Research

Research in the Bendavid Group focuses on innovating and advancing state-of-the-art solar energy technologies using theoretical and computational chemistry investigations. Computational quantum chemistry enables us to probe the physical, optical, electronic, and chemical properties of materials and molecules on an atomic level. Through these calculations, we better understand the relationship between structure and function and rationally design optimized materials and architectures for solar energy applications.

Our work seeks to improve the materials used in two fields of solar energy technologies – hybrid organic-inorganic photovoltaics and photocatalytic fuel production. Hybrid organic-inorganic solar cells are an attractive alternative to fully organic or inorganic solar cells, but current hybrid photovoltaics have thus far exhibited low efficiencies. Similarly, there is a lack of suitable stable, low cost semiconductors with the electronic properties required to be effective and efficient photocatalysts for reactions such as water splitting or CO2 reduction. The two projects described in greater detail below investigate new materials and architectures for these applications.

 

Photocatalytic Nanocomposites for Photovoltaics and Photocatalysis

Nanostructured device architectures incorporating graphene and reduced graphene oxide are highly promising low-dimensional structures with improved photocatalytic properties. In this project, we examine the structural, optical, electronic, and chemical properties of semiconductor-carbon nanocomposites for their application in photovoltaics and photocatalysis. This study seeks to improve the understanding of photovoltaic/photocatalytic enhancement through theory and computation, thereby enabling the architecture optimization.

nanocomposite

Schematic of charge transfer in a semiconductor-graphene nanocomposite for the photoreduction of CO2 with H2O

 

Interfacial Modification and Doping in Hybrid Photovoltaics

Hybrid organic-inorganic solar cells integrate the electrical, optical, and mechanical properties of organic and inorganic materials — specifically, the flexibility and low cost of the organic donor with the stability and electrical conductivity of the inorganic semiconductor acceptor. Unfortunately, even the most effective hybrid solar cells have operated with efficiencies  considerably lower than the organic solar cells they intend to improve upon.

Poor performance in nanostructured hybrid solar cells is often due to inefficient exciton separation and enhanced charge recombination in the interfacial region, among other factors. Some strategies to improve these interfacial properties include introducing interfacial molecular modifiers or changing the surface qualities via doping. This study seeks to explicate the individual and combined impacts of doping and interfacial modification on charge separation in a model hybrid solar cell interface.

Model of a ZnO/P3HT hybrid solar cell interface with a PCBA interfacial modifier

Model of a ZnO/P3HT hybrid solar cell interface with a PCBA interfacial modifier