High scintillation yield and fast response to alpha particles from thin perovskite films deposited by pulsed laser deposition

Abstract

Although the field of solar cells is the most popular application of perovskite materials, their use in radiation detection applications is emerging. The success of perovskites as radiation detectors rests partly on the same material properties that have led to successful optoelectronics applications, meaning that other specific properties, like large stopping power, high mobility lifetime product, fast response, and large bulk resistance, play a role. In this respect, inorganic perovskites are attracting a lot of attention as scintillator materials with performances sensitive to material shape (single crystals, nanocrystals, and thin films) and growth methods. In this study, we report on the morphological, structural, and optical response of thin CsPbBr3-based perovskite films, deposited by Pulsed Laser Deposition (PLD) and post-growth annealed at 350°C in air, following excitation by different particle sources. The annealing treatment resulted in a prompt structural refinement, grain growth, and oxygen bonding to the Pb phase together with an enrichment of the surface in chemo-adsorbed oxygen probably due to Cs–O interactions, as evidenced by X-ray photoelectron spectroscopy. The film behavior under 2 MeV H+ ion beam irradiation at different fluences was analyzed together with its scintillation properties following an interaction with α particles from an Am-241 radioactive source demonstrating a very fast response for an inorganic material (∼5ns) and a photoelectron yield of about ∼47% with respect to a commercial CsI:Tl scintillator.

Study of a metal-halide perovskite CsPbBr3 thin film deposited on a 10B layer for neutron detection

“…Only a slight increase of the peak at 310 nm has been observed, which is in agreement with XRD spectra and indicates a slow evolution of the Cs 4 PbBr 6 phase. Details about the optical emission properties of the deposited films are reported in [23,24,45]. Consistent with what was reported in [23], the exposure to the atmosphere has been responsible for film luminescence under optical excitation due to oxygen uptake, which passively forms halide vacancies [54][55][56].…”

“…Similar effects can be obtained by prolonged exposure to the atmosphere [24]. Because of the role of the atmosphere on the emission properties of the film and considering that it has not been possible to thermally treat the film in this case due to the presence of the carbon fiber, the CsPbBr 3 film has been deposited using different growth conditions than those reported in [23]. A detailed discussion and motivation about the choice of the experimental parameters and their role in the film properties can be found in [23,24,45].…”

“…The film morphology and its time evolution have been analyzed by atomic force microscopy (AFM) with a Park XE-70 Instruments microscope (Park Systems, Suwon, Korea), operating in non-contact mode at room temperature and in the air environment. The optical and emission properties of the CsPbBr 3 film have been determined by UV-Vis and photoluminescence (PL) measurements [23]. Absorbance spectra were measured by a PerkinElmer Lambda 900 UV spectrophotometer (PerkinElmer Company, Waltham, MA) over a range of wavelengths of 200-800 nm and with a wavelength resolution of 3 nm.…”

“…Because of the role of the atmosphere on the emission properties of the film and considering that it has not been possible to thermally treat the film in this case due to the presence of the carbon fiber, the CsPbBr 3 film has been deposited using different growth conditions than those reported in [23]. A detailed discussion and motivation about the choice of the experimental parameters and their role in the film properties can be found in [23,24,45]. In particular, the film has been deposited at a low vacuum pressure (10 −2 Pa), higher target-substrate distance (6 cm instead of 4 cm), and a lower repetition rate (2 Hz instead of 5 Hz).…”

“…In previous work performed by our group, the response of thin CsPbBr 3 -based perovskite films, deposited by pulsed laser deposition (PLD), was studied under α particle ( 241 Am source) irradiation. A very fast response (τ ∼ 5 ns) was found, and a photoelectron yield of 40 % with respect to the CsI:Tl scintillator was obtained [23]. Also, it was analyzed the effects of post-growth aging, oxygen absorption, and annealing on the film properties, evaluating various annealing procedures carried out in different atmospheres and at different temperatures, and it was found to have a stable behavior over a long time, even when the films are exposed to high relative humidity conditions [24].…”