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Inkjet printing is a powerful technology for realizing high‐density pixelated perovskite light‐emitting diodes (PeLEDs). However, the coffee‐stain effect in the inkjet printing process often leads to uneven thickness and poor crystallization of printed perovskite features, which deteriorates the performance of PeLEDs. Here, a strategy is developed to suppress the coffee‐stain effect via enhancing Marangoni flow strength. An interfacial poly(vinylpyrrolidone) (PVP) layer is incorporated to tune the surface tension of the underlying hole transport layer (HTL) and enhance the perovskite crystallization. The substrate temperature is also carefully controlled to tune the printing solvent evaporation rate rationally. By optimizing the thickness of the PVP layer and the temperature of the printing stage, the coffee‐stain effect is dramatically restrained. In addition, the interfacial insulating PVP layers play a positive role in suppressing leakage current level of PeLEDs by avoiding any direct electrical contact between HTL and electron transporting layer. Finally, an inkjet‐printed PeLED with a brightness of 3640 cd m–2 and external quantum efficiency of 9.0% is achieved. This work highlights the availability of inkjet‐printing technology for fabricating patterned PeLEDs in information display applications. [ABSTRACT FROM AUTHOR]

Hybrid organic–inorganic perovskite single crystals, compared with their polycrystalline counterparts in thin films, are free from grain boundaries and have fewer defects, and therefore are promising in high‐performance optoelectronic devices. Recently, the crystal‐structure anisotropy in perovskites has been utilized to achieve polarization‐sensitive photodetectors. Here, it is shown that under 532 nm linearly polarized illumination, although MAPbBr3 (MA=CH3NH3+1) single crystals possess weak in‐plane anisotropy, nanogratings made on the crystal surface lead to high polarization photodetection sensitivity of ≈2.2 comparable with that of the isotropic perovskite crystals and nanowires, while enhancing both the photodetection responsivity and external quantum efficiency. The surface nanopattern induced polarization sensitivity may find interesting applications in future optoelectronic devices. [ABSTRACT FROM AUTHOR]

Halide perovskites are promising emitters for light‐emitting diodes (LEDs) due to their outstanding optoelectronic properties, i.e., tunable bandgap, high photoluminescence quantum efficiency, and excellent color purity. However, in contrast to their green and red cousins, the present blue perovskite LEDs are still suffering from poor operational lifetime and electroluminescence shift during bias operation, hindering their practical applications in full‐color information displays. Developing rational strategies to achieve efficient and stable blue perovskite LEDs is one of the urgent tasks in this community. Herein, through substituting the Pb site with strontium ions, blue perovskite films with stable emission under relatively harsh working conditions, i.e., high electrical bias, constant thermal heating, and UV illumination, are obtained, which accordingly guarantees spectrally stable blue perovskite LEDs with external quantum efficiency of 4.1%. Moreover, different alkaline‐earth metal ions are also investigated to further explore the effects of B‐site ion substitution on the performance of perovskite LEDs. This work demonstrates an alternative path for the development of spectral‐stable blue perovskite LEDs. [ABSTRACT FROM AUTHOR]

• Electro-enhanced activation of PMS overcame the weaknesses of EAOPs and SR-AOPs. • The E-PTi-PMS system achieved an ultra-efficient removal of CBZ (k = 0.467 min-1). • 1O2 played a dominant role and converted from SO 4 • − , O 2 • − , •OH and V o • •. • PTi retained superiorities over wide pH (3–10) and excellent reusability (30 cycles). • The E-PTi-PMS system exhibited the ultra-low energy consumption (0.025 kWh/m3-log). Traditional free radicals-dominated electrochemical advanced oxidation processes (EAOPs) and sulfate radical-based advanced oxidation processes (SR-AOPs) are limited by pH dependence and weak reusability, respectively. To overcome these shortcomings, electro-enhanced activation of peroxymonosulfate (PMS) on a novel perovskite-Ti 4 O 7 composite anode (E-PTi-PMS system) was proposed. It achieved an ultra-efficient removal rate (k = 0.467 min-1) of carbamazepine (CBZ), approximately 36 and 8 times of the E-PTi and PTi-PMS systems. Singlet oxygen (1O 2) played a dominant role in the E-PTi-PMS system and transformed from SO 4 • − , O 2 • − , •OH and oxygen vacancy (V o • •). The electric field expedited the decomposition and utilization of PMS, promoting the generation of radicals and expanding the formation pathway of 1O 2. The E-PTi-PMS system presented superiorities over wide pH (3–10) and less dosage of PMS (1 mM), expanding the pH adaptability and reducing the cost of EAOPs. Simultaneously, the excellent reusability (30 cycles) solved the bottleneck of recycling catalysts in SR-AOPs via an ultra-low energy (0.025 kWh/m3-log). This work provides a promising alternative towards high-efficiency and low-cost treatment of polluted waters. [Display omitted] Schematic of the proposed mechanism for CBZ degradation in the E-PTi-PMS system. [ABSTRACT FROM AUTHOR]