Photocarrier Recombination and Injection Dynamics in Long-Term Stable Lead-Free CH3NH3SnI3 Perovskite Thin Films and Solar Cells
Photocarrier Recombination and Injection Dynamics in Long-Term Stable Lead-Free CH3NH3SnI3 Perovskite Thin Films and Solar Cells
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DOI：
10.1021/acs.jpcc.7b06199
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发表时间：
2017-08-03
影响因子：
3.7
通讯作者：
Kanemitsu, Yoshihiko
中科院分区：
文献类型：
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作者：
Handa, Taketo;Yamada, Takumi;Kanemitsu, Yoshihiko
我们研究了封装的长期稳定的CH 3 NH3 SnI 3（MASnI（3））薄膜和太阳能电池器件的近带边光学响应和光生载流子动力学。用SnF 2制备的MASnI（3）薄膜显示出1.25 eV的带隙，而不含SnF 2的薄膜具有显著的吸收边蓝移。相反，PL峰能量不受SnF 2的添加的影响。这些观察结果表明，在无SnF 2的MASnI（3）样品中吸收边的蓝移是由于显著的无意空穴掺杂引起的Burstein-Moss位移。此外，时间分辨的光致发光测量显示，通过添加SnF 2的薄膜的光载流子寿命增加了一个数量级，这使得能够改善太阳能电池的器件性能。我们澄清了在MASnI 3太阳能电池中，由于钙钛矿层中的大的非辐射复合率，短路电流保持在明显低于理想值，导致进入电荷传输层的小的光载流子注入效率。
We investigated the near-band-edge optical responses and photocarrier dynamics of encapsulated long-term stable CH3NH3SnI3 (MASnI(3)) thin films and solar-cell devices. The MASnI(3) thin film prepared with SnF2 exhibited a bandgap of 1.25 eV, while the film without SnF2 had a significantly blueshifted absorption edge. On the contrary, the PL peak energies were not influenced by the addition of SnF2. These observations indicate that the blueshift of the absorption edge in the SnF2-free MASnI(3) sample is due to the Burstein-Moss shift induced by a significant unintentional hole doping. Furthermore, time resolved photoluminescence measurements revealed that by adding SnF2 the photocarrier lifetime of the film increased by one order of magnitude, which enables improved device performance of solar cells. We clarified that in the MASnI3 solar cells the short-circuit current stays significantly below the ideal value due to a large nonradiative recombination rate in the perovskite layer, resulting in a small photocarrier-injection efficiency into the charge-transport layers.