The ability to synthesize a diverse spectrum of one-dimensional (1D) nanocrystals presents an enticing prospect for exploring nanoscale size- and shape-dependent properties. Here we report a general strategy to craft a variety of plain nanorods, core-shell nanorods, and nanotubes with precisely controlled dimensions and compositions by capitalizing on functional bottlebrush-like block copolymers with well-defined structures and narrow molecular weight distributions as nanoreactors. These cylindrical unimolecular nanoreactors enable a high degree of control over the size, shape, architecture, surface chemistry, and properties of 1D nanocrystals. We demonstrate the synthesis of metallic, ferroelectric, upconversion, semiconducting, and thermoelectric 1D nanocrystals, among others, as well as combinations thereof.

A copper zinc tin sulfide (CZTS) semiconductor can be used as an effective counter‐electrode (CE) material in place of platinum metal, yielding low‐cost, high‐efficiency dye‐sensitized solar cells (DSSCs). CZTS nanocrystals were synthesized and then spin‐coated on fluorine‐doped tin oxide (FTO) glass. After selenization, the power conversion efficiency of the resulting DSSC was comparable that with a Pt CE.

ganic CsPbX 3 QDs possess narrow full width at half maximum (FWHM) of emission (as small as 12 nm) and excellent quantum yield (QY: 50-90%). [1,8] They have a Bohr diameter up to 12 nm, [1] exhibiting a size-tunable bandgap in the visible region. It is also notable that the exchange of halide ions (Cl − , Br − , and I − ) in as-synthesized perovskite QDs is highly effective, rendering easy and rapid access to a wide range of perovskite QDs with tunable absorption and photoluminescence (PL) spectra. [1] In spite of significant advances in perovskite research noted above, a key to the success of perovskite-based materials and devices is the stability of perovskites as they are susceptible to decomposition due to their ionic crystal nature. [7,9] Recently, several methods including coating with alumina by atomic layer deposition, [10] partial coating with SiO 2 via sol-gel process, [11] physical mixing with hydrophobic polymers, [12] and encapsulation within mesoporous silica [7] or polymer beads [13] have proven to be effective in improving stability in polar and ambient environments. However, nearly all approaches described above for stability enhancement result in nanocomposites with multiple perovskite QDs encapsulated in microscopic protective matrices. These microscale nanocomposites may be disadvantageous for biomedical applications where cellular uptake is more feasible for smaller nanoscopic particles, [14] or LEDs where the processing of nanoscopic luminescent particles often leads to low scattering loss, higher loading and packing density, and thus film uniformity. [11] Clearly, the ability to deliberately and reliably improve the stability of perovskite QDs (e.g., against humidity and polar solvents) while retaining their individual nanometer size represents a critical step that underpins future advances in optoelectronic and biological applications.Herein, we report a general and robust strategy by capitalizing on judiciously designed amphiphilic star-like diblock copolymers with well-controlled molecular weight and low polydispersity of each block as molecularly engineered nanoreactors to craft uniform perovskite QDs. Remarkably, these QDs simultaneously possess precisely tunable dimensions Instability of perovskite quantum dots (QDs) toward humidity remains one of the major obstacles for their long-term use in optoelectronic devices. Herein, a general amphiphilic star-like block copolymer nanoreactor strategy for in situ crafting a set of hairy perovskite QDs with precisely tunable size and exceptionally high water and colloidal stabilities is presented. The selective partition of precursors within the compartment occupied by inner hydrophilic blocks of star-like diblock copolymers imparts in situ formation of robust hairy perovskite QDs permanently ligated by outer hydrophobic blocks via coprecipitation in nonpolar solvent. These size-and compositiontunable perovskite QDs reveal impressive water and colloidal stabilities as the surface of QDs is intimately and permanently ligated by a layer of outer ...

The ability to dynamically organize functional nanoparticles (NPs) via the use of environmental triggers (temperature, pH, light, or solvent polarity) opens up important perspectives for rapid and convenient construction of a rich variety of complex assemblies and materials with new structures and functionalities. Here, we report an unconventional strategy for crafting stable hairy NPs with light-enabled reversible and reliable self-assembly and tunable optical properties. Central to our strategy is to judiciously design amphiphilic star-like diblock copolymers comprising inner hydrophilic blocks and outer hydrophobic photoresponsive blocks as nanoreactors to direct the synthesis of monodisperse plasmonic NPs intimately and permanently capped with photoresponsive polymers. The size and shape of hairy NPs can be precisely tailored by modulating the length of inner hydrophilic block of star-like diblock copolymers. The perpetual anchoring of photoresponsive polymers on the NP surface renders the attractive feature of self-assembly and disassembly of NPs on demand using light of different wavelengths, as revealed by tunable surface plasmon resonance absorption of NPs and the reversible transformation of NPs between their dispersed and aggregated states. The dye encapsulation/release studies manifested that such photoresponsive NPs may be exploited as smart guest molecule nanocarriers. By extension, the star-like block copolymer strategy enables the crafting of a family of stable stimuli-responsive NPs (e.g., temperature- or pH-sensitive polymer-capped magnetic, ferroelectric, upconversion, or semiconducting NPs) and their assemblies for fundamental research in self-assembly and crystallization kinetics of NPs as well as potential applications in optics, optoelectronics, magnetic technologies, sensory materials and devices, catalysis, nanotechnology, and biotechnology.