Natural Vein Graphite is found in abundant in India and Sri Lanka. Use of high purity natural vein graphite in multi layer solar cell to make it cost effective is one of the main objectives. Another objectives include use of spin coater and RF sputtering plasma as the fabricating equipment for growing multilayer polycrystalline solar cell (PSC) having good reproducibility and better energy conversion efficiency
Experimental
Fabrication of multilayer solar cells [1-3] has been done by spin coater technique. Spin coating and RF sputtering techniques have been used to tailor the final product. Improved CH3NH3PbX3 i.e. MAPbX3 perovskite having dopant P3HT was prepared by sol-gel technique, later on, the improved MAPbX3 was spin-coated at a high speed of rotation in the range of 3000 rpm. Compact TiO2 and mesoporousTiO2 coatings on ITO (Indium Tin oxide coated glass substrate) have been carried out by RF sputtering. Tin oxide coating on a glass sub-state was done by spin coating. For comparison, commercially available F-doped ITO glass substrates have also been used. Graphene oxide solutions have been made by sol-gel technique and the coating was done by spin coating. The graphene oxide solution has been produced using high purity natural vein graphite. Spiro-OMeTAD having formula 2,2′,7,7′-Tetrakis[N, N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene was deposited by spin coating at high speed to grow a homogeneous film having a better interface.
Result
A better-improved perovskite solar cell has been fabricated by spin coating technique. Studies have been done for the optical band gap, carrier diffusion length, hysteresis, and the charge carrier density of the perovskite solar cell. The optical band gap of the solar film was obtained as 1.9 eV. Electron mobility of the cell was found as 1,213 cm2/Vs and the hole mobility was observed as 426.7 cm2/Vs . J-V curve of PSC has shown almost stable and low hysteresis, It confirms fabrication of a stable perovskite solar cell. Charge carrier density was obtained as 9 x 1015 cm-3 . It has been observed that the power conversion efficiency of this solar cell is around 25%.
Conclusion
Due to the low-cost mineral used for making the Graphine oxide the final cost of fabrication of solar cell is cost-effective in comparison to other methods. At the same time due to the use of spin coater and RF sputtering machine, this method is found to have better reproducibility in comparison to other methods so far developed. Therefore, the outcome of this research work can be said as the fabrication of a cost-effective polycrystalline Solar cell (PSC) with a higher degree of reproducibility and energy conversion efficiency.
References
[1] A review of perovskite solar cell stability, R.Wang et.al, Adv. Funct. Mater (2019)1808843(1-25)
[2] Factors affecting the stability of perovskite solar cell- comparative review,U.Krishnan et.al.,Jr of photonics for energy,( 9/2)(April-June 2019)21001(1-42)
[3] A mesoporous-planar hybrid structure, R.K.Mishra et.al. Jr of Materials Che. A, DOI: 10.1039/c6ta06960f