Local leakage current behaviours of BiFeO3 films

The leakage current behaviours of polycrystalline BiFeO₃ thin films are investigated by using both conductive atomic force microscopy and current-voltage characteristic measurements. The local charge transport pathways are found to be located mainly at the grain boundaries of the films. The leakage current density can be tuned by changing the post-annealing temperature, the annealing time, the bias voltage and the light illumination, which can be used to improve the performances of the ferroelectric devices based on the BiFeO₃ films. A possible leakage mechanism is proposed to interpret the charge transports in the polycrystalline BiFeO₃ films.     

掺杂Rhodamine 6G的平面波导型PMMA聚光器研制

通过聚光波导提高光的转换和收集效率,是提高太阳能电池效率、减少电池用量、降低光伏发电系统成本的重要途径。利用PMMA作为波导基质材料,Rhodamine 6G(罗丹明6G)作为荧光染料,通过涂覆方法,在表面积为50 mm×50 mm、厚度为5 mm的洁净PMMA衬底上制备出了荧光层厚度约为32 μm的平面波导型聚光器,并研究了荧光染料的掺杂浓度对其聚光比和光伏性能的影响。结果表明,当掺杂浓度为0.250%时,聚光器的聚光比和器件的光伏性能达到了最优,分别为0.45%和0.49%。     

基于LR305的平面荧光太阳能聚光波导研制

光伏发电是目前太阳能最佳的利用方式之一,但发电成本高。利用聚光结构提高光的转换和收集效率,是提高太阳能电池效率、减少电池用量、降低光伏发电系统成本的重要途径。以Lumogen F Red 305 (LR305) 染料作为荧光材料,将其掺杂到PMMA中,通过本体聚合法制作出尺寸为50 mm×50 mm×5 mm的PMMA平面荧光太阳能聚光波导,对其光学特性进行表征,同时将太阳能电池粘贴到聚光波导的输出端面,通过测试平面荧光太阳聚光波导对太阳能电池性能的影响研究了荧光太阳能聚光波导的聚光特性。