All‐Inorganic Perovskite Quantum Dot‐Monolayer MoS2 Mixed‐Dimensional van der Waals Heterostructure for Ultrasensitive Photodetector

• Published in: Advanced science 2018-12, Vol.5 (12), p.1801219-n/a
• Main Authors: Wu, Hualin, Si, Haonan, Zhang, Zihan, Kang, Zhuo, Wu, Pingwei, Zhou, Lixin, Zhang, Suicai, Zhang, Zheng, Liao, Qingliang, Zhang, Yue
• Format: Article
• Language: English
• Subjects: mixed‐dimensional van der Waals heterostructures; MoS2; perovskite quantum dots; photodetectors; photogating effect
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.201801219

2D transition metal dichalcogenide (2D‐TMD) materials and their van der Waals heterostructures (vdWHs) have inspired worldwide efforts in the fields of electronics and optoelectronics. However, photodetectors based on 2D/2D vdWHs suffer from performance limitations due to the weak optical absorption of their atomically thin nature. In this work, taking advantage of an excellent light absorption coefficient, low‐temperature solution‐processability, and long charge carrier diffusion length, all‐inorganic halides perovskite CsPbI3−xBrx quantum dots are integrated with monolayer MoS2 for high‐performance and low‐cost photodetectors. A favorable energy band alignment facilitating interfacial photocarrier separation and efficient carrier injection into the MoS2 layer inside the 0D–2D mixed‐dimensional vdWHs are confirmed by a series of optical characterizations. Owing to the synergistic effect of the photogating mechanism and the modulation of Schottky barriers, the corresponding phototransistor exhibits a high photoresponsivity of 7.7 × 104 A W−1, a specific detectivity of ≈5.6 × 1011 Jones, and an external quantum efficiency exceeding 107%. The demonstration of such 0D–2D mixed‐dimensional heterostructures proposed here would open up a wide realm of opportunities for designing low‐cost, flexible transparent, and high‐performance optoelectronics. All‐inorganic perovskite quantum dots are integrated with monolayer MoS2 for a high‐performance and low‐cost photodetector. Owing to the synergistic effect of the photogating mechanism and Schottky barriers modulation, this type‐II band alignment 0D–2D mixed‐dimensional van der Waals heterostructured phototransistor exhibits a high photoresponsivity of 7.7 × 104 A W−1, a specific detectivity of ≈5.6 × 1011 Jones, and an external quantum efficiency exceeding 107%.