ساخت دستگاه تبديل نور خورشيد به برق به كمك اسفناج

پژوهشگران موفق به ساخت دستگاهى شده اند كه از اسفناج براى تبديل نور خورشيد به برق استفاده مىكند. شوگوآنگ ژانگ، محقق موسسه فناورى ماساچوست از كلروپلاست هاى اسفناج براى ساختن يك سلول انرژى خورشيدى استفاده كرده است. كلروپلاست ها داخل كلروفيل ها بسته بندى شده اند و كلروفيل ها اجزايى از گياهان هستند كه باعث سبز شدن رنگ برگ ها شده و در عمل فتوسنتز نقش دارند. ژانگ در اين زمينه مىگويد: طبيعت اين پديده را ميلياردها سال است كه انجام مىدهد و اين اولين بارى است كه ما توانسته ايم اين پديده را مهار كنيم. سلول هاى به دست آمده از اين شيوه بسيار ظريفتر و سبكتر از صفحات خورشيدى موجود هستند و مىتوان در نهايت از آنها براى ساخت صفحات كارآمدتر و بانفوذتر استفاده كرد. اين سلول ها تاكنون توانسته اند تنها ۱۲ درصد از نور را به برق تبديل كنند اما ژانگ مىگويد: مى توان با افزايش لايه اى سلول ها بر روى يكديگر نفوذپذيرى و تاثير آنها را به ميزان چشمگيرى تقويت كرد

Popeye uses spinach to power his muscles. Now, scientists are looking to spinach as a power source for supplying electricity
Chemical substances extracted from spinach are among the ingredients needed for making a solar cell that converts light into electricity
Peggy Greb, Agricultural Research Service, U.S. Department of Agriculture
A solar cell converts sunlight into electricity. Most solar cells on the market today are made of a material called silicon. The new device, on the other hand, uses proteins from spinach and from a bacterium named Rhodobacter sphaeroides
To make the solar cell, a team of biologists and chemists from the Massachusetts Institute of Technology extracted certain light-sensitive proteins from spinach and bacteria. They put about 2 billion of these proteins on a piece of glass, making the proteins stick by embedding them in a special framework that looks and acts like a cell membrane
The researchers then put the layer of proteins between layers of other materials called semiconductors, which carry electricity. When the scientists shone certain types of light on the device, the proteins absorbed the light and sent electrons through the semiconductor to an electrode. This activity caused an electric current to flow
–) into a silver electrode."

In this solar cell, light-sensitive proteins obtained from spinach and bacteria (yellow spheres) absorb light and pump electrons (e–) into a silver electrode
Courtesy of Marc Baldo, Massachusetts Institute of Technology
At this early stage in the research, the spinach cell isn't efficient enough to be useful. To improve their solar cell, the researchers want to jam more proteins into a single device. They also want such solar cells to stay active for a long time. One hope is that protein-based solar cells could repair themselves, just like living plants replace their own proteins over time
If it all works out, there may be a new way to harvest the sun's energy. Instead of having to eat your spinach, you might find that the leafy green could someday power your TV set.—E. Sohn

Bahram