Naughty Paul

We developed an unconventional route to produce uniform and intimately contacted semiconducting organic–inorganic nanocomposites for potential applications in thermoelectrics. By utilizing amphiphilic star-like PAA-b-PEDOT diblock copolymer as template, monodisperse PEDOT-functionalized lead telluride (PbTe) nanoparticles were crafted via the strong coordination interaction between PAA blocks of star-like PAA-b-PEDOT and the metal moieties of precursors (i.e., forming PEDOT–PbTe nanocomposites). As the inner PAA blocks are covalently connected to the outer PEDOT blocks, the PEDOT chains are intimately and permanently tethered on the PbTe nanoparticle surface, thereby affording a well-defined PEDOT/PbTe interface, which prevents the PbTe nanoparticles from aggregation, and more importantly promotes the long-term stability of PEDOT–PbTe nanocomposites. We envision that the template strategy is general and robust, and offers easy access to other conjugated polymer–inorganic semiconductor nanocomposites for use in a variety of applications.

A robust strategy to produce spherically shaped organic–inorganic nanocomposites composed of PbTe nanoparticles tethered with poly(3,4-ethylenedioxythiophene) (PEDOT) chains was developed by using amphiphilic star-like diblock copolymer PAA-b-PEDOT as template. The PbTe–PEDOT nanohybrids show long-term stability and hold promise for use in thermoelectrics.

Bed bugs have become a global epidemic and current detection tools are poorly suited for routine surveillance. Despite intense research on bed bug aggregation behavior and the aggregation pheromone, which could be used as a chemical lure, the complete composition of this pheromone has thus far proven elusive. Here, we report that the bed bug aggregation pheromone comprises five volatile components (dimethyl disulfide, dimethyl trisulfide, (E)-2-hexenal, (E)-2-octenal, 2-hexanone), which attract bed bugs to safe shelters, and one less-volatile component (histamine), which causes their arrestment upon contact. In infested premises, a blend of all six components is highly effective at luring bed bugs into traps. The trapping of juvenile and adult bed bugs, with or without recent blood meals, provides strong evidence that this unique pheromone bait could become an effective and inexpensive tool for bed bug detection and potentially their control.

Sleep tight! Bed bugs rely on chemical cues to locate and arrest in safe shelters. This aggregation pheromone comprises five volatile components (dimethyl disulfide and dimethyl trisulfide, (E)-2-hexenal, (E)-2-octenal, 2-hexanone) that attract bed bugs, and one less-volatile component (histamine) that causes their arrestment upon contact. This blend is highly effective at luring bed bugs into traps in infested premises.

Charming fluorine: This Essay examines the recent surge in late-stage fluorination reactions and outlines challenges that need to be overcome to increase the impact of modern fluorination methods on the synthesis of complex organofluorine compounds. It is outlined how an improved understanding of the bonding interactions of fluoride could lead to a new class of mild fluorinating reagents and a range of functional-group-tolerant reactions.

Absorbent layers of semiconductor quantum dots (QDs) are now used as material platforms for low-cost, high-performance solar cells. The semiconductor metal oxide nanoparticles as an acceptor layer have become an integral part of the next generation solar cell. To achieve sufficient electron transfer and subsequently high conversion efficiency in these solar cells, however, energy-level alignment and interfacial contact between the donor and the acceptor units are needed. Here, the layer-by-layer (LbL) technique is used to assemble ZnO nanoparticles (NPs), providing adequate PbS QD uptake to achieve greater interfacial contact compared with traditional sputtering methods. Electron injection at the PbS QD and ZnO NP interface is investigated using broadband transient absorption spectroscopy with 120 femtosecond temporal resolution. The results indicate that electron injection from photoexcited PbS QDs to ZnO NPs occurs on a time scale of a few hundred femtoseconds. This observation is supported by the interfacial electronic-energy alignment between the donor and acceptor moieties. Finally, due to the combination of large interfacial contact and ultrafast electron injection, this proposed platform of assembled thin films holds promise for a variety of solar cell architectures and other settings that principally rely on interfacial contact, such as photocatalysis.

Heterojunctions of PbS quantum dots (QDs) acting as sensitizers are coated on a thin layer of ZnO/PAA by the LbL technique to provide a larger interfacial contact compared with films made using the conventional sputtering method. Time-resolved experiments demonstrate that the excited carriers inject from PbS QDs into the ZnO conduction band within 160 fs.

Three organic or hybrid photovoltaic technologies are compared with respect to performance and stability under the harsh regime of concentrated light. Although all three technologies show surprisingly high (and linear) photocurrents, and better than expected stability, no golden apples are awarded.