A perovskite single crystal with one-dimensional structure enables photodetection with negligible hysteresis

The robust material tunability of the hybrid organic-inorganic perovskite (HOIP) has attracted considerable research interests to explore the application in photoelectronic devices. Huge hysteresis has been recognised as a main problem in HOIP-based photoelectric devices; the origin of hysteresis has been attributed to the ion migration and trap states in HOIP materials. In this study, we designed and synthesised a HOIP single crystal with one-dimensional structure where the PbI42- octahedron is caged by the organic chains. The ion migration can be dramatically suppressed by the quantum size effect. Besides, in the single crystal trap states density is ultra-low due to the absence of grain boundaries. As a result, photodetectors based on this 1D HOIP single crystal show negligible hysteresis I-V curves. Moreover, a high quality ohmic contact is formed between electrodes and 1D HOIP, which is beneficial for photocarrier extraction. A responsivity of 80 mA W-1 and EQE of 30% are realised. The response speed is determined to be less than 0.4 ms. In addition, the photodetectors based on the novel 1D single crystal present good stability; after 3 months of ambient storage, 85% of its original photocurrent generation ability is retained.

Automated summary

A HOIP single crystal with one-dimensional structure was successfully designed and synthesized in this study, showing suppressed ion migration and ultra-low trap states density. The photodetector based on this 1D single crystal exhibited excellent performance with negligible hysteresis, high responsivity and EQE. Additionally, the device showed good stability after 3 months of ambient storage.