An electronic device, such as a thin-film transistor, includes a substrate and a dielectric layer formed from a dielectric composition. The dielectric composition includes a dielectric material, a crosslinking agent, and a thermal acid generator. In particular embodiments, the dielectric material comprises a lower-k dielectric material and a higher-k dielectric material. When deposited, the lower-k dielectric material and the higher-k dielectric material form separate phases. The thermal acid generator allows the dielectric layer to be cured at relatively lower temperatures and/or shorter time periods, permitting the selection of lower-cost substrate materials that would otherwise be deformed by the curing of the dielectric layer.