Fabrication of (101)-oriented CsPbBr₃ thick films with high carrier mobility using a mist deposition method

Abstract

CsPbBr3 is a promising candidate for highly sensitive flat-panel X-ray detectors due to its excellent optoelectronic properties. Thus, a method of preparing thick CsPbBr3 films (> 10 µm) over large areas (> 10 × 10 cm 2) is required. Herein, we report the fabrication of thick CsPbBr3 films using a scalable mist deposition method. In this method, the film thickness was controlled and up-scaled by the number of deposition cycles. The obtained CsPbBr3 films were composed of highly (101)-oriented columnar crystals and had a high carrier mobility of 13 cm 2 V −1 s −1 , which is comparable to that for single crystals. A highly sensitive flat-panel X-ray detector (FPD), which enables medical X-ray imaging at low dose, is required to reduce the risk of cancer 1). Amorphous selenium (a-Se) is commonly used for the photoconductive layer because it can be prepared through simple methods such as thermal evaporation. However, the sensitivity of FPD using a-Se is limited due to its low

Halide perovskites: A dark horse for direct X‐ray imaging

“…Moreover, it was found that the cooling rate profoundly affect the quality of the as-grown CsPbBr 3 . With a slow cooling rate, the quasimonocrystalline CsPbBr 3 obtained showed rather uniform morphology and a preferred crystal orientation along (101). As a result, it exhibited a high μτ product of 1.3 × 10 −2 cm 2 V −1 , which approached the record value of single-crystalline perovskites reported so far.…”

“…A, A photograph of Cs‐MA‐FA perovskite based flexible X‐ray detector; A photograph and the corresponding X‐ray image of an investigated object; Reproduced with permission form Reference 99, Copyright 2020, American Chemical Society 99 ; B, Schematic illustration of the dissolution‐recrystallization approach; Reproduced with permission form Reference 100, Copyright 2019, Wiley‐VCH 100 ; C, Schematic illustration of a ultrasonic‐assisted mist deposition protocol; Reproduced with permission form Reference 101, Copyright 2019, The Japan Society of Applied Physics 101 ; D, Photographs and, E, the cross‐sectional SEM images of CsPbBr 3 grown on ITO and ITO/Polymer; Reproduced with permission form Reference 102, Copyright 2020, Materials Research Society 102 ; F, Schematic diagram of the hot‐pressing protocol; G, A cross‐sectional SEM image of the thick CsPbBr 3 film; H, X‐ray response of the CsPbBr 3 detector with different dose rates at 4.2 V mm −1 ; I, The sensitivity and photoconductive gain and, J, the LoD of the CsPbBr 3 detector as a function of applied bias; Reproduced with permission form Reference 44, Copyright 2019, Wiley‐VCH 44 …”

Ligand-Length Modification in CsPbBr3 Perovskite Nanocrystals and Bilayers with PbS Quantum Dots for Improved Photodetection Performance

“…This nonlinear behavior originates from the space-charge-limited current (SCLC) effect that occurs when uncompensated charge carriers are injected into the material from the MSM contacts. In this condition, the mobility (μ) can be approximately estimated in the SCLC region (J ~ V 2 ) under dark conditions by using the Mott–Gurney law [ 52 ]: where is the channel length (20 μm), ε 0 is the permittivity of vacuum, and ε is the relative dielectric constant of CsPbBr 3 , which is in the order of ~24 [ 53 ].…”

Fabrication of CsPbBr3 Thick Films by Using a Mist Deposition Method for Highly Sensitive X-ray Detection

“…The carrier and dilution gas flow rate were set at 0.375 and 4.625 L min -1 , respectively. The substrate temperature was set at 150 °C optimized for the fabrication of highly (101)-oriented CsPbBr3 films in our previous report [21]. In this study, CsPbBr3 was deposited onto a reduced area of 26 × 10 mm 2 by moving the substrate by 10 mm at a speed of 0.80 mm s -1 .…”

“…Recently, we reported the fabrication of (101)-oriented CsPbBr3 films with a thickness of up to 28 μm using a mist deposition method, which is suitable for the large area production [21]. Much thicker films (over 100 μm) are preferable to a highly sensitive X-ray detection.…”