High-Performance All-Inorganic CsPbCl₃ Perovskite Nanocrystal Photodetectors with Superior Stability

Abstract

All-inorganic perovskites nanostructures, such as CsPbCl 3 nanocrystals (NCs), are promising in many applications including light-emitting diodes, photovoltaics, and photodetectors. Despite the impressive performance that was demonstrated, a critical issue remains due to the instability of the perovskites in ambient. Herein, we report a method of passivating crystalline CsPbCl 3 NC surfaces with 3-mercaptopropionic acid (MPA), and superior ambient stability is achieved. The printing of these colloidal NCs on the channel of graphene field-effect transistors (GFETs) on solid Si/SiO 2 and flexible polyethylene terephthalate substrates was carried out to obtain CsPbCl 3 NCs/GFET heterojunction photodetectors for flexible and visible-blind ultraviolet detection at wavelength below 400 nm. Besides ambient stability, the additional benefits of passivating surface charge trapping by the defects on CsPbCl 3 NCs and facilitating highefficiency charge transfer between the CsPbCl 3 NCs and graphene were provided by MPA. Extraordinary optoelectronic performance was obtained on the CsPbCl 3 NCs/graphene devices including a high ultraviolet responsivity exceeding 10 6 A/W, a high detectivity of 2 × 10 13 Jones, a fast photoresponse time of 0.3 s, and ambient stability with less than 10% degradation of photoresponse after 2400 h. This result demonstrates the crucial importance of the perovskite NC surface passivation not only to the performance but also to the stability of the perovskite optoelectronic devices.

Recent Progress of Heterojunction Ultraviolet Photodetectors: Materials, Integrations, and Applications

“…The hybrid vdWs heterostructures combine UV photosensitivity and high carrier mobility, and a promoted UV detection (usually broadband spectral response) is achieved. For example, ZnO QDs are printed on graphene and generated a 2D‐0D hybrid vdWs heterostructure with ultrasensitive detection of UV light,146 and other nanocrystals like FeS 2 ‐PbS149 and FeS 2 150 are utilized to similarly strengthen the light absorption in other reports. Apart from the 2D‐0D hybrid vdWs structures, 2D‐0D hybrid structures based on bulk semiconductor crystals are also reported.…”

Recent developments in flexible photodetectors based on metal halide perovskite

“…Moreover, surface‐engineering strategy can be used to resolve instability of the perovskites in ambient. For example, Wu et al used thiol (3‐mercaptopropionic acid, MPA) to passivate inorganic perovskite CsPbCl 3 NCs and the fabricated devices exhibited superior ambient stability . However, hot injection technique requires inert gas protection at a high temperature which can cause high energy consumption.…”

Automated microfluidic screening of ligand interactions during the synthesis of cesium lead bromide nanocrystals

“…5,10,14 The propensity of organic-inorganic hybrid LHPs to degrade over time has shifted interest to more stable all-inorganic analogues, in particular CsPbX 3 (X = halide). [15][16][17] With a view to further improving stability, a major focus has fallen on understanding nanocrystal surface chemistry, 12,15,18 since structural and optical instabilities during isolation, purification and handling are still major issues. 10 Such instability is seen in both the colloidal state and after casting into solid-state devices, where exposure to heat, light, moisture and oxygen severely accelerates physical and optical degradation.…”