Highly Luminescent Colloidal Nanoplates of Perovskite Cesium Lead Halide and Their Oriented Assemblies

Abstract

Anisotropic colloidal quasi-two-dimensional nanoplates (NPLs) hold great promise as functional materials due to their combination of low dimensional optoelectronic properties and versatility through colloidal synthesis. Recently, lead-halide perovskites have emerged as important optoelectronic materials with excellent efficiencies in photovoltaic and light-emitting applications. Here we report the synthesis of quantum confined all inorganic cesium lead halide nanoplates in the perovskite crystal structure that are also highly luminescent (PLQY 84%). The controllable self-assembly of nanoplates either into stacked columnar phases or crystallographic-oriented thin-sheet structures is demonstrated. The broad accessible emission range, high native quantum yields, and ease of self-assembly make perovskite NPLs an ideal platform for fundamental optoelectronic studies and the investigation of future devices.

Colloidal lead halide perovskite nanocrystals: synthesis, optical properties and applications

“…Syntheses of nanoplatelets often produce mixtures of nanoplatelets with different thickness, which have proven to be difficult to separate, limiting studies aiming to understand the thickness-dependent optical properties of perovskite nanoplatelets. 25,92 In spite of these difficulties, theoretical models have been developed to understand the quantum size effects of perovskite NCs and, with some improvement, experimental studies will be able to confirm or refute these results. 25,87 In spite of the recent advances in synthesis, not many studies exist concerning the photophysics of perovskite NCs; this area will definitely become more active and studies exploring carrier relaxation and charge transfer processes will follow.…”

“…Kovalenko and colleagues 24 reported size-dependent PL emission from square-shaped CsPbBr 3 NCs, in which the PL peak gradually blue shifted from 512 to 460 nm as the edge size decreased from 11.8 to 3.8 nm. Alivisatos and colleagues 92 reported the synthesis of quantum-confined highly fluorescent (PLQY 84%) CsPbX 3 perovskite nanoplatelets (Figures 6c-e). They showed that the thickness of CsPbBr 3 nanoplatelets can be tuned from 1 to 5 unit cells thick by changing the reaction temperature, with the monolayer platelets emitting at 400 nm (Figure 6e), whereas the bulk-like crystals emitted at 520 nm (Figure 6d).…”

Polymer-Enhanced Stability of Inorganic Perovskite Nanocrystals and Their Application in Color Conversion LEDs

“…2,[5][6][7] Compared to classical Cd-based chalcogenide quantum dots (QDs), CsPbX 3 (X = Cl, Br, I) offer a very broad and easily adjustable composition versatility together with ample options for shape control, which allow tuning of their emission wavelength throughout the whole visible spectrum. [8][9][10][11][12][13][14] Among other applications, such highly luminescent and spectrally tunable NCs are ideally suited to produce monochromatic and white LEDs (WLEDs). 15 In this regard, CsPbX 3 NCs have been utilized as the emissive layer in electroluminescent monochromatic and color conversion QD-LEDs showing exceptionally narrow emission bandwidths and thus high color quality in devices.…”

Real-Space Mapping of Surface Trap States in CIGSe Nanocrystals Using 4D Electron Microscopy

“…4D scanning ultrafast electron microscopy, surface traps, charge carrier dynamics, CIGSe, semiconductor nanocrystals, shelling 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 3 With their manifold tunable properties and cost-effective versatile chemical processability, research in colloidal semiconductor nanocrystals (NCs) have spanned from vast materials systems to their widespread applications in light emitting diodes, sensors and light harvesters. [1][2][3][4][5][6][7][8][9][10] However, due to high surface-to-volume ratio of these NCs, the large number of unpassivated atoms on their surfaces lead to the formation of highly dense trap states, which serve as undesirable, non-radiative deactivation channels for photo-generated charge carriers. [11][12][13][14][15] This often acts as a bottleneck in the use of these NCs for photoactive applications.…”