A new method is described for the synthesis of high-quality CdSe nanocrystals (NCs) that eliminates the need for tri-octylphosphine oxide (TOPO). This new method is an adaptation of previously reported methods that use Cd salts as precursors for the CdSe NCs. High-boiling esters and ketones such as hexadecyl hexadecanoate (HH) and benzophenone (BP) appear to be excellent replacements for TOPO in this reaction. Compared with TOPO, HH offers a significant synthetic advantage as it slows the initial growth of the NC nuclei formed after injection of the Se precursor. This allows for superior control over particle size in the initial stages of the reaction, and thus permits facile production of high-quality CdSe NCs with very small diameters (<4 nm). Based upon the results presented here, a possible role is identified for TOPO in the CdSe NC synthesis. Understanding of the role of TOPO and other reaction components is crucial for continued progress in the synthesis of high-quality NCs.

A novel trichromophore amphiphilic dye N-methyl-2,4,6-tri-(4-dioctadecylamino)stilbazolium iodide (P 3 n) has been synthesized and successfully transferred on semiconducting transparent indium-tin oxide (ITO) electrodes by a Langmuir-Blodgett (LB) technique. Photocurrent generation was studied in a conventional photoelectrochemical cell. An action spectrum of the photocurrent generation is coincident with the absorption spectrum of the LB film-modified electrode, indicating that the dye aggregate in the LB film is responsible for the photocurrent. Some factors that may affect the observed photocurrent, such as the presence of O 2 , the concentrations of methyl viologen (MV 2+ ) and hydroquinone (H 2 Q), pH, and the bias voltage have been investigated. Models for the mechanism of light-induced electron transfer under different conditions are proposed.

The monolayer and multilayer films of an amphiphilic C 60 -EDTA (C 60 EA) and its tetramethyl ester (C 60 EM) were fabricated on semiconducting transparent ITO electrodes by the Langmuir-Blodgett (LB) technique. The photoelectric response of the modified electrodes was measured under various conditions to explore possible mechanisms of the electron transfer in this light harvesting and conversion system. The action spectrum of photocurrent implicates the excited C 60 EA or C 60 EM as the photoactive species in the photoinduced electron transfer process. Anodic or cathodic photocurrent could be observed depending on the composition and concentration of redox agents in the solution and/or bias voltage applied. These results suggest that electron flow in either direction is energetically possible in the present photoelectric chemical cell. When the pH in the solution was changed, the photocurrent of C 60 EA changed not only in its magnitude but also in its direction. Efficient photoinduced electron transfer was observed in the anodic direction. The quantum yields for the photocurrent generation of C 60 EM and C 60 EA monolayer-ITO system are 4.80% and 3.80% under favorable conditions.

Centrosymmetric molecules can exhibit strong second-harmonic generation (SHG) by Langmuir-Blodgett (LB) technique. The macroscopic nonlinearity χ (2) of the monolayer film reaches 245 pm V -1 for 4,4′-di{1-[1-(N,N′-dioctadecaneamino)phenylethylpyridinium bromide]octyl}dipyridinium bromide (PMV 8 ) and that for 4,4′-di{1-[1-(N,N′-dioctadecaneamino)phenylethylpyridinium bromide)]propyl}dipyridinium bromide (PMV 3 ) is 184 pm V -1 . Steady cathodic photocurrent is obtained upon excitation of the dyes incorporated into LB films deposited on an ITO electrode. The observed quantum yield of the photocurrent strongly depends on the applied electrode potential, concentration of the electron acceptor or donor, pH of the electrolyte, and the chemical structure of the dye congeners. The quantum yield reaches 4.73% for PMV 8 , while that for PMV 3 is 3.94%, under favorable conditions.

Summary We investigate the effects of thermally sensitive binder (TSB) on the temperature increase of lithium‐ion battery (LIB) coin cell subjected to severe mechanical abuse. The TSB is poly(vinylidenefluoride‐co‐hexafluoropropylene) (PVDF‐HFP), similar to conventional poly(vinylidenefluoride) (PVDF) binder but with a significant hexafluoropropylene (HFP) content. The testing data show that by using TSB, the peak temperature increase of nail‐penetrated LIB coin cell can be reduced by 20% to 40%, attributed to the softening of TSB that begins from ~80°C. The cycling performance of the LIB cells is also characterized. This research sheds light on the development of thermal‐runaway mitigation techniques.