Thin films of a conjugated polymer Poly [2-methoxy-5-(3’,7’-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) were prepared from chloroform, 1,2dichlorobenzene and toluene solutions by spin coating technique on quartz substrates. Absorption and photoluminescence (PL) spectra of the polymer thin films prepared from different solvents were measured. The UV-vis absorption and PL spectra of MDMO-...

This paper analyses the portfolio problem of an investor maximizing the expected exponential utility of his terminal real wealth. The investor must cope with both a set of stochastic investment opportunities and a set of background risks. If the market is complete we are able to find an exact solution. If the market is incomplete, we suggest an approximated general solution. Contrary to other e...

I prove that, in models with complementarities, some non-monotone comparative statics must select unstable equilibria; and, under additional regularity conditions, that monotone comparative statics selects stable equilibria. JEL Classification. C61, C62, C72, C73. Discussions with my advisers, Ilya Segal and Chris Shannon, were very important for this work. I am very grateful for their help. I ...

The paper analyzes how social barriers to communication affect economy-wide productivity and factor accumulation. Using a dynamic model of an economy that includes a reproducible capital stock (physical or human) and effective labor, a negative relationship is shown to exist between social barriers to communication and total factor productivity (TFP), per capita consumption and reproducible cap...

This article investigates common economic consequences of population aging and economic integration for agglomeration processes. We introduce demography into the New Economic Geography by generalizing the constructed capital approach to account for changes in the age structure of the population. Interestingly, the level of trade costs triggering catastrophic agglomeration is rather sensitive to...

This paper presents a spectroscopic study on doping of Vanadyl pathalocyanine (VOPc) by [6,6]-phenyl C61 butyric acid methyl ester (PCBM). The films are characterized by UV/Vis/NIR spectroscopy. A drastic increase in the absorption coefficient has been observed with increasing dopant concentration. Optical properties of VOPc:PCBM films deposited by spin coating technique were studied in detail....

We consider an environment of a fixed size that can be converted to another use. This conversion can be made in steps, but it is irreversible. The future benefits (per unit) from the original use, and from the alternative use, follow a diffusion process. For a fairly general case, we show that the value function must be the unique (viscosity) solution to the associated Hamilton-Jacobi-Bellman e...

This paper is concerned with the relationship between the discount rate and the nature of long-run behavior in dynamic optimization models. The theory is developed under two conditions. The first is history independence, which rules out multiple limit sets. The second is a condition that avoids the reversion to a stable steady state, as the discount factor is lowered, once cycles have emerged. ...

We have investigated the performance characteristics of bulk-heterojunction polymer solar cells based on poly(3-hexylthiophene-2,5-diyl) and [6,6]-phenyl C61 butyric acid methyl ester by adding 1,8-octanedithiol as a processing agent in an active layer. The effects of the additive, 1,8-octanedithiol, on the device performance parameter characteristics have been discussed. The current density-vo...

This paper develops recursive methods to study optimal and time consistent policy in dynamic models. We analyze a version of Calvo's 1978 monetary model and show that its time consistent outcomes can be completely characterized as the largest fixed point of either of two operators. Recursive application of these operators provides a computing algorithm which always converges to the set of time ...