光纤太阳光照明系统中聚光装置的设计

将太阳光经传能光纤传输到室内进行照明是太阳能利用的新发展,而将太阳光耦合到传能光纤中是这项技术的一个难点。在分析塑料光纤的特点和各种聚光技术的基础上,提出一种把太阳光耦合进传能光纤中进行传输的聚光装置。根据非球面透镜垂轴球差小的特点把太阳光会聚到很小的光点,再利用长度约为1/4节距的自聚焦透镜改变光线的数值孔径使其满足光纤的数值孔径,通过一个计算公式来计算最佳的自聚焦透镜长度,实现非球面透镜和自聚焦透镜的最佳组合,把太阳光以较高的耦合效率耦合进塑料光纤。最后在理论上验证了此装置的可行性。     

Reveal the large open-circuit voltage deficit of all-inorganicCsPbIBr2 perovskite solar cells

Due to excellent thermal stability and optoelectronic properties, all-inorganic perovskite is one of the promising candidates to solve the thermal decomposition problem of conventional organic—inorganic hybrid perovskite solar cells (PSCs), but the larger voltage loss (V_loss) cannot be ignored, especially CsPbIBr₂, which limits the improvement of efficiency. To reduce V_loss, one promising solution is the modification of the energy level alignment between the perovskite layer and adjacent charge transport layer (CTL), which can facilitate charge extraction and reduce carrier recombination rate at the perovskite/CTL interface. Therefore, the key issues of minimum V_loss and high efficiency of CsPbIBr₂-based PSCs were studied in terms of the perovskite layer thickness, the effects of band offset of the CTL/perovskite layer, the doping concentration of the CTL, and the electrode work function in this study based on device simulations. The open-circuit voltage (V_oc) is increased from 1.37 V to 1.52 V by replacing SnO₂ with ZnO as the electron transport layer (ETL) due to more matching conduction band with the CsPbIBr₂ layer.