Researchers at Nanjing Tech University and other institutes in China have recently created solar cells using 2-D Ruddlesden-Popper (RP) layered perovskites with phase-pure quantum wells (QWs) and a single-well width. These solar cells could achieve remarkable power conversion efficiencies that are largely retained over time.
"We report phase-pure QWs with a single well width by introducing molten salt spacer n-butylamine acetate, instead of the traditional halide spacer n-butylamine iodide," the researchers wrote in their paper. "Due to the strong ionic coordination between n-butylamine acetate and the perovskite framework, a gel of a uniformly distributed intermediate phase can be formed."
This unique design produces phase-pure quantum well films with microscale grains that are vertically aligned. These gains are crystallized at their respective intermediate phases, which could ultimately increase the solar cells' stability.
In a series of initial tests, the researchers found that the solar cells they created achieved a power conversion efficiency of 16.25% and a high open voltage of 1.31V. Moreover, they evaluated the solar cells in three different scenarios: after they were kept in an environment with 65'±'10% humidity for 4,680'hours; after operating at 85'°C for 558 hours; and when they were placed under continuous light illumination for 1,100'hours. In all these three cases, the cells' efficiency decreased by less than 10%.
These results suggest that the limitations associated with the QWs of previously developed RP perovskite-based solar cells could be overcome by introducing a molten salt spacer layer. In the future, the unique solar cell design presented in this recent paper could enable the creation of solar panels or other solar-powered devices that are both efficient and stable.
"Compared to the traditional all-inorganic QWs deposited with vacuum methods, the hybrid organic-inorganic metal-halide perovskite phase-pure QWs offer several improvements, including solution processability, low-temperature fabrication and atomic layer accuracy," the researchers explained in their paper. "Considering the good stability, unique structure and optoelectronic properties, we anticipate that the phase-pure QWs will facilitate the development of solar cells and other perovskite-based optoelectronic devices, such as detectors, light-emitting diodes and lasers."
