Stable and Efficient Red Perovskite Light-Emitting Diodes Based on Ca ²⁺ -Doped CsPbI ₃ Nanocrystals

Abstract

α-CsPbI3 nanocrystals (NCs) with poor stability prevent their wide applications in optoelectronic fields. Ca2+ (1.00 Å) as a new B-site doping ion can successfully boost CsPbI3 NC performance with both improved phase stability and optoelectronic properties. With a Ca2+/Pb2+ ratio of 0.40%, both phase and photoluminescence (PL) stability could be greatly enhanced. Facilitated by increased tolerance factor, the cubic phase of its solid film could be maintained after 58 days in ambient condition or 4 h accelerated aging process at 120°C. The PL stability of its solution could be preserved to 83% after 147 days in ambient condition. Even using UV light to accelerate aging, the T50 of PL could boost 1.8-folds as compared to CsPbI3 NCs. Because Ca2+ doping can dramatically decrease defect densities of films and reduce hole injection barriers, the red light-emitting diodes (LEDs) exhibited about triple enhancement for maximum the external quantum efficiency (EQE) up to 7.8% and 2.2 times enhancement for half-lifetime of LED up to 85 min. We believe it is promising to further explore high-quality CsPbI3 NC LEDs via a Ca2+-doping strategy.

Efficient Pure Blue Light-Emitting Diodes Based on CsPbBr3 Quantum-Confined Nanoplates

“…SA has a short carbon chain and a conjugated aromatic ring, for which conductivity should be much higher than for classic ligands. The hole migration rates were estimated by fitting the space-charge-limited-current region with Child’s law where ε 0 is the vacuum permittivity; ε is the average relative dielectric constant of CsPbBr 3 (ε ≈ 22). , L is the thickness of the perovskite film; and J , μ, and V are the measured current density, carrier migration rates, and applied voltage, respectively.…”

“…The hole migration rates were estimated by fitting the space-charge-limited-current region with Child's law. 41 εε μ…”

Bright and stable quaternary ammonium antimony halides for solid-state lighting

“…Lead halide perovskite materials have been extensively studied in light-emitting diodes (LEDs) due to their high photoluminescence quantum yields (PLQYs) with tunable wavelengths and gradually improved stability. 1–10 Compared to all-inorganic lead halides, organic–inorganic hybrid lead halides exhibit tunable optical and physical properties because of the flexible structure and size of their organic molecules. 11–15 Several recent studies have demonstrated that MAPbX 3 and FAPbX 3 have high PLQYs, and narrow full width at half maxima (FWHMs).…”

Environmentally Friendly Syntheses of Self-Healed and Printable CsPbBr3 Nanocrystals

“…Currently, hot-injection and room temperature recrystallization methods have been well developed to synthesize high-quality perovskite NCs. − However, both methods suffered from the problem of solvent toxicity. − Although one type of no-solvent method, e.g., the mechanochemical method, , has been developed to avoid toxic solvents, the perovskite NCs acquired with this approach have relatively low photoluminescence quantum yields (PLQYs) and are hardly solution-processable. Along with the surge of a global green wave, reducing or eliminating the use of toxic solvents is imperative and developing high-performance and green solution-processable perovskite NCs is desired.…”