A Non-Conjugated Polymer Acceptor for Efficient and Thermally Stable All-Polymer Solar Cells

A non-conjugated polymer acceptor PF1-TS4 was firstly synthesized by embedding a thioalkyl segment in the mainchain, which shows excellent photophysical properties on par with a fully conjugated polymer, with a low optical band gap of 1.58 eV and a high absorption coefficient >10⁵ cm⁻¹, a high LUMO level of −3.89 eV, and suitable crystallinity. Matched with the polymer donor PM6, the PF1-TS4-based all-PSC achieved a power conversion efficiency (PCE) of 8.63 %, which is ≈45 % higher than that of a device based on the small molecule acceptor counterpart IDIC16. Moreover, the PF1-TS4-based all-PSC has good thermal stability with ≈70 % of its initial PCE retained after being stored at 85 °C for 180 h, while the IDIC16-based device only retained ≈50 % of its initial PCE when stored at 85 °C for only 18 h. Our work provides a new strategy to develop efficient polymer acceptor materials by linkage of conjugated units with non-conjugated thioalkyl segments.     

A General Strategy for Hollow Metal-Phytate Coordination Complex Micropolyhedra Enabled by Cation Exchange

The ability to incorporate functional metal ions (Mⁿ⁺) into metal–organic coordination complexes adds remarkable flexibility in the synthesis of multifunctional organic–inorganic hybrid materials with tailorable electronic, optical, and magnetic properties. We report the cation-exchanged synthesis of a diverse range of hollow Mⁿ⁺-phytate (PA) micropolyhedra via the use of hollow Co²⁺-PA polyhedral networks as templates at room temperature. The attributes of the incoming Mⁿ⁺, namely Lewis acidity and ionic radius, control the exchange of the parent Co²⁺ ions and the degree of morphological deformation of the resulting hollow micropolyhedra. New functions can be obtained for both completely and partially exchanged products, as supported by the observation of Ln³⁺ (Ln³⁺=Tb³⁺, Eu³⁺, and Sm³⁺) luminescence from as-prepared hollow Ln³⁺-PA micropolyhedra after surface modification with dipicolinic acid as an antenna. Moreover, Fe³⁺- and Mn²⁺-PA polyhedral complexes were employed as magnetic contrast agents.     

Doped Zero-Dimensional Cesium Zinc Halides for High-Efficiency Blue Light Emission

All-inorganic zero-dimensional (0D) metal halides have recently received increasing attention due to their excellent photoluminescence (PL) performance and high stability. Herein, we present the successful doping of copper(I) into 0D Cs₂ZnBr₄. The incorporating of Cu⁺ cations enables the originally weakly luminescent Cs₂ZnBr₄ to exhibit an efficient blue emission centered at around 465 nm, with a high photoluminescence quantum yield (PLQY) of 65.3 %. Detailed spectral characterizations, including ultrafast transient absorption (TA) techniques, were carried out to investigate the effect of Cu⁺ dopants and the origin of blue emission in Cs₂ZnBr₄:Cu. To further study the role of the A-site cation and halogen, A₂ZnCl₄:Cu (A=Cs, Rb) were also synthesized and found to generate intense sky-blue emission (PLQY≈73.1 %). This work represents an effective strategy for the development of environmentally friendly, low-cost and high-efficiency blue-emitting 0D all-inorganic metal halides.     

Non-Lithography Hydrodynamic Printing of Micro/Nanostructures on Curved Surfaces

A key issue of micro/nano devices is how to integrate micro/nanostructures with specified chemical components onto various curved surfaces. Hydrodynamic printing of micro/nanostructures on three-dimensional curved surfaces is achieved with a strategy that combines template-induced hydrodynamic printing and self-assembly of nanoparticles (NPs). Non-lithography flexible wall-shaped templates are replicated with microscale features by dicing a trench-shaped silicon wafer. Arising from the capillary pumped function between the template and curved substrates, NPs in the colloidal suspension self-assemble into close-packed micro/nanostructures without a gravity effect. Theoretical analysis with the lattice Boltzmann model reveals the fundamental principles of the hydrodynamic assembly process. Spiral linear structures achieved by two kinds of fluorescent NPs show non-interfering photoluminescence properties, while the waveguide and photoluminescence are confirmed in 3D curved space. The printed multiconstituent micro/nanostructures with single-NP resolution may serve as a general platform for optoelectronics beyond flat surfaces.     

Evanescent Wave-Guided Growth of an Organic Supramolecular Nanowire Array

The ordered assembly of molecules within a specific space of nanoscale, such as a surface, holds great promise in advanced micro-/nanostructure fabrication for various applications. Herein, we demonstrate the evanescent wave (EW)-guided organization of small molecules into a long-range ordered nanowire (NW) array. Experiment and simulation revealed that the orientation and periodicity of the NW array were feasibly regulated by altering the propagation direction and the wavelength of EW. The generality of this approach was demonstrated by using different molecule precursors. While existing studies on EW often took advantages of its near-field property for optical sensing, this work demonstrated the photochemical power of EW in the guided-assembly of small molecules for the first time. It also provides an enlightening avenue to periodic structure with fluorescence, promising for super-resolution microscopy and important devices applicable to optical and bio-related fields.     

Facile Preparation of WO3−x Dots with Remarkably Low Toxicity and Uncompromised Activity as Co-reactants for Clinical Diagnosis by Electrochemiluminescence

The exceptional nature of WO_3−x dots has inspired widespread interest, but it is still a significant challenge to synthesize high-quality WO_3−x dots without using unstable reactants, expensive equipment, and complex synthetic processes. Herein, the synthesis of ligand-free WO_3−x dots is reported that are highly dispersible and rich in oxygen vacancies by a simple but straightforward exfoliation of bulk WS₂ and a mild follow-up chemical conversion. Surprisingly, the WO_3−x dots emerged as co-reactants for the electrochemiluminescence (ECL) of Ru(bpy)₃²⁺ with a comparable ECL efficiency to the well-known Ru(bpy)₃²⁺/tripropylamine (TPrA) system. Moreover, compared to TPrA, whose toxicity remains a critical issue of concern, the WO_3−x dots were ca. 300-fold less toxic. The potency of WO_3−x dots was further explored in the detection of circulating tumor cells (CTCs) with the most competitive limit of detection so far.     

Single-Atom Electrocatalysts from Multivariate Metal–Organic Frameworks for Highly Selective Reduction of CO2 at Low Pressures

Single-atom catalysts (SACs) are of great interest because of their ultrahigh activity and selectivity. However, it is difficult to construct model SACs according to a general synthetic method, and therefore, discerning differences in activity of diverse single-atom catalysts is not straightforward. Herein, a general strategy for synthesis of single-atom metals implanted in N-doped carbon (M₁-N-C; M=Fe, Co, Ni and Cu) has been developed starting from multivariate metal–organic frameworks (MOFs). The M₁-N-C catalysts, featuring identical chemical environments and supports, provided an ideal platform for differentiating the activity of single-atom metal species. When employed in electrocatalytic CO₂ reduction, Ni₁-N-C exhibited a very high CO Faradaic efficiency (FE) up to 96.8 % that far surpassed Fe₁-, Co₁- and Cu₁-N-C. Remarkably, the best-performer, Ni₁-N-C, even demonstrated excellent CO FE at low CO₂ pressures, thereby representing a promising opportunity for the direct use of dilute CO₂ feedstock.     

Divergent Total Synthesis of Euphoranginol C,Euphoranginone D,ent-Trachyloban-3β-ol,ent-Trachyloban-3-one,Excoecarin E,and ent-16α-Hydroxy-atisane-3-one

A divergent synthetic approach to biogenetically related diterpenoids such as ent-kauranes, ent-trachylobanes, ent-beyerane, and ent-atisane has been developed. The unified synthetic route involves the De Mayo reaction to rapidly generate the bicyclo[3.2.1]-octane moiety of ent-kaurane. The key reactions also include bioinspired nucleophilic cyclopropanation generating the [3.2.1.0^2,7]-tricyclic core of ent-trachylobane and regioselective cyclopropane fragmentation furnishing ent-beyerane and ent-atisane through the nucleophilic attack and protonation of the cyclopropane ring. This strategy enables the asymmetric total syntheses of six diterpenoids from the commercially available geraniol.     

Smart Magnetic and Fluorogenic Photosensitizer Nanoassemblies Enable Redox-Driven Disassembly for Photodynamic Therapy

Stimuli-responsive smart photosensitizer (PS) nanoassemblies that allow enhanced delivery and controlled release of PSs are promising for imaging-guided photodynamic therapy (PDT) of tumors. However, the lack of high-sensitivity and spatial-resolution signals and fast washout of released PSs from tumor tissues have impeded PDT efficacy in vivo. Herein, we report tumor targeting, redox-responsive magnetic and fluorogenic PS nanoassemblies ( NP-RGD ) synthesized via self-assembly of a cRGD- and disulfide-containing fluorogenic and paramagnetic small molecule ( 1-RGD ) for fluorescence/magnetic resonance bimodal imaging-guided tumor PDT. NP-RGD show high r₁ relaxivity but quenched fluorescence and PDT activity; disulfide reduction by glutathione (GSH) promotes efficient disassembly into a small-molecule probe ( 2-RGD ) and an organic PS (PPa-SH), which could further bind with intracellular albumin, allowing prolonged retention and cascade activation of fluorescence and PDT to ablate tumors.     

Diversified Excited-State Relaxation Pathways of Donor–Linker–Acceptor Dyads Controlled by a Bent-to-Planar Motion of the Donor

Herein, we introduce the cyclic 8π-electron (C8π) molecule N,N′-diaryl-dihydrodibenzo[a,c]phenazine ( DPAC ) as a dual-functional donor to establish a series of new donor–linker–acceptor (D–L–A) dyads DLA1 – DLA5 . The excited-state bent-to-planar dynamics of DPAC regulate the energy gap of the donor, while the acceptors A1 – A5 are endowed with different energy gaps and HOMO/LUMO levels. As a result, the rate and efficiency of the excited-state electron transfer vs. energy transfer can be finely harnessed, which is verified via steady-state spectroscopy and time-resolved emission measurements. This comprehensive approach demonstrates, for the first time, the manifold of excited-state properties governed by bifunctional donor-based D–L–A dyads, including bent-to-planar, photoinduced electron transfer (PET) from excited donor to acceptor (oxidative-PET), fluorescence resonance energy transfer (FRET), bent-to-planar followed by electron transfer (PFET), and PET from donor to excited acceptor (reductive-PET).