In the last decade there has been increased emphasis on crystallizingpolymers or assembling small organic molecules to form well orderedorganic films. There are many polymers which can not be crystallized bystandard methods that protein crystallographers use. We have demonstrateda technique that has possibility to be used as a tool to crystallizecertain molecules. On the other hand, the development of the field oforganic electronics has benefited from the unique set of characteristicsoffered by π-conjugated oligmoers and polymers. These molecules showsemiconducting properties. Remarkable progresses have been made on thedevelopment of the devices based on organic semiconducting (OSE)materials due to the unique capabilities offered by the tunability andsynthesis of organic molecules together with the possibility of low-costand large area fabrication at moderate substrate temperature. Some fieldsof applications are organic thin-film transistors (OTFTs), organiclight-emitting diodes (OLEDs), photovoltaic cells etc. Though themobility of the OSE thin films are relatively lower than that ofinorganic counterparts like Si or Ge but highly ordered films canimprove mobility and demonstrated performance of organic thin filmtransistors (OTFT) based on these ordered films suggest that they arecompetitive candidates for replacing the existing or novel thin filmtransistors applications requiring large-area coverage, structuralflexibility, low temperature processing. In this talk I am going todiscuss how to assemble OSE molecules to grow well ordered organicfilms which show improved device properties. Nevertheless, there are manyopen questions and challenges related to the understanding the growthmechanisms and physical principles of molecular ordering in the organicfilms.

Thermoelectrics (TE) are solid state systems which convert heat toelectricity or do active cooling by passing a current through it. They canbe used for power generation or cooling devices. Although TE have been around for more than 100 years they are not widely used because of theirlow efficiency. The efficiency of a TE is determined by a dimensionlessfactor ZT called the figure of merit which depends on both electronic andphononic properties of the solid. Due to competing physical effects it hasbeen very difficult to make ZT much larger than 1. However, in recentyears several theoretical ideas (electron crystal phonon glass, transportin reduced dimensionality, dissipation-less energy transport throughenergy filtering etc ) have been proposed to increase ZT beyond 1. Severalof these ideas have been implemented in designing novel materials and someof these show a ZT value ~2. These concepts and how they operate in thesematerials will be discussed. Conditions for dissipation-less energytransport which occurs in a perfect thermoelectric will be explained.Attempts to design such materials will be described.* Work partly supported by a ONR-MURI grant.

Physicists and chemists have been interested in devising materials and methods to induce ferromagentic order in several oxides. Such studies provide an understanding of the fundamental mechanisms involved. In addition, these materials are candidates for potential applications in magnetic memories, sensors etc. Typical examples are ferrites and garnets. However there are other oxides which show novel properties. In this talk, I will describe three such classes of materials – double layer spin cluster glass manganites that exhibit a resistance drop of 1 million in moderate fields but at low temperatures, frustrated pyrochlores where ferromagentic order is induced by proper selection of substitution and undoped indium oxide in which charge carriers seem to be spin polarized.