High-Performance Blue Quasi-2D Perovskite Light-Emitting Diodes via Balanced Carrier Confinement and Transfer

Abstract

Extensive investigation of the passivating agents has been performed to suppress the perovskite defects. However, very few attentions have been paid to rationally design the passivating agents for the balance of the carrier confinement and transfer in quasi-2D perovskites, which is essential to achieve high-performance perovskite LEDs (PeLEDs). In this work, tributylphosphine oxide (TBPO) with moderate carbon chain length is demonstrated as a decent passivator for the quasi-2D perovskites by strengthening the carrier confinement for massive radiative recombination within the perovskites, and more importantly providing efficient carrier transfer in the quasi-2D perovskites. Benefiting from these interesting optoelectronic properties of TBPO-incorporated perovskites, we achieve high-efficient blue PeLEDs with an external quantum efficiency up to 11.5% and operational stability as long as 41.1 min without any shift of the electroluminescence spectra. Consequently, this work contributes an effective approach to promote the carrier confinement and transfer for high-performance and stable blue PeLEDs.

Highly Emissive Quasi-2D Perovskites Enabled by a Multifunctional Molecule for Bright Light-Emitting Diodes

“…The interaction between TDP and the perovskite is first shown in the Fourier transform infrared (FT-IR) spectroscopy performed on the TDP and TDP-decorated perovskite (abbreviated as pristine/TDP). As shown in Figure b, the stretching vibration peak at 1089 cm –1 can be assigned to the PO bond of the TDP molecule . Such peak is observed to shift to a lower wavenumber of 1013 cm –1 for the pristine/TDP perovskite, showing a reduced electron cloud density between phosphorus and oxygen owing to the strong interaction between the oxygen atom of PO and Pb 2+ of the perovskite.…”

“…As shown in Figure 1b, the stretching vibration peak at 1089 cm −1 can be assigned to the PO bond of the TDP molecule. 39 Such peak is observed to shift to a lower wavenumber of 1013 cm −1 for the pristine/ TDP perovskite, showing a reduced electron cloud density between phosphorus and oxygen owing to the strong interaction between the oxygen atom of PO and Pb 2+ of the perovskite. To further verify the high affinity between TDP and the perovskite, X-ray photoelectron spectroscopy (XPS) was performed on pristine and pristine/TDP perovskites.…”

“…Therefore, these defects should be effectively passivated to improve the radiative recombination efficiency. The defects are widely reported to be associated with ionic defects such as halide vacancies. , To reduce the halide vacancies, a halide-rich circumstance was reported by providing excess halide ions to saturate the halide vacancies for high emission efficiency. , In addition, molecules with functional groups, such as carboxyl, amidogen, phosphine oxide, etc., show strong binding energies with the unsaturated lead sites, which are adopted to passivate the halide vacancies for strengthened radiative recombination. However, despite the extensive reports of molecule passivators, very few investigations show the synergistic effects of the molecule to simultaneously passivate the defects, suppress the low- n phase, and increase the exciton binding energy, which would all contribute to efficient radiative recombination in the perovskites.…”

51.4: In‐situ Fluorescence Monitoring Technique for Highly Reproducible Perovskite Light‐emitting Diodes

“…At present, the EQEs of near-infrared, red, and green PLEDs have exceeded 20%. and that of blue PLEDs has beyond 10%, demonstrating great potential for practical applications [7][8][9][10][11][12][13][14] . In addition, the progress has been made in the stability of PLEDs with the indepth understanding of perovskite, but the commercialization of PLEDs is still challenging due to the lack of highly reproducible fabrication techniques.…”

“…Among the various solution techniques of film formation, the anti-solvent stripping method is widely employed as it can not only flexibly select different anti-solvents to extract polar solvents with higher boiling points in perovskite films, but also add other soluble trace substances to the anti-solvent, which can then incorporate into the perovskite during anti-solvent extraction. Thus, this method can improve the film quality of perovskite films significantly 13 . Many factors, including the anti-solvent time, annealing temperature, and additives can affect the perovskite film quality.…”