A simple and versatile in situ fabrication of MAPbX nanocrystal-embedded polymer composite films is developed by controlling the crystallization process from precursor solutions. The composite films exhibit enhanced photoluminescence properties, improved stability, and excellent piezoelectric and mechanical properties. Applications of these composite films as color converters in liquid-crystal-display backlights are demonstrated, showing bright potential in display technology.

The off‐stoichiometry effects and gram‐scale production of luminescent CuInS2‐based semiconductor nanocrystals, as well as their application in electroluminescence devices are reported. The crystal structures and optical properties of CuInS2 nanocrystals can be significantly influenced by controlling their [Cu]/[In] molar ratio. A simple model adapted from the bulk materials is proposed to explain their off‐stoichiometry effects. Highly emissive and color‐tunable CuInS2‐based NCs are prepared by a combination of [Cu]/[In] molar ratio optimization, ZnS shell coating, and CuInS2–ZnS alloying. The method is simple, hassle‐free, and easily scalable to fabricate tens of grams of nanocrystal powders with photoluminescence quantum yields up to around 65%. Furthermore, the performance of high‐quality CuInS2‐based NCs in electroluminescence devices is examined. These devices have lower turn‐on voltages of around 5 V, brighter luminance up to approximately 2100 cd m−2 and improved injection efficiency of around 0.3 lm W−1 (at 100 cd m−2) in comparison to recent reports.

CuInS2 nanocrystals are viewed as very good candidates for solar harvesting and light emitting applications. Here we report an optimized noninjection method for the synthesis of monodisperse pyramidal CuInS2 nanocrystals with sizes ranging from 3 to 8 nm. This synthetic route is able to yield large amounts of high quality nanoparticles, usually in the gram scale for one batch experiment. The structure and surface studies showed that the resulting nanocrystals are pyramids of CuInS2 tetragonal phase with well-defined facets, while their surface is functionalized with dodecanethiol capping ligands. Spectroscopic and electrochemical measurements revealed size-dependent optical and electrical properties of CuInS2 nanocrystals, demonstrating quantum confinement effects in these systems. The size-dependent optical bandgaps of CuInS2 nanocrystals were found to be consistent with the finite-depth well effective mass approximation (EMA) calculations, which provide a convenient method to estimate the diameter of CuInS2 pyramids. Additionally we have also determined some important physical parameters, including bandgaps and energy levels, for this system, which are crucial for the integration of CuInS2 nanocrystals in potential device applications.

In the past 5 years, colloidal I-III-VI nanocrystals such as CuInS2, CuInSe2, and AgInS2 have been intensively investigated for the potential to replace commonly available colloidal nanocrystals containing toxic elements in light-emitting and solar-harvesting applications. Many researchers from different disciplines are working on developing new synthetic protocols, performing spectroscopic studies to understand the luminescence mechanisms, and exploring various applications. To achieve enhanced performance, it is very desirable to obtain high-quality materials with tunable luminescence properties. In this Perspective, we highlight the current progress on tuning the luminescence properties of I-III-VI nanocrystals, especially focusing on the advances in the synthesis, spectroscopic properties, as well as the primary applications in light-emitting devices and bioimaging techniques. Finally, we outline the challenges concerning luminescent I-III-VI NCs and list a few important research tasks in this field.