UV laserAmazon

Thermally Activated Delayed Fluorescence (TADF) is a mechanism by which triplet state electrons can be harvested to generate fluorescence.

UV laserinvisible

The HOMO-LUMO model is comparable to the conductance-valance band model sometimes used to explain fluorescence in quantum dots.

The fluorescence of these molecules can be explained in terms of transitions of electrons between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of a molecule.

Online orders to can only be placed in . For other payment methods, request a quote or send a purchase order to info@ossila.com to purchase via offline channels.

UV laserengraver

Fluorescence is a type of luminescence, a process where energy is released from a chemical compound via the emission of a photon. This process happens through the transition of electrons between energy levels.

UV laserlight

Proteins that fluoresce naturally have conjugated organic groups in their structure that are able to absorb photons. Fluorescent tags can be added to proteins that are not naturally fluorescent to allow them to fluoresce. The fluorescent tags added to proteins are most often conjugated organic molecules, however quantum dots can also be used as fluorescent tags.

The transfer of an electron from the HOMO to the LUMO happens after the absorption of energy by the molecule. During this transition the electron is promoted from the S0 ground state energy level to the S1 excited state energy level. Fluorescence happens when an electron transitions from the LUMO to the HOMO of a molecule, where the electron relaxes from S1 to S0 and emitting a photon in the process.

UV laserwikipedia

In the ground state, S0, the electrons are in the lowest energy electronic state. When the molecule absorbs energy, an electron is promoted from S0 to the singlet electronic excited state, S1. The electron then can relax from S1 to S0 via a variety of processes. Fluorescence is a radiative transition of an electron from the excited state S1 to the ground state S0.

The vibrational state of an electron, Vn, is the vibrational energy level that the electron sits in within the electronic energy level.

Fluorophores fluoresce through the transition of electrons between different energy levels of a compound. Fluorophores such as quantum dots and conjugated organic molecules have electrons that can be easily promoted to an excited state. Their electrons can be promoted easily due to unique features of their chemical structures. The increased ability of their electrons to be excited then increases the number of photons released via fluorescence.

Conjugated molecules have alternating double bonds meaning their bonds are delocalized into shared electron clouds. The delocalisation of electrons results in a smaller HOMO-LUMO energy gap, meaning the promotion of an electron from the HOMO to the LUMO is easier. The structure of the conjugated system can change the size of the HOMO-LUMO gap, allowing the properties of the molecules to be tuned, similarly to quantum dots.

UV laserweapon

Fluorescence and phosphorescence are types of photoluminescence. Photoluminescence refers to radiative emissions where the absorbance of a photon is followed by the emission of a lower energy photon.

UV laserdiode

UV laserwavelength

Fluorophores have applications in electronic devices, and in biological and medical research. Their optical, physical, and chemical properties can be exploited in scientific applications. The optical properties can be useful as a light source, or in medical imaging, for example where there are difficulties seeing what is happening in the body. The transfer of electrons that happens in fluorophores can be used in devices where semiconducting layers are necessary, or to measure distances between atoms using Förster Resonance Energy Transfer (FRET). FRET is an energy transfer between two compounds that absorb and reemit light.

In electronics, fluorophores are used as semiconducting layers and light sources in a range of electronic devices, such as:

Which energy levels electrons move between governs the type of transition that occurs. Fluorescence is one of the processes of photon emission from a chemical compound. These transitions can be radiative or non radiative. Radiative transitions result in the emission of a photon, which is called luminescence. Non-radiative transitions release energy in other ways, for example molecular vibration.

The strength of fluorescence emitted by a chemical compound can be measured using fluorescence spectroscopy. The strength of fluorescence is characterized by the compound's quantum yield and extinction coefficient. The quantum yield of a chemical compound is the amount of photons emitted divided by the number of photons absorbed. The extinction coefficient measures how strongly a chemical compound absorbs light. Fluorescence spectroscopy is commonly used in bioscience and chemistry to analyse samples and measure the amount of unwanted chemical compounds in the environment.

A fluorophore is a chemical compound that is fluorescent, meaning it emits strong glowing colours. There are three key groups of chemical compounds that can fluoresce:

Changing the size and structure of a quantum dot changes its electrical and optical properties: as the size of a quantum dot increases, the HOMO-LUMO gap decreases. This allows the properties of quantum dots to be tuned, and therefore its fluorescence wavelength to be changed.

It looks like you are using an unsupported browser. You can still place orders by emailing us on info@ossila.com, but you may experience issues browsing our website. Please consider upgrading to a modern browser for better security and an improved browsing experience.

The structure of fluorophores can vary significantly depending on the type of fluorescent chemical compound in question. Several key types of chemical compounds can fluoresce, including quantum dots, conjugated organic molecules, and proteins.