ABSTRACT
High-resolution patterning of perovskite quantum dots (PQDs) is of significant importance for satisfying various practical applications, including high-resolution displays and image sensing. However, due to the limitation of the instability of PQDs, the existing patterning strategy always involves chemical reagent treatment or mask contact that is not suitable for PQDs. Therefore, it is still a challenge to fabricate high-resolution full-color PQD arrays. Here, we present a femtosecond laser-induced forward transfer (FsLIFT) technology, which enables the programmable fabrication of high-resolution full-color PQD arrays and arbitrary micropatterns. The FsLIFT process integrates transfer, deposition, patterning, and alignment in one step without involving a mask and chemical reagent treatment, guaranteeing the preservation of the photophysical properties of PQDs. A full-color PQD array with a high resolution of 2 µm has been successfully achieved. We anticipate that our facile and flexible FsLIFT technology can facilitate the development of diverse practical applications based on patterned PQDs.
ABSTRACT
Organic semiconductor single crystal materials have broad application prospects in the field of high-performance optoelectronic devices because of their highly ordered structure, few defects, and high carrier mobility. However, it is difficult to control the nucleation location of crystal formation in the current commonly used crystal growth methods including physical vapor transport and solution processing, which makes it difficult to manufacture organic crystal devices. Laser-induced crystallization technology is expected to solve this problem. In this study, we demonstrated nucleation in situ of a perylene crystal by femtosecond laser induced cavitation. The results show that the crystallization of perylene crystals induced by the femtosecond laser is mainly due to the aggregation effect by laser cavitation bubbles caused by multiphoton absorption. This strategy facilitates the application of organic single crystals to optoelectronic devices.
ABSTRACT
Colloidal quantum dots (QDs) have exhibited great potential for optoelectronic applications, including displays, lasers, anti-counterfeiting and information storage. However, the high-resolution patterning technique of QDs is still a challenge, while precise patterned QDs are of great value for practical applications. Here, a femtosecond laser direct writing strategy was demonstrated for the in situ fabrication of high-resolution-patterned perovskite quantum dots (PQDs) by the laser-induced Marangoni flow to aggregate and deposit the PQDs based on the opto-thermoelectric mechanism. By regulating the laser power and the exposure time, the minimum line width could reach 1.58 µm. Importantly, through the patterning of red, green and blue PQDs, the strategy exhibited the applicability in full-color PQD materials. Moreover, the deposited PQDs can preserve the original photophysical properties including photoluminescence spectra and excited state lifetime. The approach provides a strategy to fabricate high-resolution patterned PQDs in situ, which is a promising alternative in photonic applications including high-resolution displays and anti-counterfeiting.
ABSTRACT
This study was performed to culture and preliminarily identify the primordial germ cells (PGCs) isolated from the genital ridge of the Mongolian sheep fetus. The growth characteristics of the sheep PGCs were detected in different culture systems such as culture media, resources, and state and passages of feeder cells. The obtained embryonic germ (EG) cells were identified by morphology, enzymology, and immunofluorescence. The results showed that the sheep EG cell colonies were ridgy, typically nest like, and compact, and had regular edges. Alkaline phosphatase staining reaction was weakly positive. EG cells expressed Kit, Rex-1, Nanog, and Oct-4. Immunofluorescence detection was weakly positive for Oct3/4, whereas positive for SSEA-1, SSEA-3, SSEA-4, TRA-1-61, and TRA-1-80.