Investigation On Mesoscopic P-I-N Structure Perovskite Solar Cell

Due to the qualities of stable, easy to preparing, lower cost and huge potential in promoting the power conversion efficiency(PCE), hole-conductor-free organometallic perovskite solar cells(PSC) with P-N heterojunction based on carbon counter electrode have become the focus of its' area. Since NiO had used as electron blocking material and hole conducting material in heterojunction PSC. In this article, on basis of TiO2/Al2O3/carbon structure devices, we fabricated a whole new P-I-N triple-layer mesoscopic PSC in which a P-type NiO layer was inserted between insulating Al2O3 layer and carbon electrode, thus we could further improve the cells' PCE.All the films of our devices mentioned in this paper were prepared by screen-printing technology, the perovsike light absorber formed instantly inside pores of the entire triple-layer structure upon sequential deposition of PbI2 and CH3NH3 I. In the thesis, firstly we narrated a series of optimizing experiments over a simpler device structure TiO2/Al2O3/carbon, then we fabricated new P-I-N structure PSC with NiO layer in it until the simpler ones with only insulating Al2O3 layer achieved a stable PCE. After that, a further study on the interfacial carriers transfer and charge recombination processes were carried out with photocurrent/photovoltage, incident photon to current conversion efficiency, dark current, photoluminescence, impedance spectroscopy measurements.It turned out, compared with TiO2/Al2O3/carbon structure PSC, P-I-N structure PSC presented better I-V characteristic parameters, a considerably high PCE up to 13.7% was achieved. Meanwhile the measurements mentioned above helped reveal that NiO layer in P-I-N structure devices reinforced the charge transfer process at the perovskite/carbon interface and weaken the process of charge recombination in the system. Besides, the P-I-N structure PSC had exhibited good stability over 1000 h in air in the dark.