Two-dimensional (2D) perovskites are known as one of the most promising luminescent materials due to their structural diversity and outstanding optoelectronic properties. Compared with 3D perovskites, 2D perovskites have natural quantum well structures, large exciton binding energy (Eb) and outstanding thermal stability, which shows great potential in the next-generation displays and solid-state lighting. In this review, the fundamental structure, photophysical and electrical properties of 2D perovskite films were illustrated systematically. Based on the advantages of 2D perovskites, such as special energy funnel process, ultra-fast energy transfer, dense film and low efficiency roll-off, the remarkable achievements of 2D perovskite light-emitting diodes (PeLEDs) are summarized, and exciting challenges of 2D perovskite are also discussed. An outlook on further improving the efficiency of pure-blue PeLEDs, enhancing the operational stability of PeLEDs and reducing the toxicity to push this field forward was also provided. This review provides an overview of the recent developments of 2D perovskite materials and LED applications, and outlining challenges for achieving the high-performance devices."Image missing"
Metal halide materials have recently sparked intense
research because
of their excellent photophysical properties and chemical stability.
For example, RbCdCl3:Sb3+ exhibits broad emission
at about 600 nm with a high photoluminescence quantum yield (PLQY)
over 91% and double emission bands with bright white color. Herein,
we obtained a novel Rb and Cd layered perovskite Rb3Cd2Cl7 doped with Sb3+, which gives luminescence
at 525 nm with a large Stokes shift of 200 nm, originating from a
self-trapped exciton (STE). Its PLQY is 57.47%, but its low-temperature
PLQY becomes much higher at the same wavelength. When Rb3Cd2Cl7:Sb3+ and RbCdCl3:Sb3+ were compared, the two classes of quantum confinement
effects by Rb and Cd ions in the lattice were identified to describe
their electronic states and different optical properties. These results
suggest that properties of Sb-doped cadmium halides could be modified
by the structure type and local atomic confinement to find applications
as promising luminescent materials for optoelectronic devices.
The detection of hepatitis B surface antigen (HBsAg), a coat protein secreted by hepatitis B virus, is a common method for confirming infection in early diagnosis. A new composite of graphene oxide‐ferrocene‐chitosan (GO‐Fc‐CS) was synthesized and used to develop an electrochemical immunosensor with a GO‐Fc‐CS/Au‐nanoparticle layer film for HBsAg detection. The modified layer film exhibited not only enhanced electron conductivity, but also strong reversible redox signal for current changes, excellent biocompatibility, and good film‐forming ability for binding a large number of antibodies. The immunosensor exhibits a wide linear range from 0.05 to 150 ng/mL and detection limit of 0.01 ng/mL for HBsAg. The excellent performance in HBsAg detection suggests that the proposed immunosensor has potential application in clinical diagnosis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.