Scientists find the biggest shortcoming of photovoltaic panels: defects in the hybrid perovskite lattice
Hydrogen vacancies in the methylammonium molecule (center The black dot to the left)
Hybrid perovskite has excellent photovoltaic performance, and many people expect it to promote the further development of solar energy technology. The so-called “hybrid”, the envoy inserts organic molecules into the perovskite lattice as an inorganic substance to maintain a structure similar to the perovskite mineral.
The photovoltaic conversion efficiency of this type of material is comparable to that of silicon-based solutions, but the production cost is much lower. Unfortunately, the currently known perovskite lattice defects will cause the photovoltaic efficiency to dissipate in the form of heat.
For many years, a large number of researchers have been in-depth Understand this flaw. A research team led by Professor Chris Van de Walle of the UCSB Department of Materials has just made an important discovery.
Project lead researcher Xie Zhang said: “Methylammonium lead iodide is a typical mixed perovskite, but it is also very easy to break one of the bonds and remove the hydrogen atom from the methylammonium molecule. “.
Research Picture-2: Exist in MAPbI3 Hydrogen vacancies
Hydrogen vacancies will turn into charge absorbers, and these charges are generated by photons falling on the photovoltaic panel and move in the lattice. In this case, the idle charge will not be able to continue effective work (such as charging the battery or powering the motor), thereby reducing efficiency.
It is reported that this research was aided by advanced computing technology developed by Van de Walle’s team, which provided detailed information about the quantum mechanical behavior of electrons in materials.
Research Picture-3: MAPbI3 Hydrogen Vacancy Non-radiative capture
Mark Turiansky, a senior graduate student of the Van de Walle research team involved in the research, helped him establish a complex method that can convert this information into a quantitative charge carrier capture rate value.
Turiansky said: “Our team has built a strong method to determine which processes will lead to a reduction in efficiency, and it is great to see that this program provides such valuable insights for an important financial resource. “.
Research Picture-4: FAPbI3 Hydrogen Vacancy And its induced non-radiation recombination
Through repeated experiments, we found that replacing methylammonium molecules with Formidinium can make perovskites show better performance. Looking to the future, scientists are expected to develop new materials with higher performance, more reasonable costs, and more outstanding environmental benefits.