Swift Heavy Ion (SHI) irradiation of semiconductor nanostructures is arapidly developing area of nanomaterials research which resultssignificant changes in structural and physical properties of such lowdimensional systems. The present study describes SHI irradiation effect onbare and silica (SiO2) coated semiconductor nanoparticles embedded ininsulating polymer (polyvinyl alcohol) and on a composite of semiconductornanoparticles and conductingpolymer(2-methoxy-5-(2-ethyl-hexyloxy)-pphenylene vinylene). The nanosemiconductor samples of PbS, CdS and ZnS were prepared following aninexpensive chemical route. Characterizations of the samples were carriedout with X-ray diffraction, optical absorption spectroscopy,photoluminescence and transmission electron microscopy. The UV–Visabsorption spectra reveal blue shift relative to bulk material inabsorption energy while PL spectra suggest that surface state and nearband edge emissions are dominating in case of bare and coated samplesrespectively. The samples were irradiated with 160 MeV Ni-ion beam withfluences in the range of 1e12 to 1e13 ions/cm2. The investigation afterSHI irradiation showed fluence dependent luminescence behavior and sizeenhancement of bare nanoparticles while reduction of particle size wasobserved in the composite system. However, coated samples exhibit betterstability upon SHI irradiation compared to the bare one.

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.