Title :
Exciton Multiplication and Relaxation Dynamics in Quantum Dots: Applications to Ultra-High Efficiency Solar Photon Conversion
Author_Institution :
Center for Basic Sci., Nat. Renewable Energy Lab., Golden, CO
Abstract :
We show how semiconductor quantum dots may greatly increase photon conversion efficiencies by producing multiple excitons from a single photon. This is possible because quantization of energy levels in quantum dots enhances Auger processes, eliminates the requirement to conserve crystal momentum, and thus promotes multiple exciton generation, Quantum yields of 300% for exciton formation in PbSe, PbS, and PbTe quantum dots have been reported at photon energies about 4 times the HOMO-LUMO transition energy (QD bandgap), indicating the formation of 3 excitons/photon for all photoexcited quantum dots
Keywords :
Auger effect; IV-VI semiconductors; energy gap; excitons; lead compounds; semiconductor quantum dots; solar cells; Auger process; HOMO-LUMO transition energy; PbS; PbSe; PbTe; bandgap; crystal momentum; energy levels; exciton multiplication; multiple exciton generation; quantization; semiconductor quantum dots; ultra-high efficiency solar photon conversion; Costs; Electrons; Excitons; Hot carriers; Impact ionization; Kinetic energy; Photoconductivity; Photonic band gap; Photonic crystals; Quantum dots;
Conference_Titel :
Photovoltaic Energy Conversion, Conference Record of the 2006 IEEE 4th World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
1-4244-0017-1
Electronic_ISBN :
1-4244-0017-1
DOI :
10.1109/WCPEC.2006.279341
