The concept of organic solar batteries looks like a very new, but in fact, history does not fail – with the history of similar silicon-based solar batteries. The first silicon-based solar Laptop batteries is a Bell Labs was created in 1954, and its photovoltaic conversion efficiency is about 6%, while the first device is an organic photoelectric conversion by Kearns and Calvin established in 1958, the main material Magnesium phthalocyanine (MgPc) dyes, the dye layer is sandwiched between two electrodes of the work function between different files. In this device, they observed the open circuit voltage of 200 mV, the photoelectric conversion efficiency of low are embarrassed to speak. Start the beginning of the sentence Gao Xia Li

After 20 years, innovation in the field of organic solar batteries much, all the device structures reported are similar to the 1958 edition, only two changes of work function between different electrode materials in organic semiconductor variety. The principle of these devices are presented in Figure 1: organic semiconductors in light of the electronic energy levels are delighted homo the LUMO energy level, resulting in a pair of electrons and holes. Electronics is an occupation with low extraction electrode, the hole was from electrodes with high functionality infill electronic form and a photocurrent under the illumination. In theory, the film organic semiconductors and operate two different working electrode contact will result in a different Schottky barrier. This is the charge Photoinduced may be addressed to move from base. And therefore such a structure, the Dell Inspiron 1420 battery is often called “Schottky-type solar batteries organic.

In 1986, the industry is facing a historic breakthrough. To achieve this breakthrough was a Chinese, Kodak, Dr. Deng Qingyun. This era of organic solar batteries used in organic materials, mainly with high efficiency visible light absorption of an organic dye. These dyes are generally used as photosensitive materials, which naturally forces Kodak. Deng Albatron device in the basic structure is a kind of perylene tetracarboxylic derivatives (Tang and former call PV) and copper phthalocyanine (CCEP), consisting of bilayer. Bilayers is the essence of a heterojunction, Deng is the old idea of two kinds of semiconductor materials to mimic organic inorganic heterojunction solar batteries. He has prepared solar batteries, the photoelectric conversion efficiency of around 1%. Even if they are even worse with silicon batteries, but compared to previous Schottky-type battery is a great improvement. It is a fruitful idea to search for organic solar batteries has opened a new path now that the structure of the bilayer heterojunction organic research solar Dell Inspiron 1501 battery is still one of the keys.

Bilayer-type structure heterojunction organic solar battery shown in Figure 2. As the semiconductor material organic body after absorption of photons generated hole – electron pairs, the electron injection materials in organic semiconductor as a receiver, the hole and electronics were isolated. In this system, the p-electron donor, electron acceptor, compared to n-type, hole, and electronic transmission to the two electrodes, respectively, forming photocurrent. And the above “Schottky-type batteries” with the characteristics of these structures is the introduction of a mechanism for charge separation. Compared to the interaction of semiconductor silicon, organic molecules are much smaller between the different molecules and the HOMO and LUMO can not be combined to form a continuous phase in the whole body of the conduction band and the valence band. Carrier transport in organic semiconductors need to load different molecules by a “jump” mechanism for achieving macro-economic performance is the carrier mobility is much lower than in inorganic semiconductors. At the same time, small organic molecules have been excited by absorption of photons can not be done in silicon produced in the conduction band and free electrons leave a hole in the valence band. Optical excitation of small organic molecules, the electrostatic interaction arising through a combination of hole – electron pairs, which is commonly called “excitons (exciton). The existence of excitons limited time, typically on the order of magnitude less than a millisecond, without complete separation of electrons and holes are complex (recombinant), released its energy absorption. Clearly, the isolation of the free electron and hole excitons, light current does not contribute. Yi Gu organic semiconductor in the exciton separation efficiency of the conversion efficiency of opto-electronic Dell Inspiron 1520 battery has a crucial impact.

For the Schottky-type batteries, the separation efficiency of excitons is very problematic. Light-induced formation of excitons, only the diffusion layer in the Schottky junction in the area of the Festival on the electric field can be separated. Other places to form excitons, you must first be transferred into the diffusion layer may be formed in light of the current contribution. However, the migration of excitons in organic dye very limited range, usually below 10 nm. Therefore, most excitons into electrons and holes in the separation of composite lost before. In batteries heterojunction organic results, it is obviously increased the separation efficiency of excitons. The electrons in the LUMO energy level of molecules injected into excited levels of electron acceptor LUMO energy, this process is essentially the separation of the excitons. The interface between two layers of biofilm is not formed. In the process of preparation (thermal evaporation – deposition, or spin solution-coating method) two layers of film will always form an interpenetrating structure, and therefore greater surface interface. In the body of material to the body resulting from the phase of excitons, the dissemination can be more easily access the interface of two materials, electronic materials, the LUMO energy levels in the receiver to achieve charge separation. At the same time, many studies have shown that the equipment and receiver Dell Inspiron 1521 battery can absorb the frequency corresponding to the formation of exciton-photon, and then the hole in the HOMO energy level to the body of the material injected into the level HOMO energy in the file. Therefore, the exciton can simultaneously on both sides of the interface in the double membrane formation, and diffusion at the interface were isolated. In short, compared to the Schottky-type batteries, with donor assistance – receptor double-membrane structures can significantly improve the separation efficiency of excitons.

In 1992 the Turks Sariciftci (see Salic Karlovci) in the United States found that the state of electronic excitation can be very quickly from molecules of organic semiconductor injected into the C60 molecule (structure shown in Figure 3 ), while the reverse process is much slower. In other words, the semiconductor materials and organic C60 interface, the exciton can reach a very high rate of charge separation and charge separation after the compound at the interface is not easy . Because the C60 is a very large structure conjugate surface, the electrons in orbit by the 60 carbon atoms, the molecular composition of the track from the field, you can play an external mail stabilization effect. Therefore, C60 is a good acceptor of electrons materials. In 1993 Sariciftci on the basis of this discovery is made of heterojunction solar batteries PPV/C60 bilayer. PPV is generally called “poly styrene hold” is a conductive polymer (on conducting polymers will be detailed in another article), is also a typical P-type semiconductor material organic. Since then, with C60 as electron acceptor bilayer heterojunction solar Dell Inspiron 1525 battery after another.

Subsequently, researchers in such solar batteries based on the proposed also an important concept: the mixed heterojunction (bulk heterojunction). “Mixed Heterojunction (bulk heterojunction)” written in English “Bulk Heterojunction,” here is my own translation, it remains a fairly accurate sense of meaning. “Mixed Heterojunction (bulk heterojunction)” concept to the separation process of photoelectric conversion of excitons and transport the carrier in these two constraints. Double-layer film solar batteries, although both films have a larger area of interface, but the exciton is still only in the areas of surface separation, the distance from the interface of the exciton generated by the interface are not yet moved into the enclosure of the. And the rate of organic matter mobility carriers are generally very low at the interface between the gate electrode to the significant loss of movement in the process. These two limits of the dual membrane electro-optical conversion efficiency of the VGP-BPS10 battery.

The so-called “mixed heterojunction is a body of material and acceptor materials are mixed, through co-evaporation method or a spin-coating film made of a mixture. The structure shown in Figure 4, the donor and acceptor to form a mixed film where only one component of the region, including Blue represents the electron donor, electron acceptor yellow. Products at any exciton localization can be contacted via short path to the physical interface with the receiver (eg, surface galling), and therefore the charge separation efficiency has been improved. At the same time, the interface is formed on the load flow the child may also be a shorter way to reach the electrodes, and thus compensate for the shortcomings of the carrier mobility. To meet the requirements of the electrode must be selective electrode. In other words, when the donor and the negative contact, the donor can not be transmitted to the hole in the anode. In a mixed heterojunction, such as the contact is in fact inevitable.

Such a structure is naturally the ideal state of the entire phase donor can be put in contact with the cathode, while all receivers can be contacted at the anode. In the non-ideal state, unable to make contact with the cathode to the mass of the positive charge appears on can be transmitted to the battery on the positive, and therefore this structure is not perfect. However, compared to battery membrane bilayer, the effectiveness of these structures is also clear that organic solar batteries stored in batteries to more efficient hybrid heterojunction remain.

Affecting a major valve battery life

The normal life valve lead acid batteries for over 10 years, in theory, may be 20 years but in actual use often insufficient capacity, failure or early phenomenon. Affect the life of valve lead acid batteries of many factors, including:

1, the ambient temperature

The battery at 25 ℃ environment, availability of a longer life. Temperature, the battery will exacerbate corrosion of the plates at the same time will consume more water, thus reducing battery life, long term operating temperature if higher than 10 ℃, life is about halfway. Valve lead-acid IBM ThinkPad R51 battery changes in capacity with changes in temperature, 25 ℃ when the battery has a capacity of 100% at above 25 ℃, 10 ℃ for each increase in battery capacity would be halved .

Must be careful to do according to actual temperature changes to streamline construction lead-discharge battery acid present, while a battery compartment of the right to control the temperature kept at 22 ℃ ~ 25 ℃ or less.

2 overload

The long-term overload state, the cathode due to the reaction of oxygen evolution, the water is consumed, H + increase, which increases the acidity and near the cathode, the grid corrosion accelerated, causing thinning of the accelerated corrosion of the grid battery, battery capacity reduced, the same time due to water loss intensified, would have drained the danger of the Dell Inspiron 1501 battery, affecting the battery life.

3, an excessive discharge of

Excessive battery discharge occurred mainly in the AC power outage, the battery time to load. When the battery runs down its on-voltage is too low or zero, this will lead to a large number of sulfuric acid inside the battery lead is adsorbed on the surface of the cathode of battery, resulting in the cathode Battery “sulfate.” Lead sulphate is an insulator, its formation is related to the battery charge and discharge performance, have a tremendous negative impact, and therefore the formation of sulphate in the cathode, the higher the greater the internal resistance of batteries, the battery charge and discharge performance, the worse the shorter the lifespan of the battery.

4, the conditions of low discharge current, the impact of

In the discharge current small formed under the particle size of lead sulfate as the conditions of the large discharge current, the size requirements of mainstream higher than the rate of formation of crystals smaller than current conditions, slow the growth of crystals too late to be oxidized very rapidly reduced, and thus a relatively smaller size, whereas in conditions of low current, a crystal of lead sulfate great can be easily restored. Such that crystals of lead sulfate is not a long-term cleanup, will certainly affect the hp 338794-001 battery capacity and longevity. Therefore, the actual expense of the current battery capacity must be executed under a precise calculation.

5, the unbalanced nature of the impact of charge-discharge

The study results showed: composition of the grid alloy and structure in different parts of the distribution is different, leading to the unbalanced nature of the electrochemical properties grid [2], the imbalance is to turn in the float and the load condition of discharge voltage are different, and will be in charge and discharge cycle, so that this difference is increasing and training the so-called “rear battery (battery failure).” The current domestic standards in a group of toshiba PA3191U-2BRS battery float voltage difference between the largest to be ≤ 50mV, the norm in developed countries are ≤ 20mV, should pay attention to the battery and reduce floating state operating voltage differences.

6, thermal runaway phenomenon

As the use of depleted fluid valve regulated lead acid battery design, the infusion of battery electrolyte are adsorbed on the fiber glass, when the load current increases, it is necessary to leave the gas valve, which causes the loss of farm water resistance by significant volume reduction of the charge and discharge large amounts of heat generated in the process, which propagate the heat that the temperature has been taken too late, they will form a thermal runaway. Thermal runaway causes are not promptly reduced float voltage, lax safety valve or pressure valve is open too low, etc. In severe cases of thermal runaway if the landfill has the potential DIP apple A1008 battery voltage transient and Sustainable Housing battery temperature rose to 70 ℃ ~ 80 ℃, and therefore thermal runaway must be a high level of attention.

7, long-term impact of floating charge

Float charging status of battery in the long term, pricing and not the discharge is required to cause passivation of the anode of the battery flat, so that the battery internal resistance increases, the capacity is severely reduced, resulting a shortened life of the battery.

Second, improve the life of valve lead acid battery of measures

With this purpose the life valve lead-acid batteries of factor analysis to improve the life of valve lead acid batteries, we must do:

1 battery of stringent quality levels. In selecting the battery and the process of procurement, we must fully understand the production process manufacturer, manufacturing process and quality control, as well as specifications and so on, if necessary, require manufacturers to conduct the first in the capacity of experiments to screen a difference smaller IBM ThinkPad T40 battery.

A reasonable choice charger. Since the food was monitored over real time and intelligent management capabilities, allowing the battery sealed in the best condition always work, so use high quality switching power supply as a charging unit. High frequency switching power supply system, adopting modular design, when a module is a failure, should be able to immediately withdraw from the race does not affect the normal operation of other modules, module parts should be able AutoFill that batteries are not due to failures caused by excessive discharge module.