The past two years have seen the uniquely rapid emergence of a new class of solar cell based on organic-inorganic halide perovskite. Although less explored than its tri-iodide counterparts, CH3NH3PbBr3 has a larger bandgap of 2.3 eV with a higher voltage potential that is suitable for tandem solar cell applications. In this paper, we report a vapor-assisted method for depositing and fully crystallizing CH3NH3PbBr3 film on mesoporous TiO2 with good coverage. CH3 NH3PbBr3 fabricated using this method has demonstrated long carrier diffusion length (>1 μm) as estimated by transient photoluminescence-quenching measurements. We demonstrate solar cells fabricated using such films and spiro-OMeTAD as the hole transport layer with an averaged (from forward and reverse scans) conversion efficiency of 8.7%, Voc of 1.45 V, Jsc of 9.75 mA/cm2, and fill factor of 61.5%.