When these materials get excited with light, electron and holes are generated but it is important for them to hang arround for a while before they recombine so that more photocurrent will be produced. I heard 1microsecond was achieved. Is there any other longer time reported?
Dear Colleagues,
The most important parameter is the diffusion length of mobile charge carriers in the perovskites. A diffusion length of 1 um is a common diffusion length value. This value is very sufficient to satisfy the requirement for the good solar cells which is the diffusion length L must be equal or greater than the the maximum penetration depth of incident solar radiation 1/alpha where alpha is the absorption coefficient.
Fortunately, a thickness of few tenths of a micro meter of the perovskite material is sufficient to absorb the incident solar radiation.
So, here the surface recombination may play a greater role than the volume recombination.
Best wishes
Dear Somaya Abbaspour
The lifetime for electron and holes in perovskite depended on the perovskite structure , where the mixed halide (CH3NH3PbI3xClx )is the logiest one 1069:204 (1069 ± 204) nm for electron and (1213 ± 243 ) nm for hole.
see the like below:
http://onlinelibrary.wiley.com/doi/10.1002/ente.201600486/abstract
For single crystals perovskite lifetimes
http://pubs.acs.org/doi/abs/10.1021/acs.jpclett.7b01922
Dear Maya,
You may need to read these references to better understand.
Good luck.
Article Electron-Hole Diffusion Lengths Exceeding 1 Micrometer in an...
Article Electron-hole diffusion lengths > 175 m in solution-grown CH...
Please read this reference too.
Article Extended carrier lifetimes and diffusion in hybrid perovskit...
Article Efficient Room-Temperature Phosphorescence from Organic-Inor...
Maybe I'm out of point but, I also think that you will be interested in this paper.
This phosphorescent perovskite shows 71 ms in decay time.
Dear Somaya,
welcome,
Perovskite passivation can increase the carrier lifetime by about an order of magnitue to reach appraoch 10 us: https://pubs.acs.org/doi/pdfplus/10.1021/acsenergylett.6b00236
Best wishes
Dear Colleagues,
The most important parameter is the diffusion length of mobile charge carriers in the perovskites. A diffusion length of 1 um is a common diffusion length value. This value is very sufficient to satisfy the requirement for the good solar cells which is the diffusion length L must be equal or greater than the the maximum penetration depth of incident solar radiation 1/alpha where alpha is the absorption coefficient.
Fortunately, a thickness of few tenths of a micro meter of the perovskite material is sufficient to absorb the incident solar radiation.
So, here the surface recombination may play a greater role than the volume recombination.
Best wishes
Dear Somaya ,
The lifetime in single crystals and films is typically different.
A thin film made of halide perovskite has a lifetime of 100 nm up to a microsecond. Meanwhile, single crystals have lifetimes of 15 microseconds up to milliseconds.
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