Modelling absorption and photoluminescence of TPD

Asymmetry between Absorption and Photoluminescence Line Shapes of TPD: Spectroscopic Fingerprint of the Twisted Biphenyl Core

“…For both isomers, the twisting in the electronic ground state is quite pronounced, as shown by the large value of the central dihedral angle. The twisted geometry obtained with B3LYP/DZ is in a good agreement with the results of previous DFT calculations. ,, However, the calculated shape does not correspond precisely to the experimental structure in a crystalline environment, as obtained by X-ray diffraction measurements on single crystals . In the crystalline phase, the peripheral wings adopt considerably different conformations, thus breaking the C 2 symmetry that the free molecule can realize.…”

“…For that purpose, we extended our previous analysis of structural, energetic, and optical properties of TPD based on Hartree-Fock and related techniques such as configuration interaction of singles (CIS) to methods relying on DFT. 21,22 In addition to performing a series of absorption and PL measurements at room temperature, we have used Raman spectroscopy to analyze the coupling between electronic excitations and internal vibrations. The high-frequency Raman-active modes contribute to the vibronic progression observed in PL, whereas the elongation of low-frequency modes results in a substantial broadening of the vibronic subbands defined by the high-frequency modes.…”

“…Concerning the geometric structure and the frontier orbitals, some calculations have been performed using density functional theory (DFT), focusing on the hole-transport properties in the crystalline phase. − The objective of the present work was to analyze the optical properties of TPD with an ab initio interpretation of the experimentally observed Stokes shift, directly related to the possibility of observing stimulated emission even at high concentration. For that purpose, we extended our previous analysis of structural, energetic, and optical properties of TPD based on Hartree−Fock and related techniques such as configuration interaction of singles (CIS) to methods relying on DFT. , …”

Создание И Исследование Органических Светоизлучающих Структур, Содержащих Массивы Коллоидных Квантовых Точек-=sup=-*-=/Sup=-

“…Данные спектры демонстрировали, что положения максимумов пиков спектров ФЛ соединений TPD и Alq3 соответствуют длинам волн 395 и 525 nm соответственно. Полученные спектры практически идентичны классическим спектрам этих материалов, представленным в литературе [10,11]. Полуширины спектров ФЛ соединений TPD и Alq3 были весьма невелики -100 и 50 nm соответственно, что также говорит о высоком качестве полученного материала.…”

Chemical synthesis and surface modification of ZnO nanocrystals for bio-imaging

“…Chapter Two: Literature Review studied the PL emissions using a high quality ZnO bulk crystal at various temperatures, and modelled the observed two adjacent emission fine lines in each PL spectrum by employing the multimode Brownian oscillator (MBO) model. Although a few other models have been reported for modelling optical materials, such as the Gaussian model [87], Hartree-Fock (HF) and density functional theory (DFT) methods [88], and a simple Poission distribution model [89], the most recognized model is the MBO as it is a more comprehensive model that takes into account both the electron-LO phonon coupling and the dissipative effect of phonon-bath. Excellent agreement between this theory and experimental results was achieved on bulk ZnO.…”