The views of Chinese Medicine
Traditional Chinese medicine think teenagers premature white hair, often think of because of sadness, heat content, development raises a. Treat heat of appropriate cool, nourishing the liver and the kidney, Fang Xuan longevity to sesame balls, UFA pill cd. Medicinal raw Radix Angelica dahurica in various 150g, 100g, 80g, 200g of glossy privet fruit mulberry, 200g 200g, Herba ecliptae. Grind in all delicate last stage, honey pills, each pill 10g, 3 times daily, 1 pills each time.
2 medicine thinks, this disease is mainly due to liver and kidney deficiency, blood loss induced by. Congenital little bald more with genetic factors,johnson baby shampoo is not easy to treatment; then the little bald nature, in addition to the cause of treatment, but also should strengthen the nutrition. Experimental results show that, the lack of proteins and a high degree of malnutrition is white-haired etiology. Dietary deficiency of trace elements copper, cobalt, iron, can also lead to hair.
3 in addition to many diseases may be associated with presenile poliosis occurred, such as pernicious anemia, hyperthyroidism, cardiovascular disease ( myocardial infarction, atrioventricular bundle block, hypertension), dystrophic myotonia, vitiligo and Vogt - Koyanagi 's syndrome. In addition, the human mental status changes, such as long-term unhappy, is excessive or excessive emotional tension, fear will often causes hair to bleach quickly. The diseases and nutrition and mental factors will make strength, deadly gas, gas three loses balance, so that the hair damage, this is our words often say " hurt vitality". The occurrence of the hair without special treatment, only to find the cause and eradicate, can effect a radical cure.
Ze Wu Tang: clearing away heat and cooling blood, promoting blood circulation and removing blood stasis, nourishing liver and kidney, nourishing hair,JOHNSON Shampoo white hair is preferred for treatment of traditional Chinese medicine! Bamboo forest temple medicine that "hair is more than blood", the hair growth from blood in the barn. Wang Qi and blood, hair growth is normal. Qi and blood are not decline, Rong head of white hair.
Method of ginseng tonic vitality, Fumai originallies, strengthening spleen and lung, and soothe the nerves, puzzle, nourishing Tibetan Fu, Rong Qi and blood, hair wing hair; Angelica Huoxue Tiaojing, relieving pain, promoting blood circulation of Qi, Zhuyu new; Polygonum multiflorum and nourishing liver and kidney, beneficial essencehematic, cut malaria, detoxification, and blood gas black mustache, temples, Yuet color. Long wear long bones, benefit the essence, prolong the life of old main, deficiency of the kidney essence of Morinda officinalis how hair loss; Tonifying Kidney Yang, Qufeng desiccant.
The essence of kidney and bone, salty division,L-Carnitine hair person big help; Cistanche Yijing blood, kidney yang, laxative, raising the five, negative, Yi love gas; gastrodin endogenous wind Zhijing, repress the liver, expelling wind, Qi Nourishing Yin, blood circulation, strong gluten; Tu son of Yang and nourishing Yin, Tim lean pulp, Mingmu antidiarrheal, raising muscle, solid, strong female, Kennedy bones; black sesame blood tonic, Runzao slippery bowel, beneficial blood, hair beauty muscle.
2011年12月20日星期二
2011年12月19日星期一
pixel lines
1 increase in contrast
Unfortunately, adding extra contrast is one of the most neglected and abandoned technique.
Joost de Valk uses a thin high contrast edges, make it easy for the user to distinguish between different section of the page. In the figure above the larger part,Web Content Management System as you can see, most of the time this contrast is just a 1 pixel highlight line next to the 1 pixel lines.
However, this page" More" and" Go" buttons contrast is too small, even when you're looking for is also very easy to be ignored.
WordPress is the most popular links in the page" Download ( download )" use of colorimetry. The red in the cold gray page himself jumping out. But the red in lightness to convergence, avoids the effect of the whole page effect.
If you for the use of contrast shilly-shally, took this decision process as makeup. You have to do is not to let people yell" look,Website Development contrast!", you need is to come very naturally draw their attention to important items on the page, highlight the key already exists.
The 2 fade
Technology for the development of all want to use the gradient person offers a variety of creating gradient tool. But is that a good thing?
Media Temple site every page using a gradient, the gradient using the control and the exquisite design is the key to success. Logo, headlines,L-Carnitine buttons and backgrounds all have subtle or image gradient, with emphasis on the content. The most complex gradients used in the simple 120 pixels wide button (a page in the" ACTIVATE" and" LEARN MORE" ), because they require visitors to focus attention.
Commission Junction Media Temple gradient using far less detailed, but also uses overly abundant gradient type:
From black to gray level gradient linearity, located at the top of the page header office green radial gradient landing frame background of the " CJ" logo on top of the oblique gradient fuzzy input box background light vertical linear gradient navigation bar background vertical gradient Webinar ads bright linear gradient another vertical linear weakened, used in the headline is the design is a bit adventurous, most progressive useful, but some problems still exist. Most notably, no consistency. The same choice differentiability strong color combination as the reason, designers are needed for each project selection of suitable gradient composite.
Using the gradient, ensure good visual flow is very important: please keep the delicate use of gradient. The most important point, only when the whole design help to use the gradient.
Unfortunately, adding extra contrast is one of the most neglected and abandoned technique.
Joost de Valk uses a thin high contrast edges, make it easy for the user to distinguish between different section of the page. In the figure above the larger part,Web Content Management System as you can see, most of the time this contrast is just a 1 pixel highlight line next to the 1 pixel lines.
However, this page" More" and" Go" buttons contrast is too small, even when you're looking for is also very easy to be ignored.
WordPress is the most popular links in the page" Download ( download )" use of colorimetry. The red in the cold gray page himself jumping out. But the red in lightness to convergence, avoids the effect of the whole page effect.
If you for the use of contrast shilly-shally, took this decision process as makeup. You have to do is not to let people yell" look,Website Development contrast!", you need is to come very naturally draw their attention to important items on the page, highlight the key already exists.
The 2 fade
Technology for the development of all want to use the gradient person offers a variety of creating gradient tool. But is that a good thing?
Media Temple site every page using a gradient, the gradient using the control and the exquisite design is the key to success. Logo, headlines,L-Carnitine buttons and backgrounds all have subtle or image gradient, with emphasis on the content. The most complex gradients used in the simple 120 pixels wide button (a page in the" ACTIVATE" and" LEARN MORE" ), because they require visitors to focus attention.
Commission Junction Media Temple gradient using far less detailed, but also uses overly abundant gradient type:
From black to gray level gradient linearity, located at the top of the page header office green radial gradient landing frame background of the " CJ" logo on top of the oblique gradient fuzzy input box background light vertical linear gradient navigation bar background vertical gradient Webinar ads bright linear gradient another vertical linear weakened, used in the headline is the design is a bit adventurous, most progressive useful, but some problems still exist. Most notably, no consistency. The same choice differentiability strong color combination as the reason, designers are needed for each project selection of suitable gradient composite.
Using the gradient, ensure good visual flow is very important: please keep the delicate use of gradient. The most important point, only when the whole design help to use the gradient.
2011年12月18日星期日
physical weakness
Hair loss.
Hair has its own life, grow to a certain length, life end, it is to die a natural death, will naturally fall off, this is a normal phenomenon. This is the case for hair, anyone, but is often. Abnormal hair, because hair growth is affected. Hair growth need nutrition, and nutrition on blood delivery,johnson baby shampoo
if a person is long-term health, physical weakness, blood deficiency, poor nutrition, hair will be because of the lack of nutrition, growth is not good but short-lived shedding. It is easy to fall the hair, it is also more. There is life after a serious illness, the hair out sparse, it is perhaps for this reason.
Excessive use of the brain or people, often be preoccupied by some troubles, boredom, or experiencing something, the spirit is too tight, so that the brain has been a lot of stimulation, sometimes also can affect the hair nutrient supply and growth. Because all activities of the human body is the brain tube, suffered brain stimulation, activity disorderly feet, not normal to play a role, is bound to make the body nutrition stimulated, falling hair conditions. Some people experience what too excited, the brain by intense stimulation,JOHNSON Shampoo
spirit is not normal, sometimes overnight head hair to take off a large, people say "GuiTiTou", is actually so take off.
There were originally a hair growth growth and aging of the cycle, the natural physiological fact of hair loss every day. But there are also some hair loss is caused by pathological factors. To young people, is the more common alopecia areata, also known as " GuiTiTou", this is a because of stress, emotional, resulting in a block of scalp hair suddenly entered a growth stage, suddenly dropped light. This kind of case hair after treatment, three to five months to resume growth.
Reasons for hair fall with nutrition, and mental tension or sudden stimulation also has the very big relations, can be found in blood trace elements,L-Carnitine usually do not often in a nervous state. In the fall the hair place often use ginger rub, can promote hair growth, nutrition is comprehensive, appropriate to eat hard food, appropriate to eat black sesame.
Hair has its own life, grow to a certain length, life end, it is to die a natural death, will naturally fall off, this is a normal phenomenon. This is the case for hair, anyone, but is often. Abnormal hair, because hair growth is affected. Hair growth need nutrition, and nutrition on blood delivery,johnson baby shampoo
if a person is long-term health, physical weakness, blood deficiency, poor nutrition, hair will be because of the lack of nutrition, growth is not good but short-lived shedding. It is easy to fall the hair, it is also more. There is life after a serious illness, the hair out sparse, it is perhaps for this reason.
Excessive use of the brain or people, often be preoccupied by some troubles, boredom, or experiencing something, the spirit is too tight, so that the brain has been a lot of stimulation, sometimes also can affect the hair nutrient supply and growth. Because all activities of the human body is the brain tube, suffered brain stimulation, activity disorderly feet, not normal to play a role, is bound to make the body nutrition stimulated, falling hair conditions. Some people experience what too excited, the brain by intense stimulation,JOHNSON Shampoo
spirit is not normal, sometimes overnight head hair to take off a large, people say "GuiTiTou", is actually so take off.
There were originally a hair growth growth and aging of the cycle, the natural physiological fact of hair loss every day. But there are also some hair loss is caused by pathological factors. To young people, is the more common alopecia areata, also known as " GuiTiTou", this is a because of stress, emotional, resulting in a block of scalp hair suddenly entered a growth stage, suddenly dropped light. This kind of case hair after treatment, three to five months to resume growth.
Reasons for hair fall with nutrition, and mental tension or sudden stimulation also has the very big relations, can be found in blood trace elements,L-Carnitine usually do not often in a nervous state. In the fall the hair place often use ginger rub, can promote hair growth, nutrition is comprehensive, appropriate to eat hard food, appropriate to eat black sesame.
2011年12月15日星期四
food science
Baby food may also contain limited Staphylococcus aureus
Yangcheng Evening News reporter investigates the discovery, even the most stringent safety requirements of infant formula, the standard is not strict.
In April 1, 2011 the implementation of new national standard" infant formula for the national food safety standards", only to powdered infant formula of Staphylococcus aureus to make the request, but is still limited in a certain range. Similarly, in suitable for Staphylococcus aureus growth in dairy products," whey powder and whey protein powder of national food safety standards" and" milk powder" in the national food safety standards regulations can limit detection of Staphylococcus aureus. In a similar" cheese the national food safety standards" and" processed cheese" in the national food safety standards, requirements are similar to.
" Dispute between new and old" is a big deal
" Staphylococcus aureus events in China." raise a Babel of criticism of America, but FDA food bureau former deputy director David Acheson ( David Acheson ) is very surprised, he told the Yangcheng Evening News, the crowd 's half, skin and nose are Staphylococcus aureus, in raw meat, eggs, milk products in all natural presence of Staphylococcus aureus.
" We should pay attention to the toxin, but not Staphylococcus aureus." Acheson thinks, the quick-frozen food GB dispute between new and old is a big deal, the United States FDA related standards are strict requirements are not allowed in the presence of toxins. He thinks, food in Staphylococcus aureus usually does not cause disease, due to Staphylococcus aureus growth temperature is 6 - 48 DEG C, produce toxins that temperature is 10 - 45 DEG C, therefore, in the production process of its control in low level, when cooking food as long as the temperature reached 73.9 degrees, can be instant seckill Staphylococcus aureus.
The Chinese Institute of food science and technology director Meng Suhe's view, the big deal of dispute between new and old, led to the frozen food industry crisis, but its backside is industry of our country food trust crisis, how to get the trust of consumers, government and enterprises at present must face the problem.
Yangcheng Evening News reporter investigates the discovery, even the most stringent safety requirements of infant formula, the standard is not strict.
In April 1, 2011 the implementation of new national standard" infant formula for the national food safety standards", only to powdered infant formula of Staphylococcus aureus to make the request, but is still limited in a certain range. Similarly, in suitable for Staphylococcus aureus growth in dairy products," whey powder and whey protein powder of national food safety standards" and" milk powder" in the national food safety standards regulations can limit detection of Staphylococcus aureus. In a similar" cheese the national food safety standards" and" processed cheese" in the national food safety standards, requirements are similar to.
" Dispute between new and old" is a big deal
" Staphylococcus aureus events in China." raise a Babel of criticism of America, but FDA food bureau former deputy director David Acheson ( David Acheson ) is very surprised, he told the Yangcheng Evening News, the crowd 's half, skin and nose are Staphylococcus aureus, in raw meat, eggs, milk products in all natural presence of Staphylococcus aureus.
" We should pay attention to the toxin, but not Staphylococcus aureus." Acheson thinks, the quick-frozen food GB dispute between new and old is a big deal, the United States FDA related standards are strict requirements are not allowed in the presence of toxins. He thinks, food in Staphylococcus aureus usually does not cause disease, due to Staphylococcus aureus growth temperature is 6 - 48 DEG C, produce toxins that temperature is 10 - 45 DEG C, therefore, in the production process of its control in low level, when cooking food as long as the temperature reached 73.9 degrees, can be instant seckill Staphylococcus aureus.
The Chinese Institute of food science and technology director Meng Suhe's view, the big deal of dispute between new and old, led to the frozen food industry crisis, but its backside is industry of our country food trust crisis, how to get the trust of consumers, government and enterprises at present must face the problem.
2011年12月14日星期三
political science
And clean energy difference
Clean energy is not emission energy, including nuclear power station and" renewable energy", renewable energy is the raw material can be regenerated energy, such as hydropower, wind power, solar energy, biomass energy ( biogas ), tidal energy, renewable energy, energy depletion may not exist, so more and more attention in many countries, especially the energy shortage in the country.
Including conventional the clean use of energy, such as coal gasification and liquefaction; renewable energy such as solar energy, wind energy, hydro energy, ocean energy, geothermal energy, biological energy utilization; as well as new energy sources ( such as hydrogen fuel ) the development. Hydrogen fuel calorific value equal to 4 times the weight of carbon, fuel product is water, no pollution to the environment, is an ideal clean energy in the future.
Nuclear energy is clean energy, but the consumption of fuel, not renewable energy, investment is high, and almost all of the country, including the most advanced countries in technology and management, can guarantee the absolute safety of nuclear power station, the former Soviet Union and the United States the Chernobyl accident at Three Mile Island accident impact is very big, Japan also appeared the nuclear leakage nuclear power plant accidents, especially the war or terrorism the main objective of the attack, the attack may have serious consequences, so many developed countries are to build nuclear power plants in Germany, to gradually close all current nuclear power plants, but instead to renewable energy, renewable energy cost than other energy to high.
Renewable energy is the most ideal energy, can not be the effect of energy shortage, but also by natural conditions, such as the need for hydro, wind, solar energy resource, but the most important is the investment and maintenance cost is high, efficiency is low, so the generated electricity of high cost, many scientists now in actively looking to increase the use of renewable energy efficiency methods, with the shortage of resources, renewable energy will play a more and more important role.
The climate change debate
In the past thirty years, the United States of America previous governments on the issue of climate change attitude wavering, the relevant policy changes. During the Carter administration, the United States National Academy of Sciences on climate change human reason and inevitable consequences of making scientific assessment and recommendations for action.
However, in the early nineteen eighties, economic stagnation and conservative circumfluence background, Reagan government environmental regulation as the economic burden, adopted a series of " anti-environment" measures, set off a wave of" environmental protection counter". George H.W. Bush in the White House, in dealing with environmental problems on the continuation of the former government 's guiding ideology, in the mitigation of global warming trend slow, dubbed" the third term of the Reagan administration".
Although the Clinton administration from the beginning to face up to the problem of climate change, and will include the issue of climate change, the environment at the strategic height, to vigorously promote the international climate negotiations, and in 1998 signed the" Kyoto Protocol". However, due to the obstruction of the Republican Congress, the Clinton administration in its two term on the issue of climate change has failed to take meaningful action.
George W. Bush administration at the beginning, in the" political science" by climate warming trend, lack of scientific basis and announced its withdrawal from the" Kyoto Protocol". Although forced the international community more and more accusations and pressure, George W. Bush has issued a" National Energy Policy Act" ( 2005)," energy independence and Security Act" ( 2007), set out to encourage the development of renewable energy and new energy, improve energy efficiency and other content, but during his term of office has no limits on greenhouse gas emissions level.
2011年12月13日星期二
anti-interference
Strong anti-interference capability, no noise accumulation
In the simulation of communication, in order to improve the SNR, required in the signal transmission process in a timely manner to the attenuation of the transmitted signal is amplified, signal transmission in the process will inevitably superimposed noise also are simultaneously amplified.DVB T RECEIVER With the increase of the propagation distance, cumulative noise increasing, in order to cause serious deterioration of transmission quality.
In digital communication, the digital signal amplitude for the finite discrete values (usually from the two amplitude ), in the transmission process while also disturbed by the noise, but when signal-to-noise deterioration to a certain extent, i.e., at appropriate distances using decision method of regeneration, and generates no noise and primary terminal as digital signals, so it can achieve the long distance and high quality of transmission.
For encryption processing
Information transmission security and confidentiality is becoming more and more important, digital communication encryption processing than analog communication much easier, in a voice signal as an example, through the digital signal after conversion can be a simple digital logic encryption, decryption processing.
For storage, processing and exchange
Digital communication signal and computer signal line, is a binary code, which is convenient for the network with computer, is convenient to use the computer to digital signals for storage, processing and exchange, the communication network management, maintenance of automation, intelligent.
The device facilitates integration, miniature
Digital communications using time-division multiplexing, without the need for a larger volume of filter. Equipment most of the circuit is a digital circuit, can be large-scale and ultra large scale integrated circuit, therefore has the advantages of small volume, low power consumption.
Easy to constitute an integrated digital network and integrated services digital network
Using digital transmission mode, can be programmed through the digital switching equipment for digital exchange, in order to realize the transmission and exchange of integrated. In addition, telephone service and various non voice service can be digitized, integrated services digital network.
Clear channel frequency band is wide
An analog telephone band for 4kHz bandwidth, a digital telephone about 64kHz, this is the analog communication still has vitality of the main reason. As the broadband channel ( optical cable, digital microwave ) a large number of use ( a pair of cables can be opened thousands of telephone channels ) as well as the development of digital signal processing technology ( can be a digital telephone digital rate from 64KB / s to 32KB / s compressed even lower code rate ), digital telephone bandwidth problem is not the main problem the.
The above knowable, digital communication has many advantages,DVB-T MPEG 4 so countries are active in the development of digital communication. In recent years, our country digital communication has obtained the rapid development, is moving in high-speed, broadband, intelligent and integrated direction.
In the simulation of communication, in order to improve the SNR, required in the signal transmission process in a timely manner to the attenuation of the transmitted signal is amplified, signal transmission in the process will inevitably superimposed noise also are simultaneously amplified.DVB T RECEIVER With the increase of the propagation distance, cumulative noise increasing, in order to cause serious deterioration of transmission quality.
In digital communication, the digital signal amplitude for the finite discrete values (usually from the two amplitude ), in the transmission process while also disturbed by the noise, but when signal-to-noise deterioration to a certain extent, i.e., at appropriate distances using decision method of regeneration, and generates no noise and primary terminal as digital signals, so it can achieve the long distance and high quality of transmission.
For encryption processing
Information transmission security and confidentiality is becoming more and more important, digital communication encryption processing than analog communication much easier, in a voice signal as an example, through the digital signal after conversion can be a simple digital logic encryption, decryption processing.
For storage, processing and exchange
Digital communication signal and computer signal line, is a binary code, which is convenient for the network with computer, is convenient to use the computer to digital signals for storage, processing and exchange, the communication network management, maintenance of automation, intelligent.
The device facilitates integration, miniature
Digital communications using time-division multiplexing, without the need for a larger volume of filter. Equipment most of the circuit is a digital circuit, can be large-scale and ultra large scale integrated circuit, therefore has the advantages of small volume, low power consumption.
Easy to constitute an integrated digital network and integrated services digital network
Using digital transmission mode, can be programmed through the digital switching equipment for digital exchange, in order to realize the transmission and exchange of integrated. In addition, telephone service and various non voice service can be digitized, integrated services digital network.
Clear channel frequency band is wide
An analog telephone band for 4kHz bandwidth, a digital telephone about 64kHz, this is the analog communication still has vitality of the main reason. As the broadband channel ( optical cable, digital microwave ) a large number of use ( a pair of cables can be opened thousands of telephone channels ) as well as the development of digital signal processing technology ( can be a digital telephone digital rate from 64KB / s to 32KB / s compressed even lower code rate ), digital telephone bandwidth problem is not the main problem the.
The above knowable, digital communication has many advantages,DVB-T MPEG 4 so countries are active in the development of digital communication. In recent years, our country digital communication has obtained the rapid development, is moving in high-speed, broadband, intelligent and integrated direction.
2011年12月12日星期一
electrons
Membrane bilayer heterojunction organic solar cell structure as shown in figure 2. As to the body of the organic semiconductor material absorbs a photon is produced after the hole - electron pair, electrons injected into a receptor organic semiconductor material, electron and hole separation. In this system, the electron donor for P type, N type electron acceptors for holes and electrons, which are separately transmitted to the two electrode,Gaosuibuyou Thailandsolar panels
forming a light current.
And the" Schottky type" compared to battery, the structure is characterized in that the introduction of the charge separation mechanism. Compared with silicon semiconductor, organic molecular interactions between different molecules are much weaker, between LUMO and HOMO and not through a combination of whole body in phase to form a continuous conduction band and valence band.
Carrier in organic semiconductor transmission, through charge in between the different molecular mechanism to realize the" jump", macroscopical performance is its carrier mobility is much lower than the inorganic semiconductor.
At the same time,solar modules
organic small molecule absorbs a photon is aroused, not like silicon semiconductor did in the conduction band and valence band free electrons produced in the left hole.
Optical excitation of small organic molecules, generated by electrostatic interaction is combined together with the hole - electron pair, is commonly referred to as " exciton ( Exciton )". Exciton has limited time, usually at the millisecond level, without complete separation of the electron and hole will compound ( Recombination ), released from their absorption of energy.
Obviously, not separating out free electrons and holes on the exciton, the photocurrent is no contribution. Therefore organic exciton separation efficiency on the photoelectric conversion efficiency of the battery has critical implications.
The Schottky type battery,toner exciton separation efficiency is a problem. Light stimulates the formation of excitons, only in the Schottky junction diffusion layer, rely on section electric field can be separated. Other locations on the formation of excitons, must move to the diffusion layer can be formed on the contribution of light current.
But organic dye in the exciton migration distance is limited, typically less than 10 nm. So most of excitons in the separation into the electron and hole before the compound drop. In organic battery is introduced in the heterojunction results, is obviously the exciton separation efficiency.
Electrons from the excited molecule LUMO energy into electronic receptor LUMO level, this process is essentially exciton separation. The two layer of the organic film at the interface between is not smooth.
In the process of preparation ( thermal evaporation deposition, or solution spin-coating method) the two film layer will form an interpenetrating structure, thereby interface has a larger area. In to the body material phase generated excitons, through diffusion can easily reach the interface of the two materials, the electron injection receptor material LUMO level in order to achieve the separation of charge.
At the same time, many studies showed, receptor material can also absorb corresponding frequency photon exciton, then its HOMO level hole reverse into the donor material HOMO energy level. Therefore, excitons can simultaneously in bilayer membrane formed on both sides of the interface, then through the diffusion in the interface separation. In short, relative to the Schottky type battery, the donor-acceptor double membrane structure can obviously improve the exciton separation efficiency.
forming a light current.
And the" Schottky type" compared to battery, the structure is characterized in that the introduction of the charge separation mechanism. Compared with silicon semiconductor, organic molecular interactions between different molecules are much weaker, between LUMO and HOMO and not through a combination of whole body in phase to form a continuous conduction band and valence band.
Carrier in organic semiconductor transmission, through charge in between the different molecular mechanism to realize the" jump", macroscopical performance is its carrier mobility is much lower than the inorganic semiconductor.
At the same time,solar modules
organic small molecule absorbs a photon is aroused, not like silicon semiconductor did in the conduction band and valence band free electrons produced in the left hole.
Optical excitation of small organic molecules, generated by electrostatic interaction is combined together with the hole - electron pair, is commonly referred to as " exciton ( Exciton )". Exciton has limited time, usually at the millisecond level, without complete separation of the electron and hole will compound ( Recombination ), released from their absorption of energy.
Obviously, not separating out free electrons and holes on the exciton, the photocurrent is no contribution. Therefore organic exciton separation efficiency on the photoelectric conversion efficiency of the battery has critical implications.
The Schottky type battery,toner exciton separation efficiency is a problem. Light stimulates the formation of excitons, only in the Schottky junction diffusion layer, rely on section electric field can be separated. Other locations on the formation of excitons, must move to the diffusion layer can be formed on the contribution of light current.
But organic dye in the exciton migration distance is limited, typically less than 10 nm. So most of excitons in the separation into the electron and hole before the compound drop. In organic battery is introduced in the heterojunction results, is obviously the exciton separation efficiency.
Electrons from the excited molecule LUMO energy into electronic receptor LUMO level, this process is essentially exciton separation. The two layer of the organic film at the interface between is not smooth.
In the process of preparation ( thermal evaporation deposition, or solution spin-coating method) the two film layer will form an interpenetrating structure, thereby interface has a larger area. In to the body material phase generated excitons, through diffusion can easily reach the interface of the two materials, the electron injection receptor material LUMO level in order to achieve the separation of charge.
At the same time, many studies showed, receptor material can also absorb corresponding frequency photon exciton, then its HOMO level hole reverse into the donor material HOMO energy level. Therefore, excitons can simultaneously in bilayer membrane formed on both sides of the interface, then through the diffusion in the interface separation. In short, relative to the Schottky type battery, the donor-acceptor double membrane structure can obviously improve the exciton separation efficiency.
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