The optoelectronic properties of lead halide perovskite thin films can be tuned through compositional variations and strain, but the associated nanocrystalline structure makes it difficult to untangle the link between composition, processing conditions, and ultimately material properties and degradation. Here, we study the effect of processing conditions and degradation on the local photoconductivity dynamics in [(CsPbI)(FAPbI)(MAPbBr)] and (FACsPbI) perovskite thin films using temporally and spectrally resolved microwave near-field microscopy with a temporal resolution as high as 5 ns and a spatial resolution better than 50 nm. For the latter FACs formulation, we find a clear effect of the process annealing temperature on film morphology, stability, and spatial photoconductivity distribution. After exposure of samples to ambient conditions and illumination, we find spectral evidence of halide segregation-induced degradation below the instrument resolution limit for the mixed halide formulation, while we find a clear spatially inhomogeneous increase in the carrier lifetime for the FACs formulation annealed at 180 °C.
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http://dx.doi.org/10.1021/acs.jpclett.2c00233 | DOI Listing |
J Am Chem Soc
December 2024
Key Laboratory of Photoelectric Conversion and Utilization of Solar Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.
In recent years, perovskite solar cells (PSCs) have garnered considerable attention as a prime candidate for next-generation photovoltaic technology. Ensuring the structural stability of perovskites is crucial to the operational reliability of these devices. However, the nonphotoactive yellow phase (δ-FAPbI) of formamidine (FA)-based perovskites is more favorable in thermodynamics, making it challenging to achieve pure α phase in crystallization.
View Article and Find Full Text PDFSmall Methods
December 2024
Department of Advanced Materials for Energy Applications, Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià del Besòs, Barcelona, 08930, Spain.
Functional properties of mixed ionic electronic conductors (MIECs) can be radically modified by (de)insertion of mobile charged defects. A complete control of this dynamic behavior has multiple applications in a myriad of fields including advanced computing, data processing, sensing or energy conversion. However, the effect of different MIEC's state-of-charge is not fully understood yet and there is a lack of strategies for fully controlling the defect content in a material.
View Article and Find Full Text PDFACS Appl Energy Mater
December 2024
Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle-upon-Tyne NE1 8QH, United Kingdom.
The chalcogenide perovskite BaZrS has strong visible light absorption and high chemical stability, is nontoxic, and is made from earth-abundant elements. As such, it is a promising candidate material for application in optoelectronic technologies. However, the synthesis of BaZrS thin-films for characterization and device integration remains a challenge.
View Article and Find Full Text PDFChemistry
December 2024
East China University of Science and Technology, School of Materials Science and Engineering, meilong Road, 200237, shanghai, CHINA.
Perovskite-based photodetectors (PDs) are broadly utilized in optical communication, non-destructive testing, and smart wearable devices due to their ability to convert light into electrical signals. However, toxicity and instability hold back their mass production and commercialization. The lead-free Cs2AgBiBr6 double perovskite film, promised to be an alternative, is fabricated by electrophoretic deposition (EPD), which compromises film quality.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Department of Materials Science and Engineering, Chosun University, Gwangju 61452, Korea.
With the applications of in situ X-ray diffraction (XRD), electrical - measurement, and ambient pressure hard X-ray photoelectron spectroscopy (AP-HAXPES), the characteristics of the topotactic phase transition of LaCoO (LCO) thin films are examined. XRD measurements show clear evidence of structural phase transition (SPT) of the LCO thin films from the perovskite (PV) LaCoO to the brownmillerite (BM) LaCoO phases through the intermediate LaCoO phase at a temperature of 350 °C under high-vacuum conditions, ∼10 mbar. The reverse SPT from BM to PV phases is also found under ambient pressure (>100 mbar) of air near 100 °C.
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