Methyl-substituted germanane is an emerging material that has been proposed for novel applications in optoelectronics, photoelectrocatalysis, and biosensors. It is a two-dimensional semiconductor with a strong above-gap fluorescence associated with water intercalation. Here, we use time-resolved photoluminescence spectroscopy to understand the mechanism causing this fluorescence. We show that it originates from two distinct exciton populations. Both populations recombine exponentially, accompanied by the thermally activated transfer of exciton population from the shorter- to the longer-lived type. The two exciton populations involve different electronic levels and couple to different phonons. The longer-lived type of exciton migrates within the disordered energy landscape of localized recombination centers. These outcomes shed light on the fundamental optical and electronic properties of functionalized germanane, enabling the groundwork for future applications in optoelectronics, light harvesting, and sensing.
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http://dx.doi.org/10.1021/acs.nanolett.1c04357 | DOI Listing |
Chem Sci
January 2025
Department of Chemistry, The University of Adelaide Adelaide South Australia 5005 Australia
Singlet fission (SF) is a process that is potentially beneficial for photovoltaics by producing two triplet excitons from a single photon, but its application is often hindered by the inability to effectively separate the resultant triplet excitons. It has been proposed that an energy gradient can assist in separating triplet excitons through triplet energy transfer between chromophores of different triplet energies, but this approach has only been studied in solution and the efficacy of this strategy in the solid state is under explored. Here, we investigate energy-gradient-driven SF in a disordered solid state, in the form of suspensions of 5,12-bis(triisopropylsilylethnyl)tetracene:6,13-bis(triisopropylsilylethnyl)pentance (TIPS-Tn:TIPS-Pn) blend nanoparticles (NPs).
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory of Superhard Materials, Synergetic Extreme Condition High-Pressure Science Center, College of Physics, Jilin University, Changchun, China.
Metal-organic frameworks that feature hybrid fluorescence and phosphorescence offer unique advantages in white-emitting communities based on their multiple emission centers and high exciton utilization. However, it poses a substantial challenge to realize superior white-light emission in single-component metal-organic frameworks without encapsulating varying chromophores or integrating multiple phosphor subunits. Here, we achieve a high-performance white-light emission with photoluminescence quantum yield of 81.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Physics and Chemistry, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea.
Magnetotransport of conventional semiconductor based double layer systems with barrier suppressed interlayer tunneling has been a rewarding subject due to the emergence of an interlayer coherent state that behaves as an excitonic superfluid. Large angle twisted bilayer graphene offers unprecedented strong interlayer Coulomb interaction, since both layer thickness and layer spacing are of atomic scale and a barrier is no more needed as the twist induced momentum mismatch suppresses tunneling. The extra valley degree of freedom also adds richness.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, P.R. China.
The evolution of photosynthetic reaction centers (RCs) from anoxygenic bacteria to higher-order oxygenic cynobacteria and plants highlights a remarkable journey of structural and functional diversification as an adaptation to environmental conditions. The role of chirality in these centers is important, influencing the arrangement and function of key molecules involved in photosynthesis. Investigating the role of chirality may provide a deeper understanding of photosynthesis and the evolutionary history of life on Earth.
View Article and Find Full Text PDFRecently, biomass-derived carbon dots (CDs) have attracted considerable attention in high-technology fields due to their prominent merits, including brilliant luminescence, superior biocompatibility, and low toxicity. However, most of the biomass-derived CDs only show bright fluorescence in diluted solution because of aggregation-induced quenching effect, hence cannot exhibit solid-state long-lived room-temperature phosphorescence (RTP) in ambient conditions. Herein, matrix-free solid-state RTP with an average lifetime of 0.
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