A new facile solution method for the synthesis of high-quality CuInSe2 nanocrystals with monodispersed size and uniform hexagonal shape was developed. A high-performance hybrid photodetector based on a hybrid film of CuInSe2 nanocrystals and poly(3-hexylthiophene) was constructed. The device showed distinct "ON" and "OFF" states with a ratio of >100 in photocurrents responding to outside illumination. The high sensitivity and stability of the hybrid device revealed a broad prospect for use of the hybrid material in light detection and signal magnification for the development of large-area, low-cost, lightweight, and foldable products.