Two-dimensional drift-diffusion simulation of organic solar cells

The aim of this master's thesis is to develop a two-dimensional drift-di usion model, which describes charge transport in organic solar cells. The main bene t of a two-dimensional model compared to a one-dimensional one is the inclusion of the nanoscale morphology of the active layer of a bulk heterojunction solar cell. The developed model was used to study recombination dynamics at the donor-acceptor interface. In some cases, it was possible to determine e ective parameters, which reproduce the results of the two-dimensional model in the one-dimensional case. A summary of the theory of charge transport in semiconductors was presented and discussed in the context of organic materials. Additionally, the normalization and discretization procedures required to nd a numerical solution to the charge transport problem were outlined. The charge transport problem was solved by implementing an iterative scheme called successive over-relaxation. The obtained solution is given as position-dependent electric potential, free charge carrier concentrations and current densities in the active layer. An interfacial layer, separating the pure phases, was introduced in order to describe charge dynamics occurring at the interface between the donor and acceptor. For simplicity, an e ective generation of free charge carriers in the interfacial layer was implemented. The pure phases simply act as transport layers for the photogenerated charges. Langevin recombination was assumed in the two-dimensional model and an analysis of the apparent recombination rate in the one-dimensional case is presented. The recombination rate in a two-dimensional model is seen to e ectively look like reduced Langevin recombination at open circuit. Replicating the J-U curves obtained in the two-dimensional model is, however, not possible by introducing a constant reduction factor in the Langevin recombination rate. The impact of an acceptor domain in the pure donor phase was investigated. Two cases were considered, one where the acceptor domain is isolated and another where it is connected to the bulk of the acceptor. A comparison to the case where no isolated domains exist was done in order to quantify the observed reduction in the photocurrent. The results show that all charges generated at the isolated domain are lost to recombination, but the domain does not have a major impact on charge transport. Trap-assisted recombination at interfacial trap states was investigated, as well as the surface dipole caused by the trapped charges. A theoretical expression for the ideality factor n_id as a function of generation was derived and shown to agree with simulation data. When the theoretical expression was fitted to simulation data, no interface dipole was observed.

Conscription Letter Envelope

An envelope from the Army and Navy Department "The International Committee of Young Men's Christian Associations (in the Field) General Office". The handwritten note on the front reads: "Capsule that decided someone's fate for conscription".

The effect of different phases of synchrony on the synchrony effect

Synchronization of behaviour between individuals has been found to result in a variety of prosocial outcomes. The role of endorphins in vigorous synchronous activities (Cohen, Ejsmond-Frey, Knight, & Dunbar, 2010) may underlie these effects as endorphins have been implicated in social bonding (Dunbar & Shultz, 2010). Although research on synchronous behaviour has noted that there are two dominant phases of synchrony: in-phase and anti-phase (Marsh, Richardson, Baron, & Schmidt, 2006), research on the effect of synchrony on endorphins has only incorporated in-phase synchrony. The current study examined whether both phases of synchrony would generate the synchrony effect. Twenty-two participants rowed under three counterbalanced conditions - alone, in-phase synchrony and anti-phase synchrony. Endorphin release, as measured via pain threshold, was assessed before and after each session. Change in pain threshold during the in-phase synchrony session was significantly higher than either of the other two conditions. These results suggest that the synchrony effect may be specific to just in-phase synchrony, and that social presence is not a viable explanation for the effect of synchrony on pain threshold

Envelope Addressed to Miss Julia Woodruff

Envelope addressed to Miss Julia Woodruff of St. Davids. Postmarks include: Suspension Bridge, N.Y., May 20, 1857; Clifton, May 20, 1857 and St. Davids, May 21, 1857.

Envelope Addressed to Noah Phelps, Lincoln Paper Mill Co.

Envelope addressed to Noah Phelps, Lincoln Paper Mill Co. with no postmarks, Merritton [In about 1877 Noah Phelps, Samuel Woodruff, Partrick Joseph Larkin and John Conlon were involved in the founding of a paper mill with Sylvester Neelon], n.d.

Envelope sent to Mr. Welland D. Woodruff at Thomas Cooks and Sons, Columbo, Indiana

Envelope postmarked Indo-Ceylon, special flight X’mas 1936, Bombay, Jan. 1937 and Thomas Cook and Son, Jan. 2, 1937. The letter is addressed to Mr. Welland D. Woodruff at Thomas Cook and Son, Columbo, India. This is crossed out and sent on to Royal Trust Co. 3 St. James St., London, England. This is crossed out and finally sent to the Mayfair Hotel, London, England, 1936-1937.

Letter and envelope addressed to Mr. Samuel D. Woodruff of St. Catharines

Letter and envelope addressed to Mr. Samuel D. Woodruff of St. Catharines. The envelope is postmarked St. Catharines, Dec. 31, 1887, Port Robinson, Dec. 31, 1887 and Welland, Dec. 31, 1887. The letter to S.D. Woodruff from Calvin Cudney and it says that he has enclosed $35 in interest, Dec. 29, 1887.

Application for Loan, Mortgage Loan Envelope, and Abstract of Title

Atkins, Sarah A. and Carlisle A. Gardner includes: Application for Loan, July 26, 1884; Mortgage Loan Envelope no. 255 for July 1, 1884 – July 1, 1889 and Abstract of Title, August 28, 1884.

Cogswell, Maria, includes: Application for loan on Real Estate, Insurance Policy, Mortgage Loan Envelope

Cogswell, Maria, includes: Application for loan on Real Estate, Feb. 20, 1882; Insurance Policy no. 2199780 from the Royal Insurance Company of Liverpool, March 17, 1887 and Mortgage Loan Envelope for mortgage no. 1535 from March 1, 1882 – March 1, 1887.

Crew, Isaac M., includes: Application for Loan, Mortgage Loan Envelope, and Abstract of Title

Crew, Isaac M., includes: Application for Loan, March 10, 1885; Mortgage Loan Envelope no. 679 for Jan. 1, 1885 – Jan. 1, 1890 and Abstract of Title, April 13, 1885.