The development of new chemical methods to prepare large area perovskite thin film solar cells is desirable for potential future industrial applications. In this paper, a novel fabrication of perovskite CH3NH3PbI3 thin films based on direct metal surface elemental reaction (DMSER) method in an ambient atmosphere is discussed. The as-prepared CH3NH3PbI3 thin films are highly pure and crystalline. Consequent Transient photovoltaic (TPV) tests were conducted and show that these thin films have a long minority carrier lifetime as good as the perovskite thin films obtained via common two-step method from the literature. Although there have been many studies that have developed perovskite solar cells (PSCs) during the past five years, the current study is the first report using elemental Pb as a precursor to fabricate perovskite solar cells, which were found to be relatively stable upon storage without encapsulation in glove box for more than 200 days. This Pb-initiated in-situ reaction allows for the fabrication of large area and uniform perovskite thin films. For example, in our preliminary studies, we have fabricated large area solar cell device samples (1.10 +/- 0.05 cm(2)) and have evaluated their photovoltaic performance under standard conditions (AM 1.5, 100 mW cm(-2)). (C) 2016 Elsevier B.V. All rights reserved.