Stable Luminescent CsPbI₃ Quantum Dots Passivated by (3-Aminopropyl)triethoxysilane

Abstract

Perovskite nanomaterials have been fascinating for commercial applications and fundamental research owing to their excellent optical properties and satisfactory processability. They are expected to be alternative downconversion materials in phosphor-converted LEDs for lighting or display technology. However, owing to their low formation energy and large specific surface area, perovskite nanomaterials are sensitive to environmental stress like humidity, heat, etc. In this paper, cubic CsPbI 3 quantum dots (QDs) with improved stability are synthesized using (3-aminopropyl)triethoxysilane (APTES). These luminescent CsPbI 3 QDs passivated by APTES not only show excellent stability when stored in hexane but also possess outstanding steadiness for lattice structure when prepared as a thin film in open air. They do not decompose immediately in the water. Such excellent stability is attributed to the hindrance from hydrolysis of APTES, which forms an analogous core−shell structure to protect the "core" CsPbI 3 QDs. Furthermore, an additional iodine source is added to enhance their emissionm and CsPbI 3 QDs with a PLQY of 84% are synthesized.

Large‐Scale Production of Ligand‐Engineered Robust Lead Halide Perovskite Nanocrystals by a Droplet‐Based Microreactor System

“…So we got γ‐CsPbI 3 NCs in orthorhombic crystal with Pbnm space group (ICSD‐21955) and reduced symmetry, a more stable black phase of CsPbI 3 crystal at room temperature, [ 45 ] rather than in cubic phase. [ 36 ] The lattice spacing measurements in Figure , Supporting Information, also demonstrate this. Although the ICSD cards of the two crystal forms are somewhat similar, after zooming in, the obvious difference in the diffraction angle can be seen in the small image in the upper Figure 1h.…”

“…In previous research work, [ 36 ] APTES and OAm‐HI were used synergistically as basic ligands, to form the protective layer, confine the growth of CsPbI 3 , and eliminated partial surface trapping defects and iodine vacancies. The particle size and bandgap energy can be tuned by changing the ratio of APTES and OAm‐HI.…”

Room-Temperature Synthesis of Air-Stable Near-Infrared Emission in FAPbI3 Nanoparticles Embedded in Silica

“…The APTES molecule provides Si–O bonds which generate the Si–O–Si ligands through hydrolysis and dehydration in the reaction to package PNPs. This protects PNPs from environmental factors [ 39 , 40 , 41 ]. Therefore, to verify Si–O–Si ligands on the surface of PNCs, a FTIR spectrum was used to prove the silica wrapping ( Figure 2 ).…”

Surface Passivation Strategies for Improving Photoluminescence and Stability of Cesium Lead Halide Perovskite Nanocrystals

“…In addition to their colloidal stability, CsPbI 3 perovskite NCs passivated by (3‐aminopropyl)triethoxysilane (APTES), they exhibited outstanding stability when prepared as films also. Their stability against water is imputed to its resistance from hydrolysis of APTES, by forming core‐shell like structure to protect the as‐called core CsPbI 3 NCs from water (See Figure 8B) [94] . Later, it was proved that potassium bromide surface passivation on CsPbI 3‐x Br x NCs aid for the development of stable and efficient perovskite red‐emitting diode NCs and their respective PL decay profiles are presented in Figure 9.…”

“…Their stability against water is imputed to its resistance from hydrolysis of APTES, by forming core-shell like structure to protect the as-called core CsPbI 3 NCs from water (See Figure 8B). [94] Later, it was proved that potassium bromide surface passivation on CsPbI 3-x Br x NCs aid for the development of stable and efficient perovskite redemitting diode NCs and their respective PL decay profiles are presented in Figure 9. The maximum luminance of 2671 cd/m 2 and EQE 3.55% was achieved by the device with KBr-passivated CsPbI 3-x Br x NCs and the device characteristics are presented in Figure 10.…”