Barium(II)-based semiconductive coordination polymers for high-performance direct X-ray detection and imaging: Reducing the exciton binding energy via enhancing π-π interactions

•Two semiconductive Ba(II)-based CPs 1 and 2 with small exciton binding energy (Eb) values were successfully prepared.•The 2-based film detector achieves superior direct X-ray detection performance among CP-based detectors.•The enhanced π-π interactions are beneficial to exciton separation and charge carrier transport irradiated by X-ray.