School of Materials Science and Enigneering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
Nano Lett. 2018 Feb 14;18(2):1213-1220. doi: 10.1021/acs.nanolett.7b04809. Epub 2018 Feb 5.
High-quality organic-inorganic hybrid perovskite films are crucial for excellent performance of photoelectric devices. Herein, we demonstrate a pressure-assisted space-confined solvent-engineering strategy to grow highly oriented, pinhole-free thin films of CHNHPbI with large-scale crystalline grains, high smoothness, and crystalline fusion on grain boundaries. These single-crystalline grains vertically span the entire film thickness. Such a film feature dramatically reduces recombination loss and then improves the transport property of charge carriers in the films. Consequently, the photodetector devices, based on the high-quality CHNHPbI films, exhibit high photocurrent (105 μA under 671 nm laser with a power density of 20.6 mW/cm at 10 V), good stability, and, especially, an ultrahigh on/off ratio (I/I > 2.2 × 10 under an incident light of 20.6 mW/cm). These excellent performances indicate that the high-quality films will be potential candidates in other CHNHPbI-based photoelectric devices.
高质量的有机-无机杂化钙钛矿薄膜对于光电设备的优异性能至关重要。在此，我们展示了一种压力辅助的空间受限溶剂工程策略，用于生长具有大晶粒尺寸、高平整度和晶界融合的高度取向、无针孔的 CHNHPbI 薄膜。这些单晶颗粒垂直贯穿整个薄膜厚度。这种薄膜结构显著降低了复合损失，从而提高了薄膜中电荷载流子的输运性能。因此，基于高质量 CHNHPbI 薄膜的光电探测器器件表现出高的光电流（在 671nm 激光下功率密度为 20.6mW/cm2 时为 105μA，在 10V 下）、良好的稳定性，特别是超高的开关比（在 20.6mW/cm2 的入射光下 I/I > 2.2×10）。这些优异的性能表明，高质量的薄膜将是其他基于 CHNHPbI 的光电设备的潜在候选材料。
