Full‐Color and High‐Resolution Femtosecond Laser Patterning of Perovskite Quantum Dots in Polyacrylonitrile Matrix

Laser patterning of perovskite quantum dots (PQDs) in polymer matrix enables in situ synthesis, easy integration, and much improved long‐term stability, holding great promises for varieties of photonics, and optoelectronics applications. Although multi‐color PQD patterns have been demonstrated through tuning the halide stoichiometry, it remains significantly challenging to achieve full‐color patterns due to the slow and spontaneous crystallization of the chlorinated perovskite precursor at room temperature. Herein, polyacrylonitrile (PAN) is introduced to serve as the matrix material, the excess cyano groups of which would coordinate with dissociative cesium and lead cations in the precursor film, leading to the suppression of the unprompted crystallization process. Taking advantage of the nonthermal and contactless ultrafast femtosecond laser, full‐color PQDs are in situ fabricated by tuning the halide stoichiometry in the PAN matrix, with the emission wavelength in the range of 425–685 nm, spanning from deep blue to deep red color, and a sub‐diffraction feature size of ≈400 nm. The approach allows ultrafine and programmable fabrication of full‐color PQD arrays and arbitrary patterns with high resolution and stability. This facile, efficient, and reliable technique believed to offer a novel pathway for precise manufacturing of various photonic or optoelectronic devices based on patterned PQDs. A matrix coordination strategy is developed for femtosecond laser fabrication of full‐color perovskite quantum dots (PQDs) in polymer. The excess cyano groups of polyacrylonitrile coordinate with dissociative cesium and lead cations thus terminating the spontaneous crystallization process of precursor film, leading to full‐color (425–685 nm) and high‐resolution (≈400 nm) PQD arrays and patterns.