Energy transfer can occur in the samefreedomOr between different degrees of freedom.For example, the collision where only translational translational energy exchange occurs isElastic collision。
Other energy transfer modes include:turn-Translation, rotation rotation, vibration vibration, vibration translation, vibration rotation, etc. are in the samePotential energy surfaceEnergy transfer and electron translation, electron vibration and electron electron related speciesElectronic stateVariable energy transfer.
Energy transfer can occur in the same degree of freedom or between different degrees of freedom.For example, the collision where only translational translational energy exchange occurs isElastic collision。
Other energy transfer modes include: rotation translation, rotation rotation, vibration vibration, vibration translation, vibration rotation, etcPotential energy surfaceEnergy transfer and electron translation, electron vibration and electron electron related speciesElectronic stateVariable energy transfer.
characteristic
Announce
edit
Characteristics of energy transmission
everythingmaterialHeight ofenergyIt always actively transmits to the same kind of low-energy materials, and low-energy materials can only passively absorb the same kind of high-energy.
The second is the transformation and progressive transmission of material and energytransmit。
Third, material energy is at the same levelmediumIt is easy to transmit in the medium, but the transmission ability in the superior medium is poor, and it is not easy to transmit in the subordinate medium
Fourth, energy transfer must be carried out byparticleAs a medium, the wave transmission takes the form of“wave-particle duality ”。Because energy can't leavematerialSo energy can only be transferred in the particles of matter.
Factors affecting energy transfer
The size of energy transfer of matter and itsqualityandwaveOffrequencyIs proportional.CorporealqualityLargerfrequencyThe higher the energy is, the greater the energy will be transferred; on the contrary, the energy will be small.
Energy transfer up conversion
Announce
edit
Energy Transfer Upconversion (ETU) The study of energy transfer upconversion began in 1966. Auzel proposed that energy transfer process can occur between excited rare earth ions, which made people realize that upconversion luminescence can be achieved through energy transfer.Before that, people's understanding of the energy transfer phenomenon has been limited to the energy transfer from excited state ions to ground state ions.Since the efficiency of ETU process is relatively high, energy transfer and upconversion luminescence can be realized through the action of excitation light sources such as photodiodes, without relying on laser excitation.[1]
ETU isIonsThe up conversion luminescence process caused by the interaction between the same ions can also occur between different ions.Early research on ETU mostly focused on different ions, and then gradually developed to the same ions.According to different energy transmission modes, ETU can be divided into the following forms:
(a) Successive Energy Transfer (SET) Continuous energy transfer generally occurs between different types of ions.An ion in the excited state (donor ion) interacts with another ion in the ground state (acceptor ion) to meet the requirements of energy matching. The donor ion transfers energy to the acceptor ion to make it transition to the excited state, and returns to the ground state without radiative relaxation.The acceptor ion located at the excited state level transitions to a higher excited state level through the second energy transfer process.This mode of energy transmission is called continuous energy transmission up conversion.
(b) Cooperative Sensitization Upconversion (CSU) The cooperative sensitization upconversion (CSU) process is the interaction between three ions. Two excited rare earth ions simultaneously transfer energy to the luminescence center, making it jump to a higher excited state energy level, and the two ions return to the ground state through non radiative relaxation.
(c) Cooperative Luminescence,COL) cooperative luminescence (COL) process, two excited rare earth ions return to the ground state and emit short wavelength light at the same time without the participation of the third ion. Its obvious feature is that the energy of the emitted light is twice that of the de excited ion, and there is no energy level matching the energy of the emitted photon, which is an important difference between it and SET and CSU processes.
(d) Cross Relaxation (CR) The cross relaxation (CR) process can occur between the same or different rare earth ions.Two ions in the excited state, one of which transfers energy to the other to make it jump to a higher energy level, while itself relaxes to a lower energy level through radiation free relaxation.Unlike ESA, ETU is the interaction between ions, so it strongly depends on the concentration of ions. The doping concentration of rare earth ions must be high enough to ensure the occurrence of energy transfer.The mismatch of energy in the process of energy transmission can be determined byphononAuxiliary compensation[2]。
