• Research teams involved: Prabal K Maiti, Department of Physics; D. D. Sarma,  S. Ramasesha, Solid State & Structural Unit; U. Harbola, Department of Inorganic & Physical Chemistry; Abhishek K. Singh, Materials Reserach Centre.

Nanomaterials have profound implications in development of novel energy efficient solar cells.  Efficient operation of dye sensitized solar cell (DSSC) devices relies on minimization of interfacial recombination losses. A major factor responsible for the low efficiency of an organic dye-sensitized solar cell is the formation of dye aggregates. Both problems can be attenuated by adapting supra-molecular encapsulation strategies that accommodate the individual dye molecules and prevent self-aggregation. One such system is based on dendrimer based solar cell structures as well as using copolymer blend bulk heterojunctions. Use of various classes of nanoscale dendrimer in DSSC devicesshow interesting behavior such as efficient electron transfer, improved light harvesting efficiency and energy transfer properties.   We plan to use multi-scale modeling strategies to study the light harvesting properties of dendrimers and their application in DSSC devices. Software will be developed to build molecular models of a variety of conjugate dendrimer architectures such as phenyl-cored dendrimers, zinc-porphyrin dendrimer as well as ruthenium-cored dendrimer. Once the morphology of dendrimer aggregates is developed, we will study electronic properties, electron transport and energy transfer mechanisms in DSSC devices having dendrimer molecules. Our aim is to study structure property relationships in several dendritic architectures in the context of electron and hole mobilities. These studies will allow us to design appropriate dendrimer chemistry for creating improved dendrimer films to be used in solar devices. We plan to employ kinetic Monte Carlo as well as semi-classical Marcus theory to calculate the electron and hole mobilities in the dendrimer films as well as charge transport through the nanoscale polymer morphology to the electrodes.  Kinetic Monte Carlo approaches will utilize the charge transport parameters derived from ab intio and the structural information obtained from molecular dynamics to develop a suitable multiscale methodology for studying these systems.