Asecondary hydrot hermal process was used to synthesize exotic hollow nanostr uctures of rutile TiO₂ as an electron- transp ort layer for perov skite solarcells.The prepared nano-structu res were used in combin ation with methy lammonium lead iodide e(MAPbI₃)perovskite ,and their photovoltaic proper ties were studied. This core–shell architectu re of aper-ovskite enveloped by TiO₂ provides an enhanced surface area,better contac twith the perovskite because of the larger adsorp tion area,and effective light penetration n. Our results revea led that the hollow nano flowers exhibit aphotocurr ent density of 21.05 mAcm^-2,anopen-circuit voltage of 0.916 V, and afill factorof 0.66, which leads to apower conve rsion efficie ncy of 12.72 %. These result swere also verified by electrochem ical impedan ce spectrosc opy and time-resolv ed photolum inescence spectroscop y. Furthermo re,the effect of the wetting time was studied, and our results revealed that aminimu mtime of 100sis require ed for good penetration nof a MAPbI 3/γ-butyrolacto ne solution .