The development of perovskite nanocrystals (NCs) based light-emitting diodes (LEDs) are looking for new patterning technology, which is crucial for realization of high resolution and full color displays. Herein, femtosecond (fs) laser processing is introduced for fabrication of patterned and pixelated CsPbBr₃ and CsPbI₃ NCs films. The rapid removal of NCs in target area under fs laser radiation is demonstrated, proving the effectiveness of fs laser ablation for patterning of perovskite NCs. As a result, pixelated CsPbI₃ and CsPbBr₃ NCs films with pixels per inch (PPI) up to 1693 and clear boundaries are successfully obtained. Then, electroluminescent (EL) devices with bilayered emission layers (CsPbBr₃ and CsPbI₃ NCs) are fabricated for exploration of multicolor LEDs. Through understanding into the carrier recombination dynamics, the dominant red emissions in these EL devices are well explained. Finally, multicolor EL devices with green and red pixels are realized with one-step fs laser ablation on CsPbI₃ NCs because of their priority in carrier recombination. Moreover, the as-fabricated multicolor EL devices achieve a maximum luminance of 488 cd/m² and external quantum efficiency of 7.7%, demonstrating great potential of fs laser ablation towards pixelated full color perovskite NCs based LEDs.

Flexible optical sensing systems have evolved into a promising frontier for personalized health monitoring, leveraging their non-invasive operation and continuous data acquisition. Nevertheless, current optical solutions remain constrained by limitations in detection sensitivity and specificity, hindering their reliability in dynamic clinical environments. Herein, we propose a design of flexible semi-interpenetrating network hydrogel lasing textiles for multifunctional sensing, including relative humidity and acid pH detection. By integrating the humidity-responsive swelling and carboxyl protonation-mediated optical loss modulation of hydrogels with whispering-gallery-mode microcavity lasers, we achieve a dual-parameter flexible optical sensing based on wavelength shift and spectral linewidth modulation, enabling a 227 pm/% RH sensitivity of humidity detection and 125 pm/pH sensitivity of acid pH monitoring, with limit of detection of 0.71% RH and 0.55 pH, respectively. This work is expected to establish new pathways for non-invasive health monitoring in flexible systems.

Lasing emissions with multiple and tunable modes are promising in coding field as a novel cryptographic primitive. With the advantages of simple fabrication, full-color and high-quality-factor whispering gallery mode lasing inside a circular cross-section, polymer microfibers are attractive for photonic devices. However, polymer lasing microfibers for information encryption have never been reported. Herein, we propose a design of printable lasing microfiber encryption chip by in-situ tuning the effective refractive index of the microresonator arrays via a facile approach. Through inkjet printing high-refractive-index nanoparticles on the designated position of lasing microfiber arrays, the effective refractive index of the microcavities is regulated, and the ratio of wavenumber spacing between transverse electric and transverse magnetic mode to the free spectral range can be modulated, particularly with neglectable influence by the size factor. Thus, the programmable region selective encoding process can be conducted simply by a printing program within several minutes. Besides, the encoded microfiber arrays are encapsulated into polydimethylsiloxane to reduce the scattering loss and environmental interference, and a printable encryption chip is realized. This work is expected to provide a platform for the printable encrypted devices.