No abstract

By virtue of their narrow emission bands, near‐unity quantum yield, and low fabrication cost, metal halide perovskites hold great promise in numerous aspects of optoelectronic applications, including solid‐state lighting, lasing, and displays. Despite such promise, the poor temperature tolerance and suboptimal quantum yield of the existing metal halide perovskites in their solid state have severely limited their practical applications. Here, a straightforward heterogeneous interfacial method to develop superior thermotolerant and highly emissive solid‐state metal halide perovskites is reported and their use as long‐lasting high‐temperature and high‐input‐power durable solid‐state light‐emitting diodes is illustrated. It is found that the resultant materials can well maintain their superior quantum efficiency after heating at a temperature over 150 °C for up to 22 h. A white light‐emitting diode (w‐LED) constructed from the metal halide perovskite solid exhibits superior temperature sustainable lifetime over 1100 h. The w‐LED also displays a highly durable high‐power‐driving capability, and its working current can go up to 300 mA. It is believed that such highly thermotolerant metal halide perovskites will unleash the possibility of a wide variety of high‐power and high‐temperature solid‐state lighting, lasing, and display devices that have been limited by existing methods.

Lanthanide (Ln3+)-doped metal halide perovskites with near-infrared (NIR) luminescence have received great attention; however, they suffer from low NIR efficiency, especially for 1.5 μm emission of Er3+ ions. Herein, a Cr3+–Er3+ co-doped Cs2AgInCl6 double perovskite is successfully synthesized using a simple solution precipitation method. Besides a broad-band NIR emission of 4T2 → 4A2 transition of Cr3+ ions centered at 1010 nm, the co-doped sample exhibits an NIR-II emission peak at 1540 nm assigned to the 4I13/2 → 4I15/2 transition of Er3+ ions. Er3+ ions can be sensitized by Cr3+ ions that have broad-band absorption from ultraviolet to NIR region (250–900 nm). Excitingly, through assisted simple post-annealing treatment to eliminate defect states, the Cr3+–Er3+ co-doped sample obtains an unprecedented high NIR photoluminescence quantum yield (PLQY) of 57.5% (Er3+ emission: ∼29.0%), which is the highest value for the Ln3+-doped lead-free perovskites at present. The admirable stability and dual NIR bands of Cr3+–Er3+ co-doped Cs2AgInCl6 pave the way for NIR light sources pumped by multicolor light-emitting diode (LED) chips in potential optical communication, night-vision, and infrared imaging applications.

Near‐infrared (NIR) persistent luminescent nanoparticles (N‐PLNPs) endow a long‐term in vivo imaging with deep tissue penetration and high signal to noise ratio. However, synthesis route and applicable afterglow center for N‐PLNPs are still limited. Here, we report on a new synthesis by employing chemical precipitation as the central pivot, which is simpler and has controllable and reproducible routes than the existing technique. We also introduce Fe3+ ion as a new member to join the group of afterglow emitters. Although its NIR luminescence is ubiquitous, its NIR afterglow is still almost never reported. In this paper, SrAl12O19: Fe3+ N‐PLNPs display a NIR persistent luminescence from 750 to 1000 nm, which is assigned to 4T1(4G)→6A1(6S) transition of Fe3+. Furthermore, a surface‐amination technique is proposed to improve the stability of SrAl12O19: Fe3+ N‐PLNPs in aqueous solution. After encapsulating the N‐PLNPs with 3‐aminopropyl triethoxysilane (APTES), SrAl12O19: Fe3+ @APTES nanocomposites exhibit a hydrophilic stability beyond 20 days in aqueous solution. The results make them valuable in studying the biological functions of biomolecules and monitoring cellular networks in their native contexts.

No abstract