An X-ray detector has a layered structure that includes a substrate, a TFT array disposed on the substrate, a photodiode layer disposed on the TFT array, and a scintillator layer disposed on the photodiode layer. The scintillator layer comprises a particle-in-binder composite that contains a continuous parylene matrix having dispersed therein a plurality of particles that include a scintillator material that emits light in response to the absorption of X-rays.