Synergistic Regulation Effect of Nitrate and Calcium Ions for Highly Luminescent and Robust α‐CsPbI₃ Perovskite

Abstract

The α‐CsPbI3 nanocrystals (NCs) easily transform into yellow non‐perovskite, accompanying with declining photoelectric properties that restricting their practical applications in diverse fields. Herein, the highly luminescent and robust α‐CsPbI3 NCs is achieved through engineering the lattice symmetry of perovskite, enabled by the synergistic effect of NO3− ion passivation and Ca2+ ion doping. The introduced NO3− ions enhance the phase‐change energy barrier and the surface steric hindrance, thus promoting the formation of α‐CsPbI3 NCs with hyper‐symmetric crystal structure, while the Ca2+ ion doping contributes to improving their lattice symmetry by significant regulation of the tolerance factor. As a result, the obtained α‐CsPbI3 NCs display an outstanding photoluminescence quantum yield of 96.6%, together with the reduced defect state density and eminent conductivity. Most importantly, the as‐engineered α‐CsPbI3 NCs exhibit excellent stability under ambient conditions for 9 months and UV illumination for 32 h. It displays brilliant thermal stability, maintaining luminous intensity for 15 min under 140 °C, and performing desired durability and reversibility, evidenced by 160 °C cyclic test and 120 °C reversibility test. Given enhanced robustness, the as‐engineered α‐CsPbI3 NCs based light‐emitting‐diode devices are constructed, exhibiting a power efficiency of 105.3 lm W−1 and the excellent working stability for 18 h.

Highly stable lanthanide-doped CsPbI3 perovskite nanocrystals with near-unity quantum yield for efficient red light-emitting diodes

“…CsPbI 3 NCs have a small t of around 0.89, which results in serious structural distortion for a metastable phase. 11,12 The cubic CsPbI 3 NCs tend to transform into the non-photoactive orthorhombic (δ) phase under humid or thermal stress conditions. [13][14][15] The distorted structure of cubic CsPbI 3 NCs also prompts the formation of massive trap states during crystal growth, which undoubtedly aggravates the luminescence performance of CsPbI 3 NCs.…”

Synergistic regulation effect of magnesium and acetate ions on structural rigidity for synthesizing an efficient and robust CsPbI3 perovskite toward red light-emitting devices

“…As displayed in Fig. 2a, the peaks at 2800–3010 cm −1 are attributed to the asymmetric stretching of C–H in the alkyl chain, 38 and the peak of the N–H bending vibration of RNH 3 + is at 1640 cm −1 . The peak at 1400–1560 cm −1 is related to the C–O bending vibration of carboxylate (RCOO − ).…”

“…As displayed in Fig. 2a, the peaks at 2800-3010 cm −1 are attributed to the asymmetric stretching of C-H in the alkyl chain, 38 and the peak of the N-H bending vibration of RNH 3 + is at…”

“…This eventually enhances the structural rigidity of the perovskite. 38 Meanwhile, the Mg 2+ ions passivate the Pb 2+ vacancy to advance the structural rigidity due to its small ionic radius. The above results demonstrate that the AcO − and Mg 2+ ion passivation is crucial for the regulation of the structural rigidity of CsPbI 3 NCs.…”

Recent Progress of Halide Perovskites Applied to Five Senses Sensors

“…However, studies on sensors related to auditory sensing are limited. Studies related to LEDs manufactured using halide perovskites have significantly progressed using these three ions. − If attention is focused here, significant progress will be made in research to implement taste sensors. In addition, further studies on magnetic sensors for auditory sensing are required.…”