Recently, Dr. Zhixing Gan and coworkers published their research entitled “The Dominant Energy Transport Pathway in Halide Perovskites: Photon Recycling or Carrier Diffusion?” in the top international journal of Advanced Energy Materials (IF=21.875).
The emerging lead halide perovskites have attracted enormous attention due to their excellent performance in optoelectronic applications, such as solar cells, light emitting devices (LEDs), photodetectors, and lasers. Photon recycling and carrier diffusion are the two plausible processes that primarily affect the carrier dynamics in halide perovskites, and therefore the evaluation of the performance of their photovoltaic and photonic devices. However, it is still challenging to isolate their individual contributions.
In response to this debate, Dr. Gan Zhixing and collaborators designed a series of experiments. First, the Ruddlesden–Popper type perovskite, where interplane carrier diffusion is negligible due to the intercalation with organic spacers, was investigated. Nevertheless, a remarkable photoluminescence redshift still occurs in the vertical direction with increasing thickness, which is generally explained by the photon transport. An ordinary 3D perovskite has been comparatively studied by the depth resolved two-photon spectra. Compared to carrier diffusion, photon recycling is a dominant photophysical process that accounts for the experimental observations and long-distance energy transport in both 2D and 3D halide perovskites. The clarification of this issue will have significant impact on the mechanistic understanding, and future development of photovoltaics, LEDs, and diverse other optoelectronic devices based on perovskites.
This work was highly praised by all four reviewers. They commented that: “The deep understanding on carrier dynamics is indeed of importance for achieving high performance perovskite devices (such as solar cell and LED), so this manuscript may attract broad audiences.” “This is an insightful and very important report, which could help to resolve the debate around the individual contributions of photon recycling and carrier diffusion on the carrier dynamics. The clarification of this issue will have a significant impact on the mechanistic understanding, and future development of optoelectronic devices based on perovskites.”