The band gap energy of halide perovskite semiconductors is manipulated by controlling the halide composition, and mixed halide perovskites are receiving much attention as top cell materials for tandem solar cells. To understand dynamic aspects of photoinduced halide segregation in mixed-halide perovskite films, we use a hyperspectral imaging technique. We reveal the space- and time-resolved photoluminescence (PL) spectra of CsFAPbIBr perovskite films during prolonged light illumination. Under applied electric fields, we observe photoinduced phase segregation at the excitation laser spot, with a line-shape I-rich region of low PL efficiency appearing near the anode electrode. This I-rich region moves from the anode to the cathode electrodes and stops at the laser excitation spot. We discuss the significant enhancement of halide ion migration under light illumination and the dynamical changes of photoinduced halide segregation.
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http://dx.doi.org/10.1021/acs.jpclett.4c03077 | DOI Listing |
Nat Commun
January 2025
State Key Laboratory of Petroleum Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China.
Intensified host-guest electronic interplay within stable metal-organic cages (MOCs) presents great opportunities for applications in stimuli response and photocatalysis. Zr-MOCs represent a type of robust discrete hosts for such a design, but their host-guest chemistry in solution is hampered by the limited solubility. Here, by using pyridinium-derived cationic ligands with tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (BAr) as solubilizing counteranions, we report the preparation of soluble Zr-MOCs of different shapes (1-4) that are otherwise inaccessible through a conventional method.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia.
The development of efficient artificial photosynthesis systems is crucial for sustainable chemical production, as they mimic natural processes to convert solar energy into chemical products, thereby addressing both energy and environmental challenges. The main bottlenecks in current research include fabricating highly selective, stable, and scalable catalysts, as well as effectively harnessing the full spectrum of light, particularly the low-energy, long-wavelength portion. Herein, we report a novel composite photocatalyst system based on lead halide perovskites embedded in functionalized MOF glass.
View Article and Find Full Text PDFACS Nano
December 2024
School of Physical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
2D Ruddlesden-Popper (RP) perovskites, upon inclusion of a chiral amine, exhibit chirality-induced spin selectivity (CISS). Although alloying at the halogen site in MBA-based RPs (MBA: methylbenzylammonium) is one of the suitable routes to tune the CISS effect, the mixed-halide RP perovskites exhibited complete suppression of chirality when probed through circular dichroism (CD). Here, we present the CISS effect in a series of mixed-halide RP perovskites.
View Article and Find Full Text PDFOrg Lett
January 2025
Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Herein, we develop a dual catalytic platform for the 1,2- or 1,4-alkylacylation reaction of 1,3-dienes with readily available alkyl halides and aldehydes by merging -heterocyclic carbene catalysis with photoinduced palladium catalysis. A series of β,γ-unsaturated ketones are obtained in good to high yields. Mechanistic studies suggest that this reaction involves a radical process.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India.
An established concept to create radical intermediates is photoexcitation of a catalyst to a higher energy intermediate, subsequently leading to a photoinduced electron transfer (PET) with a reaction partner. The known concept of consecutive photoinduced electron transfer (con-PET) leads to catalytically active species even higher in energy by the uptake of two photons. Generally speaking, increased photon uptake leads to a more potent reductant.
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