Liu Wenbo, Li Mingda, Yang Chao, Wang Nana, Huang Wei, Li Renzhi, Wang Jianpu
Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM) & School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China.
Changzhou University, Changzhou 213164, China.
J Phys Chem Lett. 2023 Sep 7;14(35):7854-7859. doi: 10.1021/acs.jpclett.3c01851. Epub 2023 Aug 25.
Ternary copper halides have become promising materials for UV photodetection due to their stability and eco-friendliness. However, the uncontrollable crystallization induces high-concentration defects in these films, inherently limiting further improvement in device performance. Herein, we reveal the antisolvent-assisted crystallization kinetics mechanism of CsCuI during the film-forming process. The nucleation rate is manipulated by adjusting precursor supersaturation using different antisolvents, resulting in decreased density and preferential orientation of the nuclei within the wet film. Subsequent annealing leads to a homogeneous and low-defect CsCuI film with 40-μm-scale spherulites. A resulting visible-blind ultraviolet photodetector exhibits a responsivity of 8.73 A W, a specific detectivity of 5.28 × 10 jones, and a response speed of 1.12 ms. The unencapsulated photodetector shows negligible degradation of responsivity in ambient air (∼70% humidity) for one month. Moreover, the flexible device with a responsivity of 420.2 mA W and a detectivity of 1.18 × 10 jones also shows excellent bending stability.
三元卤化铜因其稳定性和环境友好性，已成为用于紫外光探测的有前景的材料。然而，不可控的结晶过程会在这些薄膜中诱导产生高浓度缺陷，这从本质上限制了器件性能的进一步提升。在此，我们揭示了在成膜过程中反溶剂辅助的CsCuI结晶动力学机制。通过使用不同的反溶剂调节前驱体过饱和度来控制成核速率，从而降低湿膜中晶核的密度并使其择优取向。随后的退火处理得到了具有40μm尺度球晶的均匀且低缺陷的CsCuI薄膜。由此制备的可见光盲紫外光探测器具有8.73 A/W的响应度、5.28×10琼斯的比探测率以及1.12 ms的响应速度。未封装的光探测器在环境空气（湿度约70%）中放置一个月，其响应度的降解可忽略不计。此外，响应度为420.2 mA/W、比探测率为1.18×10琼斯的柔性器件也表现出优异的弯曲稳定性。
