::: B. REEJA JAYAN :::

Nobel Laureate Prof. Richard Smalley listed the biggest problems facing humanity as energy, water, food, environment, poverty, war, disease, education, democracy, and population. Through my teaching and research I hope to address the education, energy, and environment components on this list. Some of the research areas I have worked on include:

Interfacial charge transfer in organic-inorganic hybrid solar cells

Developing a fundamental understanding of photocurrent generation processes (e.g., exciton diffusion, interfacial charge transfer, and charge transport) at organic-inorganic heterojunctions is key for improving hybrid solar cell efficiency and stability. My research explores charge transfer processes at these interfaces by combining data from photovoltaic device performance tests under simulated AM 1.5G solar spectrum with fluorescence spectroscopy and surface characterization experiments using XPS, and conducting AFM.

High capacity lithium ion batteries with enhanced rate capability cells

The capacity of most cathode materials used in current lithium ion batteries is limited to < 200 mAh/g. This has generated interest in alternative low cost cathode materials which exhibit capacity values of ~ 250 mAh/g. However, these high capacity layered oxides suffer from low charge-discharge rate capability and huge irreversible capacity loss (50 – 100 mAh/g) in the first cycle. My work has shown that the electrochemical performances of these high capacity layered cathodes can be enhanced by coating their surfaces with organic and inorganic surface modifiers to generate a hybrid charge transfer interface. A patent on this process has been filed.

The role of electromagnetic radiation in thin film growth

Thin films of several industrially relevant materials like semiconductor oxides still require high temperature processing and/or expensive vacuum based deposition techniques to grow. High temperatures limit the choice of substrate materials on which these oxide films can be grown, as flexible plastic or polymeric substrates typically decompose above 250 ^oC. My work has demonstrated the use of electromagnetic radiation in the form of microwaves to catalyze growth of anatase TiO₂ thin films at temperatures as low as 150 ^oC), which is three times lower than conventional high temperature and gas phase deposition techniques. Numerical simulations of the film growth process, modeled using integral-form based Maxwell’s equation show strong correlation with experimental results. A patent on this process has been filed.

Structural and spectroscopic investigation of ZnO nanostructures for optoelectronic applications

I have worked on synthesis of porous single crystalline ZnO nanostructures (nanodisks, nano-pencils, nano-sponges) with unique morphology through facile wet chemical techniques. These ZnO structures were tailored to exhibit strong visible (blue-green, red, white) light emission on UV excitation. The larger surface area to volume ratio of these sponge-like nanostructures makes them attractive for applications like biochemical sensors and solar cells.