OPTIMIZATION OF HYBRID COLLOIDAL QUANTUM DOTS GAAS SOLAR CELLS WITH HIGH ABSORPTION ENHANCEMENT

摘要

Because of the global warming effect and energy crisis, the usage of solar energy gets more and moreimportant in recent years. In particular, GaAs-based solar cells have been regarded as a promising candidate to providehigh power conversion efficiency because of their direct band gap and strong absorption over the entire visible part ofthe solar spectrum. In this work, we demonstrate a hybrid design of traditional GaAs-based solar cell combined withcolloidal quantum dots. Several photovoltaic parameters were enhanced, including the short circuit current density, fillfactor, and power conversion efficiency, which were measured under white light illumination similar to the solarspectrum. With anti-reflective feature at long wavelength and down-conversion at high energy photons, the quantumdot effectively enhance the overall power conversion efficiency by as high as 25% compared to traditional GaAs-baseddevice. The evolution of weighted reflectance as a function of the dilution factor of QDs has been investigated. Thedilution factors of quantum dots solution also have been optimized for single junction GaAs devices. We also use theEQE enhancement spectrum to further distinguish between the photon down-conversion and antireflection capabilityof QDs. Finally, we believe this technology shall be a great candidate for next generation of highly efficientphotovoltaic devices.