Identification and Suppression of Point Defects in Bromide Perovskite Single Crystals Enabling Gamma-Ray Spectroscopy
Journal article, 2024

Methylammonium lead tribromide (MAPbBr3) stands out as the most easily grown wide-band-gap metal halide perovskite. It is a promising semiconductor for room-temperature gamma-ray (γ-ray) spectroscopic detectors, but no operational devices are realized. This can be largely attributed to a lack of understanding of point defects and their influence on detector performance. Here, through a combination of crystal growth design and defect characterization, including positron annihilation and impedance spectroscopy, the presence of specific point defects are identified and correlated to detector performance. Methylammonium (MA) vacancies, MA interstitials, and Pb vacancies are identified as the dominant charge-trapping defects in MAPbBr3 crystals, while Br vacancies caused doping. The addition of excess MABr reduces the MA and Br defects and so enables the detection of energy-resolved γ-ray spectra using a MAPbBr3 single-crystal device. Interestingly, the addition of formamidinium (FA) cations, which converted to methylformamidinium (MFA) cations by reaction with MA+ during crystal growth further reduced MA defects. This enabled an energy resolution of 3.9% for the 662 keV 137Cs line using a low bias of 100 V. The work provides direction toward enabling further improvements in wide-bandgap perovskite-based device performance by reducing detrimental defects.

defects

gamma-ray detector

perovskite single crystal

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Published in

Advanced Materials

09359648 (ISSN) 15214095 (eISSN)

Vol. 36 Issue 35 art. no 2406193

Research Project(s)

Atomistic Design of Photoabsorbing Materials

Swedish Research Council (VR) (2019-03993), 2020-01-01 -- 2023-12-31.

Ab Initio Description of Complete Semiconductor Devices

Swedish Foundation for Strategic Research (SSF) (FFL21-0129), 2022-08-01 -- 2027-12-31.

Categorizing

Subject Categories (SSIF 2011)

Materials Chemistry

Condensed Matter Physics

Identifiers

DOI

10.1002/adma.202406193

PubMed

39003617

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Latest update

9/7/2024 4