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WorksheetsPhotonics NCs
Total questions: 15
Worksheet time: 15mins
A colloidal synthesis of nanocrystals doesn't allow to
NPs with approximately the same size or narrow distribution of sizes
NPs with the same shape and topology of their surface
NPs with the same chemical composition and lattice structure
Obtaine a thin NC film on substrates
The efficient band gap energy of NCs ... due to the size of a quantum dot decreases
Increases
Decreases
Does not change
Quantum dots of the first type are QDs characterized with
A large-gap semiconductor is grown onto a narrow-gap semiconductor core (оболочка из полупроводника с большой шириной запрещенной зоны наращивается на ядро из полупроводника с меньшей шириной запрещенной зоны)
A narrow-gap semiconductor is grown onto a large-gap semiconductor core (оболочка из полупроводника с меньшей шириной запрещенной зоны наращивается на ядро из полупроводника с большей шириной запрещенной зоны)
The energy levels of an electron and a hole in the shell are located lower than in the nucleus; in this case, the band gap of the shell is approximately the same as that of the core (энергетические уровни электрона и дырки в оболочке располагаются ниже, чем в ядре; при этом ширина запрещенной зоны оболочки примерно такая же, как у ядра)
The energy levels of an electron and a hole in the shell are located higher than in the nucleus; in this case, the band gap of the shell is approximately the same as that of the core (энергетические уровни электрона и дырки в оболочке располагаются выше, чем в ядре; при этом ширина запрещенной зоны оболочки примерно такая же, как у ядра)
Which process has the highest rate?
Phosphorescence
Fluorescence
Intercombination conversion
Vibrational relaxation
Photon radiation occurs only from the lowest excited state S1 or T1.
Levshin's rule
Stokes-Lommel rule
Kasha's rule
Vavilov's law
The emission spectrum of molecule doesn’t depend on the exciting light frequency.
Levshin's rule
Stokes-Lommel rule
Kasha's rule
Vavilov's law
What type of delayed fluorescence does not exist?
E-type
N-type
P-type
The quantum yield of luminescence is a ratio of...
the number of absorbed photons to the number of emitted photons
the number of emitted photons to the number of absorbed photons
the number of emitted photons to the number of incident photons
In nanoplatelets, the charge confinement occurs in ...
one direction
two directions
three directions
A decrease in the size of a quantum dot ...... its luminescene band position.
leads to a shift to shorter wavelengths
leads to a shift to longer wavelengths
doesn't change
Förster resonant energy transfer occurs ...
with photon emission
without photon emission
only at short distances (up to 10 Å)
The confinement effect occurs in ... in quantum dots.
one direction
two directions
three directions
The presence of a thick shell in quantum dots ...
reduces blinking
does not affect blinking
makes them more effective as a charge donor
Fluorescence is the radiative transition from ... to the ground state of a molecule.
the first excited singlet state
any excited singlet state
any excited state
The kind of impact of a quencher (Q) on an excited nanocrystal (NC*): Q presents in large excess, so there is a high probability of finding NC* and Q molecules at a distance where their interaction is significant. Mutual collision of NC* and Q is not required during the lifetime of the excited state. (Q присутствует в большом избытке - высока вероятность нахождения молекул NC* и Q на расстоянии, где взаимодействие значительно. Не требуется взаимного столкновения NC* и Q за время жизни возбужденного состояния.)
Static quenching
Long-range nonradiative energy transfer
Dynamic quenching
