It is such a hot topic these days. What's the major challenge in this field? Is it really going to be a mainstream technology?
These cells are impressive as they've hit over 16% PCE.
They have good diffusion lengths (mobility and lifetime product) reported to be on the order of 1 micron, and since the material is very absorptive, they can basically absorb everything at their given bandgap (typically around 1.55 eV).
The biggest problem will be stability and lifetime. These materials degrade quite rapidly, even when you scan them taking a JV curve. They also have a tendency to want to try and change phase, so the fabrication conditions are critical and very much an art at this point. That is probably where one of the major challenges will come in.
Perovskite material is under study / experimental stages, Albeit, the preliminary results are very encouraging and one can say, soon it will be the future technology. Perovskite has crystal structure similar to CaTiO2. This structure produces high charge carrier mobilities and longer diffusion lengths, allowing photo-generated EHPs to travel long distance without any energy loss. Consequently, the EHPs can travel through thicker solar cells which can absorb more light than the thin ones.
These cells are impressive as they've hit over 16% PCE.
They have good diffusion lengths (mobility and lifetime product) reported to be on the order of 1 micron, and since the material is very absorptive, they can basically absorb everything at their given bandgap (typically around 1.55 eV).
The biggest problem will be stability and lifetime. These materials degrade quite rapidly, even when you scan them taking a JV curve. They also have a tendency to want to try and change phase, so the fabrication conditions are critical and very much an art at this point. That is probably where one of the major challenges will come in.
Thanks for the answers. The current perovskite materials are also poisonous. Is there any way to over come this challenge?
By the way, I found most of the demonstrated cells are quite small. Why is this? Is there any strategy to solve this problem?
Does anyone know any theoretical work on predicating the efficiency limit of perovskite solar cell?
Dear Jia, the poisonous component of the material, i.e., lead has been successfully replaced by Sn and the devices reporting ~7% PCE will soon be noticed.
There are few announcements from commercial manufacturers who fabricated large area modules of PSCs with PCE ~7%.
Stability of these cells will be a major concern. The perovskite solar cells are even more unstable than organic polymer solar cells. Secondly Lead is poisonous and has to be replaced by some other materials like Tin (Sn), Germanium (Ge), etc.
Regarding the morphology of perovskite layer, it might also be difficult to scale up the device areas in coming days.
Many thanks. Do you expect that mass production can also produce high efficiency exceeding 15%?
The small size of the cells reflects the standards for emerging technology. Besides the research at the moment is focusing on the materials and the working mechanisms, rather than on real devices.
The small size of cells allows to study these system in common lab with the already available equipment.
The upscale of modules is part of the next stage of development, but it requires extra-efforts to optimize not only the material, but every stage of the production and the use of large facility.
Nonetheless many different company and start-ups are working on this task, sometimes "recycling" the DSSC equipments.
About stability I think it is important to highlight the destructive role of humidity in the cell. Cells are in fact stable in vacuum, but they decay rapidly in atmosphere.
Organo metal halide perovskite are the best to date in photovoltaic devices, but why could oxide perovskites not in the same manner?e.g. CaTiO3?
you can read my paper in http://dx.doi.org/10.1063/1.4922150. I also edit wikipedia for perovskite solar cell (physics part).
Pb seems to be the main reason why perovskite is considered toxic. Meanwhile, Sn which has been investigated as a replacement for Pb has only very low efficiencies hence efforts have been directed towards other materials for better improved efficiencies. Overall, the major problem with the perovskite solar cell is its instability and until this problem is solved then perovskite will remain in research labs.
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