Highly Oriented Thin Films of 2D Ruddlesden‐Popper Hybrid Perovskite toward Superfast Response Photodetectors

Abstract

2D hybrid perovskites have shown great promise in the photodetection field, due to their intriguing attributes stemming from unique structural architectures. However, the great majority of detectors based on this 2D system possess a relatively low response speed (≈ms), making it extremely urgent to develop new candidates for superfast photodetection. Here, a new organic–inorganic hybrid perovskite, (PA)2(FA)Pb2I7 (EFA, where PA is n‐pentylaminium and FA is formamidine), which features the 2D Ruddlesden–Popper type perovskite framework that is composed of the corner‐sharing PbI6 octahedra is reported. Significantly, photodetectors fabricated on highly oriented thin films, which exhibit a perfect orientation parallel to 2D inorganic perovskite layers, exhibit a superfast response time up to ≈2.54 ns. To the best of the knowledge, this figure‐of‐merit catches up with that of the top‐ranking commercial materials, and sets a new record for 2D hybrid perovskite photodetectors. Moreover, extremely high photodetectivity (≈1.73 × 1014 Jones, under an incident power intensity of ≈46 µW cm−2), considerable switching ratios (>103), and low dark current (≈10 pA) are also achieved in the detector, indicating its great potential for high‐efficiency photodetection. These results shed light on the possibilities to explore new 2D candidates for assembling future high‐performance optoelectronic devices.

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

“…The short conduction pathway for photogenerated charge carriers ensures the related photoelectric devices with fast response speed. Moreover, very low concentration of defects and traps in perovskites greatly reduces charge carrier recombination 58. These characteristics strongly recommend the organic–inorganic hybrid perovskites as ideal building blocks for high‐performance PDs.…”

Layered metal halide perovskite solar cells: A review from structure‐properties perspective towards maximization of their performance and stability

“…The most interesting strategy to increase the charge mobility on layered perovskites, however, is to organize the inorganic slabs perpendicularly to the substrate. This orientation takes direct advantage of the anisotropic charge transport of these materials, allowing charge carriers to move easily in the direction of the transport layers of the device (Figure 6B right) 13,28,60,77,135 . The growth mechanism is still not fully clarified, but studies indicate that the vertical growth of the layers happens when the crystallization occurs slowly and starts at the air‐liquid interface between the precursor solution and the substrate 133,134 .…”

Strongly Luminescent Dion–Jacobson Tin Bromide Perovskite Microcrystals Induced by Molecular Proton Donors Chloroform and Dichloromethane

“…Metal halide perovskites with a general formulae ABX 3 , where A = CH 3 NH 3 + (methylammonium), HC(NH 2 ) 2 + (formamidinium), Cs + ; B = Pb 2+ , Ge 2+ , Sn 2+ ; and X = I − , Br − , Cl − have been recently considered for a variety of applications, including photovoltaics, [ 1 ] light‐emitting diodes (LEDs), [ 2 ] lasers, [ 3 ] photodetectors, [ 4 ] and memory (data storage) media. [ 5 ] However, their intrinsic ionic nature causes inferior stability against polar solvents, UV light, and electric fields, which greatly restricts their practical use.…”