Ultraviolet Light Absorbing Materials

Around 100 years. time ago, there was someone chemist who by the way has no intention of watching the bizarre events that lead him on an amazing discovery. This British guy has a dog who was sick stomach. The dog was given drugs that contain quinine bisulfate substances. The dog then playing around near a container filled with chemicals I2 (iodine). Then, in a way it does not intend dog urinating on the iodine. Suddenly iodine which has been attacked by the sulfuric switch colors so green crystals. British scientists were also soon learned interests and crystals. Finally, he found that the crystals that can block light waves! However, what this discovery means? At that time no one has guessed that this discovery is later will affect the industry as well as technology, especially technology related to glass and plastic industry.

Most twenty years. after the incident, Edwin Land (inventor of the Polaroid camera) successfully applying the composition of this invention as well as the spectacle lens. Eyeglass lenses that can absorb light up the eyes of the user regardless of the damage caused by ultraviolet waves from sunlight. This spectacle lenses including suspended particle device (SPD) have tabled because that contain particles similar green crystals before. In fact changes in SPD technology is not just limited to the spectacle lens. Currently windows and glass in buildings and building houses also began coated particles inhibitors of these rays.

Window tomorrow can set the total incoming light is composed of most of the composition of the particles that wraps the light barrier earlier. Particles that exist in the deepest arrangement. To be able to move freely, the particles were mixed in a fluid suspension or liquid to make the film. This arrangement is covered by the arrangement of the glass (glass) or plastic material that has been covered with a transparent conductor. When no power is delivered by the conductor material, the particles in the film immediately made ​​a straight line (not to be random) to light waves can go through glass and look clear (transparent). When others may be reduced, these particles begin to create an irregular pattern that has a gap that can be passed to the smaller rays. When it takes place, the window looks a little bit darker. When others may always be reduced to achieve 0 (power flow is stopped), the glass window will appear black and dark because there is no longer a gap that can be passed rays.

To set the total electricity flowing, the SPD is equipped with a control device in two types: automatic and manual. Automatic control device which is generally put on some cells are so sensitive to light (photocell) to automatically switch the turn of the beam intensity as time goes on. Control device operated by hand generally in the form of a remote control or rheostat. SPD technology has been widely applied to various products that many of us use daily (except glasses and glass window), as well as a roof made of glass as well as on the monitor computer monitor.

With the exception of SPD technology, there are many other alternatives to make the window tomorrow. Alternatives The most promising technology is liquid crystal (liquid crystal) and electrochromic technology.

Liquid crystal technology has been widely used around us. From start to monitor a calculator, a stopwatch, a timer on the microwave oven, digital clock, tv, computer to monitor. Altogether equipment that uses liquid crystal monitor his performance. Liquid crystal display or also known as LCD also uses electricity to change shape to the melting of crystals can create the appearance of numbers and letters on the monitor. The same technique is applied to the glass window. Liquid crystals are used for window glass was dispersed in the polymer material technology is meant to polymer dispersed liquid crystal (PDLC).

Time to electricity liquid crystal, the molecules immediately lined up to create a parallel beam arrangement can be through (a similar principle to the SPD technology). In these circumstances the windows appear transparent. At the time of electricity will not flow, the liquid crystal molecules is back at the beginning has the form (random) to light can not penetrate. In the glass window using PDLC is no situation in (ie there are a few rays can get through another time electricity may be reduced) as the SPD. PDLC technology has been widely used in the glass windows in office buildings and homes.

There is one of the most major flaws SPD and PDLC. To maintain a state of transparent glass, the 2nd of this technology requires a flow of electricity in a way constantly. When electricity is stopped, the glass immediately so dark. This sort of thing makes it very ineffective in terms of power consumption. Electrochromic technology (electrochromic window) is to offer an alternative solution of this problem. In electrochromic windows, power flow even make glass appear dark (the inverse of the SPD and PDLC). Electricity used by others may only require a low (low voltage).

The composition of the outermost is the arrangement of the glass itself (can also be made ​​of plastic material), which acts also as protective layers in it. 2nd arrangement that fits under the glass composition is the composition of the oxide transparent (clear) and shaped conductors. The third arrangement is an arrangement in the form of the electrochromic material, usually used the tungsten oxide (WO3). The composition of the four is the electrolyte material (ion conductor materials), as well as to the arrangement of the five is a gathering place for the composition called ions. These layers were then closed again by the oxide composition and arrangement of the same glass with the composition of the 2nd and last initial arrangement to form layers like a sandwich (sandwich). All seven of this arrangement can forget wave visible light (transparent) no time given voltage.

There are other possible low (no electrons flow from the negative pole of the voltage source to the positive pole) in the 2nd arrangement which wraps three oxides in the composition resulted in the transfer of positively charged ions or anions (A +) to the electrochromic composition. This positive ion is an anion can be hydrogen or lithium. Anion driven through the electrolyte composition to be up to the electrochromic composition. There electrochromic anions in this arrangement resulted in the change of the characteristics of the optical and thermal character of the material to absorb visible light waves.

Solar heat wave that followed the visible light is also absorbed by this electrochromic material. Because of its light waves are absorbed, so the windows were dark (opaque). By the time the electricity is stopped, the anion is in electrochromic composition was again pushed out through the electrolyte and ion back to the storage place (where it started). Because the electrochromic composition will not contain anion, characteristic optisnya back to the very beginning until the glass back so transparent.

Like the SPD, the intensity of the light can go through this electrochromic windows can be arranged until we can get the state of the corresponding input of sunlight at what we desired (Figure 1). This is not just a clever window gave us the control to adjust the intensity of light in the space, but also give us relief to set the room temperature by changing the state of the thermal character elektrokromiknya arrangement. With this technology, we can reduce spending for a variety of other electronic equipment or space cooling type air conditioner (AC). Power efficiency is the main advantage of this window of tomorrow.