3＋ concentration in Ce3＋/Tb3＋ co-doped phosphate glass can greatly enhance the ET efficiency and 545 nm emission intensity. This shows that Ce3＋/Tb3＋ co-doped phosphate glass would be a promising down-shifting material for enhancing the efficiency of solar cells.     

金属诱导低温制备多晶硅薄膜工艺新进展

多晶硅薄膜由于兼具稳定性、高光敏性、便于大面积沉积等优势成为目前光伏领域的研究热点.本文综述了近几年金属诱导非晶硅薄膜晶化的新工艺,介绍了各种工艺条件对多晶硅薄膜材料的结构、金属含量的调控规律.最后展望了未来的发展趋势.     

Cu掺杂对CdS薄膜结构、光致发光及CdS/CdTe电池性能的影响

采用化学浴沉积(CBD)法在FTO(SnO2∶F)/Glass衬底上制备了Cu掺杂的CdS薄膜.用电感耦合等离子体-原子发射光谱(ICP-AES)测得不同Cu掺杂浓度的薄膜中Cu/Cd原子比分别为0.5％、1.5％、5％.分别用X射线衍射(XRD)、扫描电镜(SEM)、光致发光谱(PL)、紫外-可见-近红外反射透射谱对薄膜样品进行表征.研究了Cu掺杂对CdS薄膜的晶体结构,微观形貌以及体内点缺陷的影响.用Cu掺杂的CdS薄膜作为N型层制备CdTe太阳能电池,研究了CdS层中Cu对电池性能的影响.     

硅太阳电池表面多孔硅的制备与作用

利用电化学方法在硅太阳能电池的金字塔上面刻蚀一层多孔硅,研究多孔硅对硅表面反射率、光电转换量子效率的影响以及氧化对不同波长的光电转换量子效率的影响。研究发现氢氟酸浓度对反射率没有明显的影响,而电化学反应时间可以调制反射率最低波长点,最终获得综合反射率低至2%的优质减反效果。多孔硅的存在使得300～500 nm的光电转换量子效率降低,500 nm以上长波的光电转换量子效率增加。氧气氛围中的快速退火能够有效降低少数载流子的表面复合,从而增加短波段的光电转换量子效率。     

1954年4月25日：贝尔实验室示范了第一个实用的硅太阳能电池

 可以将阳光转换成电流的太阳能电池开始出现于一百多年前,但早期的太阳能电池效率太低,所以并无多大用处。 1954年4月,美国贝尔实验室的研究员才示范了第一个实用的硅太阳能电池。     

2,6-双(三甲基锡)-4,8-双(2-乙基己氧基)苯并[1,2-b∶4,5-b']二噻吩的合成与多核NMR研究

以苯并[1,2-b∶4,5-b´]二噻吩-4,8-二酮为原料合成了一种聚合物太阳能电池材料的单体2,6-双(三甲基锡)-4,8-双(2-乙基己氧基)苯并[1,2-b∶4,5-b´]二噻吩. 通过多核1D和2D NMR技术（包括1D ¹H、¹³C、¹¹⁹Sn、¹¹⁷Sn NMR、DEPT、选择性1D TOCSY及2D¹H-¹H COSY、gHSQC、gHMBC）表征了目标分子结构,完成了 ¹H、¹³C、¹¹⁹Sn 与¹¹⁷Sn NMR化学位移归属,并探讨了该化合物的NMR谱线特征.     

Thermal modeling optimization and experimental validation for a single, concentrator solar cell system with a heat sink

A single concentrator solar cell model with a heat sink is established to simulate the thermal performance of the system by varying the number, height, and thickness of fins, the base thickness and thermal resistance of the thermal conductive adhesive. Influence disciplines of those parameters on temperatures of the solar cell and heat sink are obtained. With optimized number, height and thickness of fins, and the thickness values of base of 8, 1.4 cm, 1.5 mm, and 2 mm, the lowest temperatures of the solar cell and heat sink are 41.7℃ and 36.3℃ respectively. A concentrator solar cell prototype with a heat sink fabricated based on the simulation optimized structure is built. Outdoor temperatures of the prototype are tested. Temperatures of the solar cell and heat sink are stabilized with time continuing at about 37℃-38℃ and 35℃-36℃ respectively, slightly lower than the simulation results because of effects of the wind and cloud. Thus the simulation model enables to predict the thermal performance of the system, and the simulation results can be a reference for designing heat sinks in the field of single concentrator solar cells.