Revealing Exciton and Metal–Ligand Conduction Band Charge Transfer Absorption Spectra in Cu-Zn-In-S Nanocrystals

The article simulates the optical absorption spectra (OAS) of endohedral complexes Er2C2 @ C90 based on isomers No. 44 (C2) No. 21 (C1) of fullerene C90. For this purpose, the energy spectra of the indicated isomers have been calculated. The calculation was carried out within the framework of two models. Within the framework of the first model, which is traditional, only hops of π-electrons from site to site were taken into account (the integral of hopping to the nearest sites B ~ -2.6 eV). Within the framework of the second model, developed in a series of our works [1-5], in addition to hopping from site to site (the integral of hopping to the nearest sites B ~ -1.0 eV), the intrasite Coulomb interaction (ICCI) of π-electrons was also taken into account (the integral of the Coulomb interaction U ~ 7.0 eV). Comparison of the OSS curves obtained by us with the experimental data [5] convincingly indicates that the second model adequately describes the OSS of the endohedral Er2C2 @ C90 complexes based on the investigated isomers. The magnitude of charge transfer from the Er2C2 system to the fullerene shell turned out to be -4e.

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Cation Sensing Capabilities of A Nitrophenyl Cinnamaldehyde Derivative

Molekul ◽

10.20884/1.jm.2020.15.3.654 ◽

2020 ◽

Vol 15 (3) ◽

pp. 191

Author(s):

Venty Suryanti ◽

Fajar Rakhman Wibowo ◽

Ahmad Marzuki ◽

Meiyanti Ratna Kumala Sari

Keyword(s):

Charge Transfer ◽

Organic Compound ◽

Charge Density ◽

Absorption Spectra ◽

Color Change ◽

Metal Cations ◽

Colorimetric Sensing ◽

Color Changes ◽

Ligand Charge Transfer ◽

Cation Sensing

The cationic chemosensor based on organic compound bearing an aminophenol moiety as a receptor for metal analyte and a cinnamaldehyde moiety as chromophoric fragment has been developed. In this work, we report the colorimetric sensing of nitrophenyl cinnamaldehyde derivative, namely methyl-3-(2-hidroxy-5-nitrophenyl amino)-3-phenylpropanoate, towards a variety of metal cations, such as Cu2+, Fe3+, Ni2+ and Zn2+. The cation sensing abilities of the sensor were observed for Cu2+and Fe3+ with a color change from colorless to pink and faint yellow, respectively, The characteristic UV-Vis spectra changes were observed upon addition of Cu2+and Fe3+ cations. The hypsochromic absorption spectra shifts were obtained, indicating the cations and sensor complexations had formed. A metal-to-ligand-charge-transfer (MLCT) had occurred and the charge density of the sensor changed resulting in appearance of new absorption peaks in the UV-Vis spectra and color changes of the sensor solution upon addition of the Cu2+and Fe3+.

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Локализованные экситоны в спектре оптического поглощения оксида цинка, легированного марганцем

Физика твердого тела ◽

10.21883/ftt.2019.05.47573.09f ◽

2019 ◽

Vol 61 (5) ◽

pp. 817

Author(s):

В.И. Соколов ◽

Н.Б. Груздев ◽

В.А. Важенин ◽

А.В. Фокин ◽

А.В. Дружинин

Keyword(s):

Zinc Oxide ◽

Charge Transfer ◽

Absorption Band ◽

Optical Absorption ◽

Absorption Spectra ◽

Polarized Light ◽

Threshold Energy ◽

Impurity Absorption ◽

Charge Transfer Transitions ◽

Long Time

AbstractThe results of the study of optical absorption and EPR signals of single crystals of zinc oxide doped with manganese are presented. A broad impurity absorption band with the threshold energy about 2.1 eV, which was treated as a result of charge transfer transitions, has been observed for a long time in ZnO : Mn absorption spectra. In absorption spectra of a polarized light at 4.2 and 77.3 K, we first detected several lines of different intensity in a 1.877–1.936 eV range of energies of the light quanta. The observed lines are attributed to a donor exciton [( d ^5 + h ) e ] that emerges as a result of the Coulomb binding a free s electron and a hole, which is localized on p – d hybridized states. The EPR spectra of Mn^2+ ion signals, when corresponding to the impurity absorption band exposed to light, are found to be not photosensitive. The obtained results indicate that the ZnO : Mn impurity absorption is due to transitions from antibonding p – d hybridized DBH states to the conduction band.

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