For decades, the photodetector market has been shaped by silicon and indium gallium arsenide — materials that work well but demand costly, complex manufacturing and external power to function. A team of Thai researchers at Mahidol University has now proposed a different path: a hybrid perovskite structure, whimsically described as a chocolate-chip-cookie, that combines two materials with different energy thresholds to detect light selectively, efficiently, and without any external power source. The device is not merely a laboratory novelty — it is built using spray-coating and slot-die techniq