Orientation and mobility control of 4HCB organic film for flexible X-ray detectors with high performance

•The space-confined melt process is used to produce highly orientated organic semiconducting crystalline films with a large area.•Confined molecular packing significantly improves the hole mobility.•The 4HCB based X-ray detectors can achieve a high sensitivity with low dark current, result in outstanding direct imaging capabilities.•The device shows steady flexibility, with no degradation in detecting function after 100 cycles of bending.