LEGAL NOTICE This report was prepared as an account of Government sponsored work Neither tne United States, nor the Commission nor any person actmg on behalf of the Commission A Makes any warranty or representation expressed or impUed with respect to the accuracy, completeness, or usefulness of the information contained m this report or that the use of any information, apparatus, method, or process disclosed m this report may not infringe privately owned rights, or B. Assumes any liaDiltties with respect to the use of, or for damages resulting from the use of any mformation, apparatus, method, or process disclosed m this '•eport As used m the above "person acting on behalf of the Commission" includes any employee or contractor of the Commission or em,ployee of such contractor, to the extent that such emplojee or contractor of the Commission, or employee of such contractor prepares disseminates, or provides access to an> information pursuant to his employ ment or contract with the Commission, or his employment with such contractor

Optimization of charge generation in polymer blends is crucial for the fabrication of highly efficient polymer solar cells. While the impacts of the polymer chemical structure, energy alignment, and interface on charge generation have been well studied, not much is known about the impact of polymer aggregation on charge generation. Here, we studied the impact of aggregation on charge generation using transient absorption spectroscopy, neutron scattering, and atomic force microscopy. Our measurements indicate that the 1,8-diiodooctane additive can change the aggregation behavior of poly(benzodithiophene-alt-dithienyl difluorobenzotriazole (PBnDT-FTAZ) and phenyl-C61-butyric acid methyl ester (PCBM)polymer blends and impact the charge generation process. Our observations show that the charge generation can be optimized by tuning the aggregation in polymer blends, which can be beneficial for the design of highly efficient fullerene-based organic photovoltaic devices.

The freeze-dry process and its application in the general area of inorganic materials synthesis will be discussed. Details of the process will be given as well as its capabilities for producing ultrafine powders such as Pb–10 v/o MgO, WC, and W2C, ultrafine grained consolidated materials such as W–25 Re will be shown. Also, the application of the process for producing dispersion-strengthened systems such as Cu–ThO2 and Cu–W will be discussed.

No abstract

Organometal halides are promising materials for photovoltaic applications, offering tunable electronic levels, excellent charge transport, and simplicity of thin-film device fabrication. Two-dimensional (2D) perovskites have emerged as promising candidates over three-dimensional (3D) ones due to their interesting optical and electrical properties. However, maximizing the power conversion efficiency is a critical issue to improve the performance of these solar cells. In this work, we studied the photophysics of a two-dimensional (2D) perovskite (CH3NH3)2Pb(SCN)2I2 thin film using steady-state and time-resolved absorption and emission spectroscopy and compared it with the three-dimensional (3D) counterpart CH3NH3PbI3. We observed a higher bandgap and faster charge recombination in (CH3NH3)2Pb(SCN)2I2 compared to CH3NH3PbI3. This work provides an improved understanding of fundamental photophysical processes in perovskite structures and provides the guideline for the design, synthesis, and fabrication of solar cells.

Compression creep tests were performed on fully dense speci-I. Introduction mens of UC,.o,, UC,.,,, UCI.,,+4 wt% W, and Uo.gZro., Cl.01+4 wt% W. Steady-state creep rates were measured from 1400" to 1800°C in a vacuum of 1.33 x N/mZ (1 x torr) at stresses of 4.55 to 69.0 MN/m2 (660 to 10, OOO psi). The data for UCl,ol could best be fit by an expression of the form d = 17730s.024 exp (106.5/RT), where i. is the steady-state creep rate (h-l), m is the applied stress (MN/m2), and the creep activation energy is given in kcal/mol. The stress dependence for creep of UC decreased with decreasing temperature because of second-phase. precipitation; therefore, a unique creep activation energy could not be established for this U/C ratio. At all temperatures, the creep strength of UC,.,, exceeded that of UC,.,,. For example, at 1700°C steady-state creep rates for UC1.05 are =YI those for UC,,,,, but at 1400°C the creep rates are = 3 orders of magnitude less. At 1700"C, creep rates for UC alloys are =4 orders of magnitude lower than those for unalloyed UCl,ol.HE creep properties of 4 UC-based fuels were determined as T a function of stress from 1400" to 1800°C. The materials were(1) unalloyedUC,.,,, (2) unalloyedUC,,,,, (3) UC+4 wt% W, and Uranium carbide has the NaCl structure and a melting temperature of 2400"?50°C.1 Its homogeneity range, whose width varies with temperature, extends from =4.75 to4.90 wt% C for temperatures from 1300" to 1900"C, with the stoichiometric composition corresponding to 4.80 wt% C.z Below 4.8 wt% C, U forms in the microstructure after the UC cools to room temperature; above 4.8 wt% C, U2C, or UC2 forms in the microstructure.(4) Uo.g~o.iCi,ni+4 wt% W. Fig. 1. Microstructures of 100%-dense as-cast carbide specimens ( x 250). (A) UC,.,,, ( B ) UC,.,,, (C) UC1,,,+4 wt% W, and (0)Uo.gZro.lCl,ol+4 wt% W.138

No abstract

Ultrafeine WC‐ und W2C‐Pulver wurden durch rasche Gefriertrocknung einer Suspension von kolloidalem Graphit in ammoniakalischer Wolframatlösung, Reduktion des entstehenden WO3 mit H2 und Vakuumerhitzen des entstandenen W‐C‐Gemisches bei 1500°C erhalten.