Stable and conductive lead halide perovskites facilitated by X-type ligands

Zhong

et al. 2019

Adv Funct Materials

242

208

Cubic phase CsPbI 3 (α-CsPbI 3 ) perovskite quantum dots (QDs) have received extensive attention due to their all-inorganic composition and suitable band gap (1.73 eV). However, α-CsPbI 3 QDs might convert to δ-CsPbI 3 (orthorhombic phase with indirect band gap of 2.82 eV) due to easy loss of surface ligands. In addition, commonly used long-chain ligands (oleic acid, OA, and oleylamine, OLA) hinder efficient charge transport in optoelectronic devices. In order to relieve these drawbacks, OA, OLA, octanoic acid, and octylamine are used as capping ligands for synthesizing high-quality α-CsPbI 3 QDs. The results indicate that these QDs exhibit excellent optical properties and long-term stability compared to QDs capped only with OA and OLA. Moreover, QDs with shorter ligands exhibit an enhanced charge transport rate, which improves the power conversion efficiency of photovoltaic devices from 7.76% to 11.87%. obtained a solar cell based on C8/C18-CsPbI 3 QDs with a PCE of 11.87%. The PCE produced by this solar cell is much higher than that of devices based on C18-CsPbI 3 QDs (7.76%).

Section: Introductionmentioning

confidence: 99%

Short‐Chain Ligand‐Passivated Stable α‐CsPbI₃ Quantum Dot for All‐Inorganic Perovskite Solar Cells

Zhong

et al. 2019

Adv Funct Materials

242

208

“…Generally, regulating surface ligands is an effective approach to improve stability, including the introduction of long-chain, branched or sterically hindered surfactants, which serve as capping ligands to create surface passivation layers around the NCs. 11,[24][25][26][27][28] Typically, branched (3-aminopropyl) triethoxysilane (APTES), 29 sterically demanding polyhedral oligomeric silsesquioxane (POSS), 30 polydentate chelates, 31 or alkyl phosphate 32 have been employed as passivation layers to yield high stability perovskite NCs.…”

Section: Introductionmentioning

confidence: 99%

Highly Stable Luminous “Snakes” from CsPbX₃ Perovskite Nanocrystals Anchored on Amine-Coated Silica Nanowires

Pan

Jurow

et al. 2018

ACS Appl. Nano Mater.

Despite the exceptional optoelectronic characteristics of perovskite nanocrystals (NCs), the materials' potential applications are primarily limited by their instability arising from the ionic nature of the CsPbX3 (X=Cl, Br and I) lattice, low formation energy and spontaneous ion exchange. Herein, we introduce a facile and effective in-situ growing strategy to prepare extremely stable composites (abbr. CsPbX3@CA-SiO2) by anchoring CsPbX3 NCs onto silica nanowires (NWs), which effectively depresses the optical degradation of their photoluminescence (PL) and enhances stability. The serpentine silica NWs, with tunable lengths of up to 8 μm, are prepared by anisotropic sol-gel growth of hydrolyzed tetraethylorthosilicate (TEOS) with 3aminopropyltriethoxysilane (APTES) and trimethoxy(octadecyl)silane (TMODS) in a water/oil emulsion. The free amino groups are employed as surface ligands for growing perovskite NCs, yielding distributed monodisperse NCs (~8 nm) around the NW matrix. The emission wavelength is tunable by simple variation of the halide compositions (CsPbX3, X=Cl, Br or I) and the composites demonstrate a high photoluminescence quantum yield (PLQY 32-69%). Additionally, we have demonstrated the composites CsPbX3@CA-SiO2 can be self-woven to form a porous 3D hierarchical NWs membrane, giving rise to a superhydrophobic surface with hierarchical micro/nano structural features. Most importantly, the resulting composites exhibit remarkable chemical stability towards water, and much enhanced photostability and thermal stability. This work presents an effective strategy to incorporate perovskite NCs onto functional matrices as multifunctional stable light sources.

“…[26][27][28] Due to their ionic nature, perovskite NCs are rapidly degraded by polar solvents and environmental humidity. 26,[29][30][31] Notable approaches to improving NC stability include polymer encapsulation, 17, 26, 32, 33 incorporation in mesoporous silica particles, 29,34,35 high affinity ligands, [36][37][38] silicone resin, 39 and using bulky capping ligands. 14,40,41 Most of these examples take advantage of the hydrophobicity of the encapsulation layers.…”

mentioning

confidence: 99%

Nanorod Suprastructures from a Ternary Graphene Oxide–Polymer–CsPbX₃ Perovskite Nanocrystal Composite That Display High Environmental Stability

et al. 2017

Despite the exceptional optoelectronic characteristics of the emergent perovskite nanocrystals, the ionic nature greatly limits their stability, and thus restricts their potential applications. Here we have adapted a self-assembly strategy to access a rarely reported nanorod suprastructure that provide excellent encapsulation of perovskite nanocrystals by polymer-grafted graphene oxide layers. Polyacrylic acid-grafted graphene oxide (GO-g-PAA) was used as a surface ligand during the synthesis of the CsPbX perovskite nanocrystals (NCs), yielding particles (5-12 nm) with tunable halide compositions that were homogeneously embedded in the GO-g-PAA matrix. The resulting NC-GO-g-PAA exhibits a higher photoluminescence quantum yield than previously reported encapsulated NCs while maintaining an easily tunable bandgap, allowing for emission spanning the visible spectrum. The NC-GO-g-PAA hybrid further self-assembles into well-defined nanorods upon solvent treatment. The resulting nanorod morphology imparts extraordinary chemical stability toward protic solvents such as methanol and water and much enhanced thermal stability. The introduction of barrier layers by embedding the perovskite NCs in the GO-g-PAA matrix, together with its unique assembly into nanorods, provides a novel strategy to afford robust perovskite emissive materials with environmental stability that may meet or exceed the requirement for optoelectronic applications.