Factors influencing the performance of paintable carbon-based perovskite solar cells fabricated in ambient air

To date, many efforts have been made to improve the performance of paintable carbon-based(PC-based) perovskite solar cells(PSCs). Though great progress has been achieved, their power conversion efficiencies are still relatively low compared with hole-transport-materials-based PSCs. General research on influencing factors of performance in PC-based PSCs is still insufficient. In this work, PC-based PSCs were fabricated in ambient air and four groups of controlled experiments were performed in which the PbI_2 layers were prepared with or without antisolvent extraction treatment. These four groups of experiments were designed to find out the effect of different influencing factors on PC-based PSCs performance,for example, PbI_2 residual, the surface morphology of the perovskite film, the surface roughness of the perovskite film, and the contact status of the perovskite/carbon electrode interface. With a systematic analysis, we demonstrated that the contact status of the perovskite/carbon electrode interface played a vital role in PC-based PSCs, and a flat, smooth perovskite surface could help to improve this contact status significantly. Besides, on the precondition of a poor contact interface, no PbI_2 residual and a good surface morphology only brought limited benefits to the performances of PC-based PSCs.     

以B-γ-CsSnI3为光吸收层的平面异质结钙钛矿太阳能电池的模拟优化

采用AFORS-HET软件对以B-γ-CsSnI3作为光吸收层的平面异质结钙钛矿太阳能电池结构进行了模拟优化,其中TiO2作为电子传输层,Spiro-OMeTAD作为空穴传输层,讨论了钙钛矿太阳能电池光吸收层以及空穴传输层的各种参数对太阳能电池性能的影响.模拟优化得到B-γ-CsSnI3的PSCs最佳性能参数为:Voc=1.18 V,Jsc=24.48 mA/cm2,FF=80.04;,PCE=23.15;,效率虽略低于以CH3NH3PbI3作为光吸收层的钙钛矿太阳能电池,但考虑铅的毒性和钙钛矿电池的稳定性,以B-γ-CsSnI3作为光吸收层的PSCs将具有更好的应用前景.     

硒化镉纳米线在应力作用下的第一性原理研究

基于密度泛函理论的第一性原理计算分析了不同横向尺寸的硒化镉(cdse)纳米线在拉伸和压缩单轴应力作用下的能带结构、载流子(电子和空穴)的有效质量以及迁移率的变化.计算结果表明,CdSe纳米线在施加应变或改变横向尺寸时,均表现为直接带隙半导体.随着压缩应变(0;～-10;)和拉伸应变(2;～10;)的增加,CdSe纳米线的带隙逐渐减小,但横向尺寸小的纳米线的带隙相对宽些.导带底电子迁移率随着应变从-10;至10;变化而逐渐减小,而价带顶空穴迁移率在施加应变从4;至10;变化时也缓慢减小.直径为1.2 nm的CdSe纳米线在施加的压缩应变为-10;时,电子和空穴迁移率最大,分别为2890em2·V-1·s-1和2273 cm2·V-·s-1.因此,横向尺寸较小的CdSe纳米线在合适的压应力调控下有望成为一种制备高性能新型纳米电子器件的候选材料.     

氯离子添加剂对钙钛矿太阳能电池性能的调节

过去几年,有机无机杂化的钙钛矿太阳能电池在光伏领域引起了广泛地关注,钙钛矿电池性能提升的关键是制备高质量的钙钛矿薄膜,而引入添加剂是制备高质量钙钛矿薄膜的重要方法之一.本文引入了两种不同的添加剂(浓盐酸和PbCl2)到钙钛矿前驱体溶液中,通过不同摩尔比的掺杂来调控钙钛矿薄膜的结晶度和表面覆盖率.然后采用SEM、XRD和紫外可见吸收光谱等表征手段分析钙钛矿薄膜的性能.结果表明:少量的Cl-添加剂可以优化钙钛矿薄膜的性能,提高钙钛矿层的覆盖率和光吸收特性.当掺杂PbCl2:PbI2摩尔比为1:9时,钙钛矿电池的各项参数有明显的提升,电池的PCE达到了11.35;;作为对比,当掺入HCl:PbI2的摩尔比为1:9时,电池的PCE仅为6.19;.因此PbCl2是比浓盐酸更好的Cl-添加剂,可以改善钙钛矿薄膜质量和提升钙钛矿太阳能电池性能.