title: Controlling light absorption in charge-separating core/shell semiconductor nanocrystals.
abstract: Semiconductor nanocrystals of different formulations have been extensively studied for use in thin-film photovoltaics. Materials used in such devices need to satisfy the stringent requirement of having large absorption cross sections. Hence, type-II semiconductor nanocrystals that are generally considered to be poor light absorbers have largely been ignored. In this article, we show that type-II semiconductor nanocrystals can be tailored to match the light-absorption abilities of other types of nanostructures as well as bulk semiconductors. We synthesize type-II ZnTe/CdS core/shell nanocrystals. This material is found to exhibit a tunable band gap as well as absorption cross sections that are comparable to CdTe. This result has significant implications for thin-film photovoltaics, where the use of type-II nanocrystals instead of pure semiconductors can improve charge separation while also providing a much needed handle to regulate device composition.
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science , Bangalore 560012, India.
authors.forename: Rekha
authors.initials: R
authors.lastname: Mahadevu
authors.forename: Aniruddha R
authors.initials: AR
authors.lastname: Yelameli
authors.forename: Bharati
authors.initials: B
authors.lastname: Panigrahy
authors.forename: Anshu
authors.initials: A
authors.lastname: Pandey