Improving Performance Of Mesoporous Perovskite Solar Cells Via BCF As A P-type Dopant

In recent years,perovskite solar cells have attracted considerable interest due to their low cost,simple production process,relatively high photoelectric conversion efficiency,adjustable bandgap and bendable advantage.Hole transport layer,which is in charge of energy level matching and hole transport,is an very important part of the device structure.However,most efficient perovskite solar cells are based on organic hole transport layer which takes up a large portion of the cost of perovskit solar cells.The poor conductivity of intrinsic organic semiconductor is the other problems and p type dopants are needed in practice,which hinder the large scale application of perovskite solar cells.First,a well-soluble tris(pentafluorophenyl)borane(BCF)was introduced into spiro-OMe TAD as a p-dopant.The conductivity of spiro-OMe TAD films was dramatically enhanced.Nearly double increase in power conversion efficiency(PCE)was obtained compared with the PSCs based on pristine spiro-OMe TAD HTL.By the introduction of Li-TFSI and TBP into the BCF-doped spiro-OMe TAD film,the conductivity of spiro-OMe TAD film could be further enhanced.The working mechanism of the BCF doping effect on spiro-OMe TAD was detailed studied.BCF had a significant solubility than commercial FK209,which resulted in a better morphology and a higher conductivity for BCF-doped spiro-OMeTAD film.It was found that the device average efficiency and the reproducibility of BCF-based PSCs were better than the ones of FK209-based PSCs.The optimum PCE of perovskite solar cells was up to 14.65 %.Secondly,perovskite solar cells with double hole transport layers were fabricated with the spin-coating process.The double hole transport layers combined the high hole mobility of Cu SCN with the good film forming properties of PTAA.What's more,it solved the corrosive problem of Cu SCN solution to perovskite film.By optimizing the thickness of Cu SCN and the doping concentration of BCF into PTAA,the performance of the perovskite solar cells was achieved to 11.77 %.