hi, Please refer to the thickness range of different layers of provskite solar cells such as P3HT, PCBM, MAPbI3, etc. The factors that have the greatest impact on the cell's efficiency, if there is any new information available to me.
sincerely yours
vaezzadeh
For getting a higher efficiency device, you need to optimize the thicknesses of all layers , but there is thickness range where you can play. The active layer (P3HT-PCBM) thickness usually be in range 400nm-800nm. but if you are using P3HT as hole transport layer and PCBM as electron transport layer, then P3HT and PCBM have thickness in the range of 20-50 nm. The lead hallide layer thickness should be in the range 600 nm. Read the attached articles for more detailed procedure and effect of layer thickness on final device efficiency.
The major material is the active absorber layer which is the perovskite material. This material has a diffusion length of about 1 um and it is more or less intrinsic meaning the the photogenerated electron hole pairs will be separated and collected by the electric field built in this region. If the drift velocity is small then the electron hole pairs can recombine in their way the anode and cathode.
So, the thickness of this layer is subjected to the following constraints:
- It must be thick enough to absorb the longest possible wave of the incident radiation meaning that d>= 1/alpha , with alpha is the absorption coefficient of the longest absorbed wavelength
- d must be smaller than the diffusion length,
- d must be small enough such that the electric field in the i- perovskite region is sufficient to collect generated electron hole pairs before they recombine at the open circuit voltage.
d in the order of about one micrometer,
The HTL layer if organic must be thin and have high hole concentration because the organic material has low mobility. Tens of nanometers is the proper thickness of the HTL to reduce the series resistance. The same applies for the electron transport layer it must have high electron concentration with thickness of manometers. Also if they are in the path of the radiation they must be also transparent and thin. So, 10 of nanometers are the suitable lengths for these layers. Chandra brought many papers containing information about the thickness of the different layers.
Best wishes
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