Carbon nanotubes are a promising means of capturing photons for use in solar cell devices. We time-resolved the photoexcitation dynamics of coupled, bandgap-selected, semiconducting carbon nanotubes in thin films tailored for photovoltaics. Using transient absorption spectroscopy and anisotropy measurements, we found that the photoexcitation evolves by two mechanisms with a fast and long-range component followed by a slow and short-range component. Within 300 fs of optical excitation, 20% of nanotubes transfer their photoexcitation over 5-10 nm into nearby nanotube fibers. After 3 ps, 70% of the photoexcitation resides on the smallest bandgap nanotubes. After this ultrafast process, the photoexcitation continues to transfer on a ~10 ps time scale but to predominantly aligned tubes. Ultimately the photoexcitation hops twice on average between fibers. These results are important for understanding the flow of energy and charge in coupled nanotube materials and light-harvesting devices.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/nl304591w | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Interatomic Coulombic decay in lithium-doped large helium nanodroplets induced by photoelectron impact excitation.
Rep Prog Phys
January 2025
Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus, Midtjylland, 8000, DENMARK.
Irradiation of condensed matter with ionizing radiation generally causes direct photoionization as well as secondary processes that often dominate the ionization dynamics. Here, large helium (He) nanodroplets with radius ≳ 40 nm doped with lithium (Li) atoms are irradiated with extreme ultraviolet (XUV) photons of energy hν ≥ 44.4 eV and indirect ionization of the Li dopants is observed in addition to direct photoionization of the He droplets.
View Article and Find Full Text PDFDecoupling Carrier Dynamics and Energy Transport in Ultrafast Near-Field Nanoscopy.
Nano Lett
January 2025
Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, California 94720, United States.
Ultrafast near-field optical nanoscopy has emerged as a powerful platform to characterize low-dimensional materials. While analytical and numerical models have been established to account for photoexcited carrier dynamics, quantitative evaluation of the associated pulsed laser heating remains elusive. Here, we decouple the photocarrier density and temperature increase in near-field nanoscopy by integrating the two-temperature model (TTM) with finite-difference time-domain (FDTD) simulations.
View Article and Find Full Text PDFPhotoinduced Fröhlich Interaction-Driven Distinct Electron- and Hole-Polaron Behaviors in Hybrid Organic-Inorganic Perovskites by Ultrafast Terahertz Probes.
ACS Nano
January 2025
School of Information Science and Technology and Department of Optical Science and Engineering and Key Laboratory of Micro and Nano Photonic Structures (MOE), Fudan University, Shanghai 200433, China.
The formation of large polarons resulting from the Fröhlich coupling of photogenerated carriers with the polarized crystal lattice is considered crucial in shaping the outstanding optoelectronic properties in hybrid organic-inorganic perovskite crystals. Until now, the initial polaron dynamics after photoexcitation have remained elusive in the hybrid perovskite system. Here, based on the terahertz time-domain spectroscopy and optical-pump terahertz probe, we access the nature of interplay between photoexcited unbound charge carriers and optical phonons in MAPbBr within the initial 5 ps after excitation and have demonstrated the simultaneous existence of both electron- and hole-polarons, together with the photogenerated carrier dynamic process.
View Article and Find Full Text PDFA Cost-Effective Computational Strategy for the Electronic Layout Characterization of a Second Generation Light-Driven Molecular Rotary Motor in Solution.
J Comput Chem
January 2025
Scuola Superiore Meridionale, Napoli, Italy.
Light-driven molecular rotary motors are nanometric machines able to convert light into unidirectional motions. Several types of molecular motors have been developed to better respond to light stimuli, opening new avenues for developing smart materials ranging from nanomedicine to robotics. They have great importance in the scientific research across various disciplines, but a detailed comprehension of the underlying ultrafast photophysics immediately after photo-excitation, that is, Franck-Condon region characterization, is not fully achieved yet.
View Article and Find Full Text PDFCapturing the Elusive Curve-Crossing in Low-Lying States of Butadiene with Dressed TDDFT.
J Phys Chem Lett
January 2025
Department of Physics, Rutgers University, Newark 07102, New Jersey, United States.
A striking example of the need to accurately capture states of double-excitation character in molecules is seen in predicting photoinduced dynamics in small polyenes. Due to the coupling of electronic and nuclear motions, the dark 2Ag state, known to have double-excitation character, can be reached after an initial photoexcitation to the bright 1Bu state via crossings of their potential energy surfaces. However, the shapes of the surfaces are so poorly captured by most electronic structure methods, that the crossing is missed or substantially mis-located.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!