We propose to use a hybrid downconverter system comprising low-cost green perovskite-polymer composite films for liquid crystal display (LCD) backlight unit (BLU) to realize wide color gamut. Recently, ultrastable, highly luminescent CH3NH3PbBr3 (MAPbBr3) organic-inorganic perovskite-polymer composite films have been developed. These films exhibit outstanding color quality with a full-width-at-half-maximum (FWHM) of only 18 nm and a peak wavelength of 530 nm, which makes them promising candidates as green downconverters. Two configurations to hybridize these green films with state-of-the-art red emitting downconverters, including CdSe-based quantum dots (QDs) and narrow peak phosphors, are proposed. Color and efficiency analyses indicate that the hybridization of green perovskite-polymer films with red K2SiF6:Mn4+ (KSF) phosphor could lead to wide color gamut coverage of nearly 90% Rec. 2020 and high total light efficiency (TLE) of around 20 lm/W while maintaining low cost.