Night Vision Goggles Monocular

Semiconductor electrode refers to the electrode system composed of semiconductor materials and appropriate electrolytes. When the semiconductor is in contact with the electrolyte, its residual charge is distributed in the electrode surface layer, forming a space charge layer similar to the ion double layer in the solution. The holes and electrons generated by the semiconductor electrode excited by light have strong oxidizing and reducing properties respectively, and can undergo redox reactions with the electrolyte solution. At the same time, the holes and electrons are separated in the space charge region, generating an electromotive force, forming a loop with the counter electrode, and forming a photoelectrochemical cell.

There are many differences between semiconductor electrodes and conductor electrodes, which determine a series of characteristics of semiconductor electrode reactions or the characteristics of the kinetic process of charged particles migrating at the semiconductor/solution interface. These differences are mainly manifested in:

① The concentration of carriers in semiconductors is much lower than that in metals, and it is easy to change the concentration. The electron concentration in the metal conductor body is 1028/m3, and the residual charge on the electrode surface is on the order of 1018~1019/m3, which is much less than that in the body, while the free electron concentration in semiconductors is about 1021/m3. When there is residual charge on the electrode, for metals, this part of the residual charge is all concentrated on the electrode surface, but the residual charge of semiconductors is dispersed in the space charge layer.

② Due to the above characteristics, a large part of the potential difference between the semiconductor and the solution interface will fall on the space charge layer, and the potential of the compact layer in the solution accounts for a very small proportion of the entire potential difference in the interface area), and it causes the energy band close to the electrode surface to bend.