It is of intense interest to extend the excellent performance of silicon photodetectors into the infrared spectrum beyond silicon’s bandgap. Detection of infrared radiation is at the base of applications such as night vision, health monitoring, and optical commuincations. Silicon is the workhorse of modern electronics, but its electronic bandgap prevents detection of light at wavlengths longer than ~ 1100 nm. Here we present the photovoltage field effect transitor (PVFET) that uses silicon for charge transport, but adds infrared sensitization via a quantum dot light absorber. Using the photovoltage generated at the silicon:quantum dot heterointerface, combined with the high transconductance provided by the silicon device, we demonstrate high gain (>104 electrons/photon at 1500 nm), fast time response (< 10 s), and widely tunable spectral response. The PVFET shows a responsivity 5 orders of magnitude higher at 1500 nm wavelength than prior IR-sensitized silicon detectors. The sensitization is achieved using a room temperature solution process and does not rely on traditional high temperature epitaxial growth semiconductors, as per germanium and III-V compounds. Our results demonsrate, for the first time, colloidal quantum dots as an efficient platform for silicon based infrared detection, competitive with state-of-the-art epitaxial semiconductors.