Organic photovoltaics (PVs) provide an attractive feature of easy and low-cost fabrication even for large area devices. However their energy conversion efficiency cannot compete with that of inorganic PVs partially because they are only able to strongly absorb 'visible' photons, while leaving about 50% of the solar energy in the near infrared (NIR) untapped. In this talk, I will present some of our most recent development in the NIR quantum dots (QDs) and their application in PVs. One example is about the controlled hybridization of NIR PbS QDs with carbon nanotubes (CNTs) and their further integration into poly(3-hexylthiophene), which is a hole-transporting polymer. The nanohybrid cells showed considerably enhanced power conversion efficiency, which is attributed to the significantly extended absorption in NIR by PbS QDs and the effectively enhanced charge transportation due to CNTs. Another example is about the higher quality PbS@CdS core@shell QDs, which showed either single emission from the core or intriguing double emissions from the core and shell, respectively.  The charge transfer behavior from these seemingly type-I QDs to other semiconductor materials  was discussed in terms of energy levels and spatial alignment of conduction- and valence-band edges, as well as time scales and ddominant factors were identified.On the other hand, plasmonic nanostructures have been recently explored for enhancing the efficiency of solar cells. Our recent work on the development of some interesting plasmonic nanomaterials, such as symmetric Ag nanorice and novel asymmetric Ag nanocarrot structures, which have strong resonances in the NIR regime, and their application in solar cells will also be briefly highlighted.Finally solution processed heterojunction inorganic solar cells based on TiO2 nanorods and NIR QDs will be briefly introduced.

Developing near infrared quantum dots and plasmonic nanostructures for solar cell applications

247th National Meeting (2014)

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