Properties and solar cell applications of Pb-free perovskite films formed by vapor deposition
Properties and solar cell applications of Pb-free perovskite films formed by vapor deposition
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DOI：
10.1039/c5ra21291j
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发表时间：
2016-01-01
期刊：
影响因子：
3.9
通讯作者：
Qi, Yabing
中科院分区：
文献类型：
--
作者：
Jung, Min-Cherl;Raga, Sonia R.;Qi, Yabing
我们使用两种基于气相沉积的方法（即，共蒸发和顺序蒸发）。我们获得了关于这些无铅钙钛矿薄膜的结构和电子性质的全面信息。X射线衍射结果证实了MASnBr（3）的晶体结构。使用UV-Vis测量，我们确定这些膜的光学带隙类似于2.2 eV。的紫外光电子能谱的结果的基础上，功函数和电离能测定为4.3和6.1 eV，分别。采用平面结构的这种钙钛矿膜的太阳能电池用各种空穴传输层（HTL）（螺-OMeCl、C60和P3 HT）制造。对于通过共沉积制备的钙钛矿薄膜，我们得到的太阳能电池效率范围从0.03%到0.35%。另一方面，当我们使用顺序沉积时，使用P3 HT作为HTL获得了高达1.12%的更高效率。我们证实，基于MASnBr 3的钙钛矿太阳能电池的低效率是由于其相对高的电阻和在制造期间通过空气暴露在顶表面上快速形成Sn-Br氧化物。顺序沉积方法有助于避免这种氧化，从而导致更高的效率。
We deposited lead-free CH3NH3SnBr3 - organometal halide perovskite films using two vapor deposition-based methods (i.e., co-evaporation and sequential evaporation) using SnBr2 and CH3NH3Br. We obtained comprehensive information about the structural and electronic properties of these Pb-free perovskite films. X-ray diffraction results confirmed the crystalline structure of MASnBr(3). Using UV-Vis measurements, we determined the optical bandgap of these films to be similar to 2.2 eV. On the basis of ultraviolet photoemission spectroscopy results, the work function and ionization energy were measured to be 4.3 and 6.1 eV, respectively. Solar cells employing such a perovskite film in a planar structure were fabricated with various hole transport layers (HTLs) (spiro-OMeTAD, C60, and P3HT). For perovskite films prepared by co-deposition, we obtained solar cell efficiencies ranging from 0.03 to 0.35%. On the other hand, when we used sequential deposition, a higher efficiency up to 1.12% was obtained using P3HT as the HTL. We confirmed that the low efficiency of MASnBr3 based perovskite solar cells is due to their relatively high resistance and the fast formation of Sn-Br oxide on the top surface by air exposure during fabrication. The sequential deposition method helped avoid such oxidation resulting in higher efficiencies.