Ultrafast Laser Printing Green–Red Dual‐Phase Perovskite Quantum Dots in Glass

Flexible regulation of local chemistry and band gap of perovskite quantum dots (PeQDs) is crucial for exploring their new functionalities and device applications. In this work, a strategy based on the combination of femtosecond (fs) laser‐irradiation and thermal treatment to effectively manipulate chemical composition and emitting wavelength of PeQDs in amorphous glass, is reported. The engineering of ultrafast laser‐induced thermal effect enables to induce in situ nucleation/growth of dual‐phase PeQDs within an individual glass matrix. By elevating heat‐treatment (HT) temperature, I− ions are driven to surmount the diffusion barrier into the PeQDs lattice, leading to a tunable emission wavelength ranging from 613 to 647 nm. Besides, it is verified that the temperature‐dependent diffusion rate of I− ions plays a pivotal role in affecting luminescent efficiency and color of the dual‐phase glass. Finally, fs laser direct writing of multi‐color patterns is presented, which provides a flexible method to develop new encryption/decryption technology for information security and anti‐counterfeiting. Green and red dual‐phase PeQDs are simultaneously printed in a transparent glass medium via fs laser irradiation. Elevating heat‐treatment temperature can drive more I− ions diffusion from glass matrix into PeQD lattice, leading to tunable emitting wavelength and color. The designed multi‐color patterns are demonstrated to be applicable for high‐level information encryption/decryption.