What is meant by upconversion?
Definition: a process where light can be emitted with photon energies higher than those of the light generating the excitation.
What is RF mixer function?
An RF (or IF) mixer (not to be confused with video and audio mixers) is an active or passive device that converts a signal from one frequency to another. It can either modulate or demodulate a signal.
What are up and down conversions?
The up converted photon has sufficient energy to bridge the solar cell band gap and can be absorbed. Down-conversion is the process by which one high energy photon, which is inefficiently absorbed by the photovoltaic cell due to thermalisation losses, is converted into two or more lower energy photons.
What is anti-Stokes luminescence?
Anti-Stokes shift luminescence is a special optical process, which converts long-wavelength excitation to short-wavelength emission. The anti-Stokes shift luminescence signal can also be distinguished from the auto-fluorescence of biological tissues, thus reducing background interference during bioimaging.
What is triplet sensitization?
Optical upconversion via sensitized triplet-triplet exciton annihilation converts incoherent low-energy photons to shorter wavelengths under modest excitation intensities. When excited at λ = 808 nm, two excitons in the sensitizer are converted to one higher-energy state in the emitter at a yield of 1.2 ± 0.2%.
What is RF converter?
RF upconverters are designed to convert microwave signals to a higher frequency range. By contrast, RF downconverters are designed to convert microwave signals to. an intermediate frequency (IF). RF upconverters and RF downconverters that can upconvert or downconvert the frequency of a signal are also available.
What is IF and RF?
An RF (or IF) mixer (not to be confused with video and audio mixers) is an active or passive device that converts a signal from one frequency to another. These three ports are the radio frequency (RF) input, the local oscillator (LO) input, and the intermediate frequency (IF) output.
How is photon upconversion related to anti-Stokes emission?
Photon upconversion belongs to a larger class of processes by which light incident on a material induces anti-Stokes emission. Multiple quanta of energy such as photons or phonons are absorbed, and a single photon with the summed energy is emitted.
Which is the correct definition of photon upconversion?
Photon upconversion ( UC) is a process in which the sequential absorption of two or more photons leads to the emission of light at shorter wavelength than the excitation wavelength. It is an anti-Stokes type emission.
How is upconversion achieved in self assembled materials?
Broadly, upconversion is any process whereby low energy light is converted into higher energy light. Several distinct processes can result in upconversion, depending on the type of material [29]. However, in self-assembled materials, upconversion is generally achieved via the triplet–triplet annihilation (TTA) mechanism [30], [31].
How is photon upconversion a bimolecular energy transfer process?
Sensitized triplet-triplet annihilation (sTTA) based photon upconversion is a bimolecular process that through a number of energy transfer steps, efficiently combines two low frequency photons into one photon of higher frequency.