溴掺杂CH_3NH_3PbI_3薄膜及其钙钛矿太阳能电池性能研究

Study on the Properties of Bromine Doped CH_3NH_3PbI_3 Films and Their Perovskite Solar Cells

有机-无机铅基卤化物钙钛矿杂合物CH_3NH_3PbI_3作为光吸收材料被广泛应用于太阳能电池中,取得了较高的光电转换效率。基于此,在CH_3NH_3PbI_3基础上对I位进行Br掺杂,采用一步溶液法制备了一系列CH_3NH_3Pb(I_(1-x)Br_x)_3薄膜,研究了溴掺杂对CH_3NH_3PbI_3薄膜物相结构、微观形貌、吸光性能及光电转换性能的影响。结果表明,随着Br掺杂量x由0增加到1,常温下其物相结构逐渐由四方相转变为立方相,并且薄膜在TiO_2纳米柱衬底上的覆盖率逐渐提高,其在可见光及近红外区域内的吸光范围逐渐变窄,其光学带隙由1.59 eV逐渐过渡到2.23 eV。以CH_3NH_3Pb(I_(1-x)Br_x)_3薄膜制备成FTO/BL(blocking layer)-TiO_2/NR(nanorods)-TiO_2/CH_3NH_3Pb(I_(1-x)Br_x)_3/sprio-OMe TAD/Au结构的钙钛矿太阳能电池,发现随着Br掺杂量的增加,太阳能电池的短路电流减小,开路电压增大,填充因子增大,光电转换效率减小。

Organic-inorganic lead based halide perovskite CH_3NH_3PbI_3,which is widely used as a light absorbing material in solar cells,has achieved high photoelectric conversion efficiency in recent years.In this paper,a series of CH_3NH_3Pb（I_（1-x）Br_x）_3films were prepared by the one-step solution method. The effects of bromine concentration on their crystalline structure,morphology,absorption properties and photo electric conversion properties were studied.It was found that with the increasing amount of Br,the crystalline structure gradually changed from tetragonal to cubic,in company with the continuous enhancement of the film coverage on the TiO_2 nanorods substrate. As x increased from 0 to 1,their optical band gap increased gradually from 1.59 eV to 2.23 eV. The CH_3NH_3Pb（I_（1-x）Br_x）_3films were further used to fabricate perovskite solar cells with the device structure of FTO / BL（ blocking layer）-TiO_2/ NR（ nanorods）-TiO_2/ CH_3NH_3Pb（I_（1-x）Br_x）_3/ sprio-OMe TAD / Au. The experimental results show that with the increase of Br doping amount,the short circuit current and the photoelectric conversion efficiency of solar cells decreased,while the open circuit voltage and the fill-factor increased gradually.