These exotic crystal semiconductors could lead to efficient solar cells
Scientists from Rutgers University–New Brunswick have found a novel way of controlling light emitted by exotic crystal semiconductors, which could lead to more efficient solar cells and other advances in electronics, according to a study published in the journal Materials.
The study involves crystals called hybrid perovskites, which consist of interlocking organic and inorganic materials, showing great promise in solar cell technologies. The finding may also lead to novel electronic displays, sensors and other devices activated by light and enable increased efficiency at a lower cost in manufacturing optoelectronics, which harness light.
Scientists discovered a new way to control light - photoluminescence - emitted when perovskites are excited by a laser. The intensity of light emitted by a hybrid perovskite crystal can be increased by up to 100 times with a simple voltage adjustment applied to an electrode on the crystal surface.
“To the best of our knowledge, this is the first time that the photoluminescence of a material has been reversibly controlled to such a wide degree with voltage,” said Vitaly Podzorov, a professor in the Department of Physics and Astronomy in the School of Arts and Sciences at Rutgers University–New Brunswick. “Previously, to change the intensity of photoluminescence, you had to change the temperature or apply enormous pressure to a crystal, which was cumbersome and costly. We can do it simply within a small electronic device at room temperature.”
The conductivity of semiconductors like perovskites, with properties that lie between metals with good conductivity and non-conducting insulators, can be tuned in a very wide range, making them indispensable for all modern electronics.
“All the wonderful modern electronic gadgets and technologies we enjoy today, be it a smartphone, a memory stick, powerful telecommunications and the internet, high-resolution cameras or supercomputers, have become possible largely due to the decades of painstaking research in semiconductor physics,” Podzorov said.
Understanding photoluminescence is important for designing devices that control, generate or detect light, including solar cells, LED lights and light sensors. The scientists discovered that defects in crystals reduce the emission of light, and applying voltage restores the intensity of photoluminescence.
Hybrid perovskites are much more efficient, easier and cheaper to make than the standard commercial silicon-based solar cells. The study could help lead to their widespread use, Podzorov opined. An important next step would be to investigate different types of perovskite materials, which may lead to better and more efficient materials in which photoluminescence can be controlled in a wider range of intensities or with smaller voltage, he said.
The study included lead author Hee Taek Yi in Rutgers’ Department of Physics and Astronomy and co-authors Assistant Research Professor Sylvie Rangan and Professor Robert A. Bartynski, department chair. Also, researchers at the University of Minnesota and University of Texas at Dallas contributed to the study.