Luminescence-guided and visibly transparent solar concentrators based on silicon quantum dots

Area of Science:

• Materials Science
• Renewable Energy
• Optoelectronics

Background:

• Luminescent solar concentrators (LSCs) offer a promising avenue for solar energy harvesting.
• Traditional LSCs often suffer from reabsorption losses and require multiple photovoltaic (PV) cells.
• Developing efficient and cost-effective LSCs for solar window applications remains a challenge.

Purpose of the Study:

• To demonstrate a novel tapered prism-shaped luminescent solar concentrator (LSC) for solar window applications.
• To utilize colloidal silicon quantum dots (SiQDs) as fluorophores for high visible transmission and reduced reabsorption.
• To enhance power conversion efficiency (PCE) by guiding luminescence to a single PV strip.

Main Methods:

• Fabrication of a tapered prism-shaped LSC.
• Incorporation of colloidal silicon quantum dots (SiQDs) with UV-selective absorption and large Stokes shift.
• Characterization of optical properties, including visible transmission and color rendering index (CRI).
• Performance evaluation of the SiQD-LSC as a solar window with a single Si PV strip.

Main Results:

• The SiQD-LSC achieved a power conversion efficiency (PCE) of 0.27% as a solar window.
• High average visible transmission (AVT) of 86% and a CRI of 94 were maintained.
• When the Si PV strip was front-facing, the overall solar window PCE increased to 1.18% by harvesting both direct sunlight and concentrated SiQD fluorescence.
• The PCE of the front-facing Si PV strip alone was boosted by 7% due to the guided luminescence.

Conclusions:

• The novel tapered prism-shaped LSC design effectively guides luminescence to a single PV strip, reducing cost and complexity.
• The use of SiQDs enables high optical performance, including excellent visible transmission and color rendering.
• This LSC technology demonstrates significant potential for efficient and aesthetically pleasing solar windows.