A real-time and indicator-free sensor specific to nitric oxide (NO) is realized for the first time by integrating a sensing hydrogel film, a top-emitting polymer light-emitting diode (PLED), and a silicon photodetector. The top-emitting PLED is utilized to excite the sensing film specific to NO, and the photoluminescence of the sensing film is transformed into electric signal by the photodetector. The influence of the excitation light on the out-put photocurrent of the photodetector is diminished by two delicately selected organic filters based on their absorption spectra. Lead phthalocyanine is deposited on a top-emitting PLED as a filter for generating an excitation light without overlapping the emission maximum of the sensing hydrogel film. Poly(3-hexylthiophene) is placed in front of the photodetector as another filter to remove the excitation light. This sensor demonstrated a fast photocurrent response to NO with response time within 5 min.