The hot-phonon bottleneck effect in lead-halide perovskites (APbX) prolongs the cooling period of hot charge carriers, an effect that could be used in the next-generation photovoltaics devices. Using ultrafast optical characterization and first-principle calculations, four kinds of lead-halide perovskites (A=FA/MA/Cs, X=I/Br) are compared in this study to reveal the carrier-phonon dynamics within. Here we show a stronger phonon bottleneck effect in hybrid perovskites than in their inorganic counterparts. Compared with the caesium-based system, a 10 times slower carrier-phonon relaxation rate is observed in FAPbI. The up-conversion of low-energy phonons is proposed to be responsible for the bottleneck effect. The presence of organic cations introduces overlapping phonon branches and facilitates the up-transition of low-energy modes. The blocking of phonon propagation associated with an ultralow thermal conductivity of the material also increases the overall up-conversion efficiency. This result also suggests a new and general method for achieving long-lived hot carriers in materials.
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http://dx.doi.org/10.1038/ncomms14120 | DOI Listing |
Inorg Chem
January 2025
College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, PR China.
Lead halide perovskites have garnered interest in light-emitting diode (LED) applications due to their strong emission and tunable properties. However, conventional synthesis methods involve energy-intensive thermal processes and hazardous organic solvents, raising environmental concerns. In this study, we report a simple and eco-friendly mechanochemical approach that produces phase-pure blue-emitting CsCuI (emission at 440 nm) and yellow-emitting CsCuI (emission at 570 nm) phosphors through polarity modulation and control of grinding duration.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
Photodetectors based on lead halide perovskites often show excellent performance but poor stability. Herein, we demonstrate a photodetector based on MAPbBr single crystals passivated with an ultrathin layer of PbSO, which shows superior detectivity and on/off ratios compared to the control device due to the combined effect of lower surface traps, reduced recombination and low dark current. In addition, the device retained ∼56% of its initial * with an impressive on/off ratio of ∼801 after one year compared to ∼22% of * and an on/off ratio of ∼6 of the control device.
View Article and Find Full Text PDFACS Nano
January 2025
College of Materials and Chemistry & Chemical Engineering, Nuclear Technology Key Laboratory of Earth Science, Chengdu University of Technology, Chengdu 610059, China.
The precise patterning of elastic semiconductors holds encouraging prospects for unlocking functionalities and broadening the scope of optoelectronic applications. Here, perovskite films with notable elasticity capable of stretching over 250% are successfully fabricated by using a continuous-wave (CW) laser-patterning technique. Under CW laser irradiation, perovskite nanoparticles (NPs) undergo meticulous crystallization within the thermoplastic polyurethane (TPU) matrix, which yields the capability of an unparalleled stretch behavior.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, 710119, P. R. China.
Understanding the oxygen evolution reaction (OER) mechanism is pivotal for improving the overall efficiency of water electrolysis. Despite methylammonium lead halide perovskites (MAPbX) have shown promising OER performance due to their soft-lattice nature that allows lattice-oxygen oxidation of active α-PbO layer surface, the role of A-site MA or X-site elements in the electrochemical reconstruction and OER mechanisms has yet to be explored. Here, it is demonstrated that the OER mechanism of perovskite@zeolite composites is intrinsically dominated by the A-site group of lead-halide perovskites, while the type of X-site halogen is crucial for the reconstruction kinetics of the composites.
View Article and Find Full Text PDFNanoscale
January 2025
Polymers and Functional Materials Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad, 500007, India.
Utilizing the soft-lattice nature of metal halide perovskites, we employ post-synthetic cross-ion exchange to synthesize a series of narrow band-gap colloidal nanocrystals of methylammonium-based lead iodide solid solutions of composition FAMAPbI, as well as those of triple-cation composition CsFAMAPbI (TCPbI). The ability to finely tune the compositions not only helps in tailoring the optical properties in the near-infrared region, but also improves the stability of these colloidal nanocrystals towards moisture, which has been demonstrated as compared to their bulk counterparts. The thermal stability of these solid solutions is also comparable to that of the bulk, as evidenced by thermogravimetric studies.
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