Study On Improving Performance And Stability Of Perovskitesolar Cells By 9-（4-Methoxyphenyl）-10-Tosylphen-Anthrene

Perovskite solar cells（PSCs）have received considerable concern owing to the high power conversion efficiencies（PCEs）and low fabrication cost.With vast development over the past decade,the record PCE of PSCs has rapidly climbed to a certified PCE of 25.7%from the initial 3.8%,which can be attributed to two major factors.The first one should be attributed to the excellent intrinsic properties of perovskite materials,including direct and tunable bandgap,large light absorption coefficient,balanced electron-hole transport,and long carrier lifetimes,etc.The other one is owing to continuous innovations in perovskite film fabrication technologies and device engineering.Regardless of the current high PCE record,there remains significant space for further improvement for PSCs to approach their Shockley-Queisser limit.This can be due to the existence of various imperfections in PSCs,including but not limited to intrinsic defects of perovskite materials,energy-level mismatches at key device interfaces,and high interfacial contact resistance.Therefore,the field has been devoting continuous efforts to searching for strategies to suppress/reduce defects,amongst which the use of additive engineering is one of the most effective strategies.The chemical doping method is a common method to fabricate high-performance devices.To modulate the crystallization of perovskite films and suppress/reduce defects,an organic small organic molecule,MPTP,was synthesized and introduced into perovskite precursor to prepare films.The optimal condition of FA_0.9Cs_0.07MA_0.03Pb(I_0.92Br_0.08)₃system was determined by a series of screening conditions:at annealing temperature of 100℃,high quality perovskite films were prepared by using DMSO and DMF as precursors（v/v,4/1）,FTO as glass substrate,EA as reverse solvent and PTABr as passivation layer.After that,MPTP was doped into two different systems of FA_0.9Cs_0.07MA_0.03Pb(I_0.92Br_0.08)₃and(FA_0.95Cs_0.05Pb I₃)_0.975（MAPb Br₃）_0.025.The optimal concentration of MPTP was found to be 0.5 mg·m L^-1through the concentration screening of the additive.MPTP as an additive can effectively passivate FA_0.9Cs_0.07MA_0.03Pb(I_0.92Br_0.08)₃perovskite defect,and improve the energy conversion efficiency of the device from 20.90%to 23.04%.Happily,MPTP additive can also passivate the(FA_0.95Cs_0.05Pb I₃)_0.975（MAPb Br₃）_0.025defect,further improving the energy conversion efficiency of the device from 20.22%to 22.11%.The intermolecular interactions between MPTP and perovskite were revealed by varieties of characterization techniques（Fourier transform infrared spectroscopy,nuclear magnetic resonance,X-ray photoelectron spectroscopy,etc.）,which were also supported by density functional theory simulation.With the introduction of MPTP,larger grains and reduced defects of perovskite films were obtained,along with lessened non-radiative recombination and enhanced hole extraction in resultant devices.The MPTP-treated devices exhibited significantly improved efficiency and stability.