A model for managing the product development process in house building

The performance of the product development process has a critical influence in the efficiency and duration of building projects, as well as on the quality of the final product. Despite its importance, relatively little attention has been given to the management of this process, if compared to production. The main objective of this paper is to present some results of a research project which aimed to devise a general model for managing the product development process in small sized companies involved in the development and construction of residential and commercial buildings. This model consists of a template for the product development process, which can be used by different companies as a basis to devise their own models for managing individual projects. The development of the model was based on case studies carried out in two companies from the South of Brazil and also on a benchmarking study

Triplet exciton generation in bulk-heterojunction solar cells based on endohedral fullerenes

Organic bulk-heterojunctions (BHJ) and solar cells containing the trimetallic nitride endohedral fullerene 1-[3-(2-ethyl)hexoxy carbonyl]propyl-1-phenyl-Lu3N@C80 (Lu3N@C80-PCBEH) show an open circuit voltage (VOC) 0.3 V higher than similar devices with [6,6]-phenyl-C[61]-butyric acid methyl ester (PC61BM). To fully exploit the potential of this acceptor molecule with respect to the power conversion efficiency (PCE) of solar cells, the short circuit current (JSC) should be improved to become competitive with the state of the art solar cells. Here, we address factors influencing the JSC in blends containing the high voltage absorber Lu3N@C80-PCBEH in view of both photogeneration but also transport and extraction of charge carriers. We apply optical, charge carrier extraction, morphology, and spin-sensitive techniques. In blends containing Lu3N@C80-PCBEH, we found 2 times weaker photoluminescence quenching, remainders of interchain excitons, and, most remarkably, triplet excitons formed on the polymer chain, which were absent in the reference P3HT:PC61BM blends. We show that electron back transfer to the triplet state along with the lower exciton dissociation yield due to intramolecular charge transfer in Lu3N@C80-PCBEH are responsible for the reduced photocurrent