An image sensor with an array of image sensor pixels is provided. Each image pixel may include a photodiode and associated pixel circuits formed in a semiconductor substrate. Buried light shielding structures may be formed on the substrate to prevent pixel circuitry that is formed in the substrate between two adjacent photodiodes from being exposed to incoming light. The buried light shielding structures may be lined with absorptive antireflective coating material to prevent light from being reflected off the surface of the buried light shielding structures. Forming buried light shielding structures with absorptive antireflective coating material can help reduce optical pixel crosstalk and enhance global shutter efficiency.