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The Human System: Then and Now

Speaker: Victor I. Klimov,Los Alamos National Laboratory,USA
When: 10:30, September 28, 2017 ~ 12:00, September 28, 2017
Where: Hall,Floor 2, School of Enviorment

Host: Li Liang Luminescent solar concentrators (LSCs) can serve as large-area sunlight collectors for terrestrial and space-based photovoltaics (PVs). Due to their high emission efficiencies and readily tuneable emission and absorption spectra, colloidal quantum dots (QDs) have emerged as promising LSC fluorophores, superseding dye molecules previously dominating the LSC field. An important advantage of the QDs over dye-based systems is a possibility to greatly reduce losses to re-absorption by displacing the emission band from the onset of strong optical absorption, the approach commonly referred to as “Stokes-shift engineering.” Spectral tunability of the QDs also facilitates the realization of stacked multi-layered LSCs wherein the enhanced performance is obtained through spectral splitting of incident sunlight, as in multi-junction PVs. This presentation will discuss several approaches to Stokes-shift engineering with II-VI and I-III-VI2 QDs and also describe the first example of a large-area (>200 cm2) tandem LSC based on two types of nearly reabsorption-free QDs spectrally-tuned for optimal solar-spectrum splitting. This prototype device exhibits a record-high optical quantum efficiency of more than 6% for sunlight illumination and solar-to-electrical power conversion efficiency of >3%. Due to their strong performance achievable with low-cost, solution-processible materials, QD-based LSC tandems can provide a viable pathway for greatly reducing the cost of solar electricity by complementing the existing PV technology with inexpensive, high-efficiency sunlight collectors deployable either as strongly absorbing LSC-PV modules or semi-transparent building-integrated solar windows.