Advances in the development of small photoblinking semiconducting polymer dots (Pdots) have attracted great interest for use in super-resolution microscopy. However, multicolor super-resolution imaging using conventional small photoblinking Pdots remains a challenge due to their limited color choice, broad emission spectrum, and heavy spectrum crosstalk. Here, we introduce two types of small photoblinking Pdots with different colors and relatively narrow emission spectra: blue PFO Pdots and carmine PFTBT5 Pdots for blinking-based statistical nanoscopy. Both of these probes feature ultrahigh single-particle brightness, very strong photostability, superior biocompatibility, and robust fluorescence fluctuation. In addition, these small photoblinking Pdots serve as excellent labels for dual-color super-resolution optical fluctuation imaging (SOFI) of specific subcellular structures, indicating their promise for long-term multicolor SOFI nanoscopy with high spatiotemporal resolution.

Generally, crystal field engineering is an important means to regulate Cr3+ luminescence in near-infrared (NIR) phosphors. Host cation substitutions, including single substitutions, double substitutions, and even multiple substitutions, are widely used as a common means to modify the crystal field of Cr3+-activated phosphors. However, the tunable range using this strategy is usually limited because it is susceptible to the limitation of the host and its initial structure. In this work, we designed and synthesized a new type of controllable NIR-emitting phosphor Li2Mg3TiO6:Cr3+ using a new Cr3+ luminescent ion substitution strategy in which a double Cr3+ ion unit [Cr3+–Cr3+] was employed to replace a [Mg2+–Ti4+] unit to balance the charge. Just by changing the concentration of Cr3+, the NIR emission peak of the phosphor can be regularly adjusted from 720 to 920 nm, and the full width at half maximum reaches 258 nm. The internal quantum efficiency and external quantum efficiency of the Li2Mg3TiO6:0.03Cr3+ sample are measured to be 72.1 and 28.1%, respectively. An NIR phosphor-converted light-emitting diode (pc-LED) is fabricated by the LMT:Cr3+ phosphor and a blue chip, and the radiant fluxes of 31.09 mW@(3 V ∼ 100 mA) and 71.56 mW@(3 V ∼ 420 mA) are achieved. The results confirmed that the luminescence material has great application potential in the field of NIR spectroscopy.

Alternating current light-emitting diodes (AC-LEDs) have received significant attention from both academia and industry due to their remarkable benefits of more compact volume, cheaper manufacturing cost, greater energy usage efficiency, and longer service life. One of the most significant challenges for AC-LEDs is the flicker effect, which is mainly caused by the unavoidable 5–20 ms dimming time. Aiming to reduce the flicker effect, we designed a series of excellent blue-light excited cyan-emitting persistent luminescence (PersL) phosphors BaLu2Al2Ga2SiO12:Ce3+, Bi3+ via defect engineering of co-doping Bi3+. Interestingly, we found that co-doping Bi3+ not only effectively enhanced the PersL intensity, but also regulated the PersL lifetime of this phosphors. As the Bi3+ co-doping concentration increases to 0.01, the τ80 value (the time when the PersL intensity decreases to 80% of the initial intensity) increases from 0.24 to 19.61 ms, which proves to be effective in compensating the flicker effect of AC-LEDs. A new method of generating white light emission during the dimming time through adding the blue-light excited cyan PersL phosphor to the original orange-red PersL phosphor was proposed and an AC-LED lamp with a decreased percent flicker of 48.15% was fabricated, which is significantly better than the other currently reported AC-LED devices based on PersL phosphors. These results demonstrate that BaLu2Al2Ga2SiO12:Ce3+, Bi3+ might be an attractive material for low-flicker AC-LEDs.