and carrier injection balance management, [23] the external quantum efficiency (EQE) of PeLEDs has exceeded 20% in near-infrared/red and green emission regions. Nevertheless, most high-performance PeLEDs were fabricated by a spin-coating method with device areas around few square millimeters. [14,16,[19][20][21] Recently, large-area PeLEDs have attracted growing attentions due to their potential applications in solid-state lighting, and a number of breakthroughs have been made. [24][25][26][27] For example, spin coating was tried to make large-area nearinfrared and green PeLEDs with device areas of 9 cm 2 . [24,25] A thermal evaporation method was also utilized to fabricate largearea green PeLEDs up to 40.2 cm 2 with a peak EQE of 7.1%. [26] We recently developed a robust blade-coating technique to fabricate large-area and efficient infrared/ red PeLEDs. [27] Diluted and organoammonium-excessed precursors were adopted to increase the film formation speed, which resulted in ultra-flat films with roughness around 1 nm. The EQE reached 16.1% with a device area of 4 mm 2 , and a large-area device up to 28 cm 2 with uniform emission was also demonstrated.It is still very challenging to fabricate blue PeLEDs, particularly large-area blue PeLEDs, which were generally made from cesium-based mixed bromide-chloride perovskites, CsPb(Br x Cl 1−x ) 3 (x ≈ 0.4-0.8). [11,28] The solubility of Large-area fabrication of perovskite light-emitting diodes (PeLEDs) through mass-production techniques has attracted growing attention due to their potential applications in lighting. Several breakthroughs are made for red/ infrared and green emissions. Nevertheless, large-area blue/sky-blue PeLEDs, a requisite color for lighting, have not yet been reported. Here, efficient and large-area sky-blue PeLEDs are fabricated through blade-coating supersaturated precursors. The volume ratio of dimethyl sulfoxide to dimethylformamide is tuned to obtain a supersaturated CsPb(Br 0.84 Cl 0.16 ) 3 solution. Blade-coating this supersaturated precursor results in nucleation in the solution phase with much higher nucleation sites, and a faster crystallization rate. The uniform films formed by this approach exhibit smaller grain size, lower trap density, and higher radiative recombination rate. The peak external quantum efficiency of the blade-coated PeLEDs reaches 10.3% with sky-blue emission (489 nm). Benefitting from the robustness of this blade-coating technique, large-area sky-blue PeLEDs with a device area of 28 cm 2 are also achieved with uniform emission. This work represents a significant step forward toward flat-panel lighting and full-color display for the PeLEDs.
Chiral pumping from optical electric fields oscillating at THz frequencies is observed in the Weyl material TaAs with electric and magnetic fields aligned along both the a-and c-axes. Free carrier spectral weight enhancement is measured directly for the first time, confirming theoretical expectations of chiral pumping. A departure from linear field-dependence of the Drude weight is observed at the highest fields in the quantum limit, providing direct evidence of field-dependent Fermi velocity of the chiral Landau level. Implications for the chiral magnetic effect in Weyl semimetals from the optical f -sum rule are discussed. arXiv:1810.05660v4 [cond-mat.mes-hall]
Inverted perovskite solar cells (PSCs) with PEDOT:PSS as hole transporting layers exhibit tremendous prospects for flexible photovoltaic applications owing to their characteristics of low-temperature solution processability and favorable flexibility. Nevertheless, the energy level mismatch of PEDOT:PSS and perovskite layer results in a severe energy deficit. In addition, the acidity of PEDOT:PSS is detrimental to the stability of devices. To address these issues, we employ a glyceryl monostearate (GMS) interlayer to improve the work function and conductivity of PEDOT:PSS. Meanwhile, it can passivate the traps at the interface of PEDOT:PSS/perovskite. As a consequence, the champion power conversion efficiencies of photovoltaic devices based on MAPbI 3 films increase from 14.82% to 17.29% due to the surface modification of PEDOT:PSS with GMS, which is mainly ascribed to the enhanced open-circuit voltage and short-circuit current density. Furthermore, the nonencapsulated MAPbI 3 perovskite films and devices based on GMS-modified PEDOT:PSS show much better moisture stability and thermal stability than the counterparts without GMS modification.
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.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.