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Information × Registration Number 0225U000660, (0123U102728) , R & D reports Title Persistent luminescence - a new paradigm for innovative applications of organic semiconductor systems popup.stage_title Дослідження пасткових станів, включаючи глибокі пастки, в системах, що демонструють О-ДПЛ, на основі донорно-акцепторних композитів і безексиплексних дво- та трикомпонентних композитів. Head Kadashchuk Andrii K., Кандидат фізико-математичних наук Registration Date 15-01-2025 Organization Institute of Physics of National Academy of Sciences of Ukraine popup.description1 The main goal of the research is to comprehensively study the mechanisms of physical processes that cause the emergence of long-term persistent luminescence of organic systems (O-PL), which means the "accumulation" of energy in photoinduced long-lived states with spatially separated charge pairs and is a new phenomenon for organic semiconductors, forming a promising area of their application. The elucidation of the complex mechanism of O-PL is aimed at improving the characteristics of such organic systems for use in flexible optoelectronics devices. popup.description2 The role of charge traps in pure substances and matrix-dopant composite systems based on amorphous organic materials of different chemical nature, in which the concentration of DMAC-TRZ dopant varied from 0.1 to 50%, was investigated by thermally stimulated luminescence and stationary spectroscopy. It has been shown that DMAC-TRZ forms relatively shallow traps for charge carriers in the mCBP matrix and rather deep charge traps in UGH3 and DPEPO, with the criterion of trap depth being the triple width of the density distribution function of local charge states of the matrix. It was first demonstrated that for shallow traps, the activation energy for the release of charge carriers does not correspond to the actual trap depth and increases significantly with an increase in the impurity concentration up to 3%, then decreases at a trap concentration of more than 10%, when a transition to the regime of charge carrier transfer exclusively through trapped states occurs. The trapping of charge carriers in such systems is a cumulative effect of the intrinsic disorder of the matrix and extrinsic traps formed by impurities, which can be quantitatively described within the concept of “effective” energy disorder. In the case of deep traps, the release energy of charge carriers accurately reflects the actual depth of the trap at impurity concentrations up to 3%, but already at impurity concentrations of 1% and above, in addition to the transfer of trapped carriers to matrix molecules, their release is observed through direct transfer to trapped states, which is the first experimental confirmation of the essential role of the “super-exchange” electron transfer mechanism, which was previously theoretically predicted for systems with deep traps. Product Description popup.authors Vakhnin Oleksandr Yu. Kadashсhuk Andrii K. popup.nrat_date 2025-01-15 Close