We demonstrate that double spin coating, where a perovskite film is covered with another perovskite film, can increase substrate coverage from 81% to 97% along with an increase of film thickness from 151 +/- 17 to 246 +/- 18 nm. The increased substrate coverage by double coating improves the solar power conversion efficiency from 7.1 +/- 0.6 to 10.3 +/- 1.0%, an approximate 1.5-fold increase. Additionally, a double-coated film of higher substrate coverage exhibits amplified spontaneous emission (ASE) while a single-coated film of lower substrate coverage does not exhibit ASE. Double coating is an attractive method for increasing substrate coverage and improving solar power conversion and ASE. (C) 2016 Elsevier B.V. All rights reserved.