Xiamen University develops new solar cell

Professor Kang Junyong's research team from the School of Physics and Mechanical and Electrical Engineering of Xiamen University has successfully developed a solar cell using two wide-bandgap semiconductors, zinc oxide and zinc selenide, to greatly stabilize its performance and extend its service life. It is reported that this is the first time in the world that wide-bandgap semiconductors have been used in solar cells.

Recently, the Royal Society of Chemistry's Journal of Materials Chemistry published this result, which attracted wide attention internationally. More than a dozen science and technology websites, including the US Science and Technology Daily, reported and reprinted this result.

According to reports, the so-called wide bandgap semiconductors generally refer to semiconductor materials with a bandgap greater than 2.0 electron volts at room temperature. From a physical point of view, the wider the bandgap, the more stable its physical and chemical properties, the better its radiation resistance, and the longer its service life. But at the same time, the wide bandgap has the defects of less absorption of sunlight and low photoelectric conversion efficiency. Due to this "fatal defect", wide bandgap semiconductor materials were not used as key structures for power generation in solar cells in the past, but only as electrodes.

Improve absorbance and make performance more stable

After in-depth research, the research team found two bottlenecks that restrict "conversion": one is whether photocurrent can be formed; the other is whether the light absorption rate of wide-bandgap semiconductors can be improved. After many experiments, the research team decided to use two wide-bandgap semiconductor materials, zinc oxide and zinc selenide, as materials for solar cells to form a band gap similar to a PN junction, that is, a unidirectional conductive band, so that the current can "flow".

At the same time, the research team significantly reduced the effective band gap of wide-bandgap semiconductors by controlling the conditions, increasing the range of sunlight absorption. At the same time, the stacked film form was changed to a coaxial line form, each of which is only 200 nanometers. The light absorption rate was also improved accordingly.

Wu Zhiming, the main person who completed the project and an associate professor at the School of Physics and Mechanical and Electrical Engineering, said that next, the research team will further improve the battery in terms of resistance, electrodes, etc. to make it reach the optimal state.