Kinetics of photo-charge transfer in bacteriorhodopsin

The different photoelectric signals in bacteriorhodopsin were experimentally measured when it was excited by 10 ns pulsed lasers at 1064 nm, 532 nm and 355 nm. 532 nm pulsed laser is used mostly as pumping light to measure the photoelectric signals affected by the impedance of the measuring circuit. The mechanism that bacteriorhodopsin generates photocharge and the photocharge transfer in it was studied and analyzed. The results show that the positive and negative photoelectric signals are produced by the shift of the positive and negative charge respectively, and more energy is needed to produce positive charge than negative charge. The positive and negative charge not only have their own transfer characteristics but also affect each other, such as positive charge moves slowly and negative charge moves fast, while the negative charge can pull the positive charge to move forward. These characteristics are related to the interfacial effect between the sample and electrodes so that the magnitude and width of the pulse photovoltage are different from that of other photoelectronic devices on the linked resistance.