Day-Night imaging technology that obtains full-color and infrared images has great market demands for security monitoring and autonomous driving. The current mainstream solution relies on wide-spectrum silicon photodetectors combined with Infrared Cutfilter Removal, which increases complexity and failure rate. Here, we address these challenges by employing a perovskite photodetector based on Pb-Sn alloyed single crystal with a vertical bandgap-graded structure that presents variable-spectrum responses at different biases and extends the infrared detection range close to 1100  nm. In addition, the optoelectronic characteristics feature long-term operational stability over a year.