Perovskites have gained popularity both as the active material in photovoltaics and as bulk triplet sensitizers for solid-state triplet-triplet annihilation upconversion (TTA-UC). Prior to widespread implementation into commercial photovoltaics, an in-depth understanding of the environmental influences on device performance is required. To this point, the temperature-dependent structure-function properties of TTA-UC within methylammonium formamidinium lead triiodide (MAFA)/rubrene UC devices are explored. A strong temperature dependence of the underlying UC dynamics is observed, where the maximum UC efficiency is achieved at 170 K, reflecting the competition between triplet diffusion length, diffusion rate, and triplet-triplet encounter events. A combination of spectroscopic and structural methods and theoretical modelling illustrates that despite the significantly increased carrier lifetime of the perovskite at low temperatures, the TTA-UC dynamics are not governed by the underlying sensitizer properties but rather limited by the underlying triplet diffusion.
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http://dx.doi.org/10.1039/d3nr04446g | DOI Listing |
J Phys Chem B
December 2024
Centre for Biomedical Engineering, Indian Institute of Technology, Delhi 110016, India.
Dexter energy transfer (DET) of triplet electronic states is used to direct energy in photovoltaics, quench reactive singlet oxygen species in biological systems, and generate them in photodynamic therapy. However, the extent to which repeated DET between aromatic residues can lead to triplet energy migration in proteins has not been investigated. Here, we computationally describe DET rates in microtubules, actin filaments and the intermediate filament, vimentin.
View Article and Find Full Text PDFChem Sci
December 2024
University of Gothenburg, Department of Chemistry and Molecular Biology Medicinaregatan 7B 41390 Gothenburg Sweden
Triplet-triplet annihilation photon upconversion (TTA-UC) combines the energy of two photons to provide one of higher energy that can be used to drive photochemical or photophysical processes. TTA-UC proceeds at high efficiencies in dilute solution, but in solid state the efficiency drastically reduces. This is because exciton diffusion, compared to molecular diffusion in solid annihilator films, suffers concentration induced quenching, undermining efficient emission.
View Article and Find Full Text PDFClin Proteomics
December 2024
Division of Affinity Proteomics, Department of Protein Science, KTH Royal Institute of Technology, SciLifeLab, Stockholm, Sweden.
Background: The effect of varying brain ventricular volume on the cerebrospinal fluid (CSF) proteome has been discussed as possible confounding factors in comparative protein level analyses. However, the relationship between CSF volume and protein levels remains largely unexplored. Moreover, the few existing studies provide conflicting findings, indicating the need for further research.
View Article and Find Full Text PDFJ Chem Phys
November 2024
College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China.
Organic materials typically do not phosphoresce at room temperature because both intersystem crossing (ISC) and phosphorescence back to the electronic ground state are slow, compared to the nonradiative decay processes. A group of organic guest-host molecules breaks this rule. Their phosphorescence at room temperature can last seconds with a quantum efficiency of over 10%.
View Article and Find Full Text PDFBioresour Technol
October 2023
Department of Chemical Engineering, Motilal Nehru National Institute of Technology Allahabad, Prayagraj 211004, Uttar Pradesh, India. Electronic address:
Millets and millet crop residues are gaining increasing attention. Present work provides insights into thermal degradation characteristics, pyrolysis indices, kinetic triplets, and thermodynamic parameters for pearl millet straw (PMS) pyrolysis. Pyrolysis indices revealed suitability of higher heating rates for PMS in terms of enhanced pyrolysis performance and shorter reaction time.
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