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Imaging Fibrillar Collagen with Optical Microscopy
Published in Jiro Nagatomi, Eno Essien Ebong, Mechanobiology Handbook, 2018
Tong Ye, Peng Chen, Yang Li, Xun Chen
In spectroscopy, a useful approach to understanding the details of the excitation and emission process is to use a Jablonski diagram (Figure 6.2), first conceived by Alexander Jablonski in the 1930s. In the Jablonski diagram, energy levels of electronic and vibrational states of a molecule are indicated by horizontal lines. S0 is the ground state and represents the energy of a molecule that is not being excited by light. S1 and S2 are excited singlet states. The singlet state is an energy level at which the excited electron does not flip its spin state (+½ or −½); however, if a pair of nonbonding electrons are involved in excitation and the excited electron has its spin parallel to the paired electron, triplet states exist. Almost all the fluorophores have both singlet and triplet states. At room temperature, nonexcited molecules are mainly confined to the lowest vibrational states of S0.
Fluorescence Spectroscopy and Its Implementation
Published in Helmut H. Telle, Ángel González Ureña, Laser Spectroscopy and Laser Imaging, 2018
Helmut H. Telle, Ángel González Ureña
From the conceptual point of view, a major breakthrough in the understanding of light absorption and emission by a molecule and, therefore, of the fluorescence emission dates to the early 1930s, nearly a century after the phenomenon of fluorescence was initially formulated. In those years, the Polish scientist Aleksander Jablonski developed a type of diagram—in its refined form nowadays widely known as a Jablonski diagram—to illustrate the various molecular processes that can take place after a molecule has been excited by light (Jablonski 1933, 1935), and distinguishing fast processes from resonant states and slow processes from metastable states. Incidentally, in those days, fluorescence times could already be measured quite accurately. For example, a measurement of fluorescence lifetimes of nanosecond duration was reported as early as the mid-1920s (Gaviola 1926).
Organic Small-Molecule Materials for Organic Light-Emitting Diodes
Published in Zhigang Rick Li, Organic Light-Emitting Materials and Devices, 2017
Shijian Su, Norman Herron, Hong Meng
The principle of the electronic processes in molecules can be schematically illustrated with the classical Jablonski diagram, which was first proposed by Prof. A. Jablonski in 1935 to describe absorption and emission of light. Figure 3.6 illustrates the electronic processes of the host–guest molecules.
Enhancement approaches for photothermal conversion of donor–acceptor conjugated polymer for photothermal therapy: a review
Published in Science and Technology of Advanced Materials, 2022
Thi-Thuy Duong Pham, Le Minh Tu Phan, Sungbo Cho, Juhyun Park
The main method of clarifying the energy transition processes in the photophysical process is achieved using the Jablonski diagram, which explicitly displays the preferable mechanism of energy release following the excitation of a particular molecule. Low fluorescence emitters are complemented by energy decay in the form of heat de-excitation, allowing them to be employed as PA imaging probes and PTT agents for tumor ablation. CPs contain a delocalized electronic structure and long π-conjugation in their backbone; thus, their transited energy is controlled by various intramolecular and intermolecular interactions related to the special features of chemical structure and morphology characteristic. Understanding structure-property relationship is important and must be considered when designing the molecular structure and aggregated state of CPNs, which is an ongoing investigation [38].