Ambient fabrication of efficient triple cation perovskite-based near-infrared light-emitting diodes

Abstract

In addition to their widespread use as an outstanding light-harvesting material, solution-based organometallic halide perovskites have also recently emerged as a promising material for light-emitting diode (LED) applications. However, their stability under an ambient environment remains a challenge. Triple cation perovskites offer an appealing solution as it reduces the sensitivity to the processing conditions and improves the purity of the perovskite films. This work describes a facile ambient-processed thiocyanate-doped triple-cation perovskite Csx(MA0.17FA0.83)Pb(100-x)(I0.83Br0.17)3 used for high-performance perovskite-based LEDs with peak emission at 750 nm. Using the perovskite film tailoring technique by mixing DMF (N,N-Dimethylmethanamide) with perovskite precursor, we are able to reduce the perovskite grain size and optimize the film thickness while preserving its crystalline structure. With optimized processing techniques, we achieve a ∼90% improvement of the perovskite LEDs external quantum efficiency (EQE) from ∼3.1% to ∼5.9%. We believe this triple cation perovskite synthesis approach and film tailoring technique yields excellent device performances and constitutes a significant step towards low-cost and efficient LEDs.

Recent Progress in Mixed A‐Site Cation Halide Perovskite Thin‐Films and Nanocrystals for Solar Cells and Light‐Emitting Diodes

“…[226] Similarly, the incorporation of guanidine ions into CsPbBr x Cl 3−x reported by Zhang et al did not alter the phase of the films. [215] However, when the A-site cations were large enough to no longer fit into the cuboctahedral voids in the perovskite, such as [161] Cs x (MA 0.17 FA 0.83 ) [162] Cs y GA 1−y PbBr x Cl 3−x ITO/PEDOT:PSS/PTAA/Pero/TPBi/LiF/Al 490 (18) 3.02 603 2.6 2021 [215] Cs y FA [173] Cs x (MA 0.17 FA 0.83 )Pb(I 0.83 Br 0.17 ) 3 ITO/PEDOT:PSS/Pero/F8/MoO 3 /Ag 750 5.9 986 3 2022 [205] Cs 10 (MA 0.17 FA 0.83 )Pb(Br x I 1−x ) [214] Cs 0.5 FA 0.5 PbBr 3 ITO/NiO x /TFB/Pero/TPBi/LiF/Al 526 12.1 15 070 2021 [206] phenethylammonium ions (PEA + ), the bulky cations would cut the bulk 3D structure into quantum-confined 2D structures or quasi-2D structures. The progress of quasi-2D PeLED is beyond the scope of this review.…”

“…In general, double [14,161,204,206,207] and triple cation [162,205,219,220] perovskite emitters show higher performance and operational stability than single-cation perovskites. A variety of possible explanations have been put forward, including passivation effects, improvements in film crystallinity, and increased hydrogen bonding between the amine group of the alkylammonium cation and the halides from the inorganic octahedra.…”

“…Many studies have shown that by having multiple cations at A‐site such as FA, MA, or Cs, the external quantum efficiency (EQE) of LED is higher than in mono‐cation perovskite LEDs. [ 14,173,204–207 ] For example, Zhang et al. conducted a systematic investigation into the effect of mixing FA and Cs on the performance of perovskite LEDs.…”

“…Many studies have shown that by having multiple cations at A-site such as FA, MA, or Cs, the external quantum efficiency (EQE) of LED is higher than in mono-cation perovskite LEDs. [14,173,[204][205][206][207] For example, Zhang et al conducted a systematic investigation into the effect of mixing FA and Cs on the performance of perovskite LEDs. [173] The study showed that alloying up to 20% Cs influenced the perovskite crystal lattice and improved the device performance from maximum luminance of 8563 cd m −2 and EQE of 0.82% for neat FAPbBr 3 LEDs to 55 005 cd m −2 and 2.8% for FA 0.8 Cs 0.2 PbBr 3 LEDs.…”

Two-Photon Absorption and Photoluminescence of Individual CsPbBr3 Nanocrystal Superlattices

“…Perovskite micro- and nanostructures have attracted considerable attention in recent years due to their versatile optoelectronic responses, − which have been widely used for photovoltaic devices, high-brightness light-emitting diodes, low-threshold lasers, and photodetectors . Due to their structural and chemical diversity, flexible tunability, and strong oscillation strength, perovskite structures are also very useful for enhanced nonlinear optical responses, , e.g., light modulators, multiphoton microscopy, lithography, and terahertz generation .…”