p-i-n heterostructured quantum-dot electroluminescence (QD-EL) device was fabricated by soft-chemical process, which shows a low turn-on voltage comparable to OLEDs. To construct the multilayered device structure, p-type polymer semiconductor was deposited on the ITO glass by sequential process of coating and thermal curing, thereupon a few monolayers of QD was spin-coated. n-type metal-oxide film was deposited on top of the QD luminescence layer by sol-gel method, providing a facile and low-cost route for the ETL fabrication. Prior to solution-processed ETL construction, a post-treatment is performed using cross-linking agent, in order to chemically-immobilize the QDs. As a cathodic electrode, relatively air-stable aluminum was deposited. The constituent material as well as the electronic band structure of the integrated device guarantees operating stability in air and low turn-on voltage.