Incorporation of Stokes Shifting Dyes into a Si-Based Photovoltaic-Thermal System

Silicon photovoltaics (PVs) continue to improve through generational advancements, yet two main challenges remain. Photons with energies below the bandgap of the PV are not absorbed, leading to overheating and a decrease in device performance. Photons with energies above the bandgap of the PV undergo thermalization, damaging the device as well. To address these issues, we present a photovoltaic/thermal (PV/T) system which utilizes an infrared-absorbing thermal fluid containing Stokes shifting dyes. Together, the fluid and dyes allow for increased energy extraction from photons outside the bandgap of the PV. Through the use of a 3D curved architecture, we have shown that under solar simulation, when compared to a planar Si PV of the same performance, we are able to collect 98% more electrical energy over the course of a day. In addition to the increased electrical performance there is 35 W/m² of thermal energy generated which otherwise would damages the quality of the PV over time, a common issue with planar traditional PVs. Now, we plan to capture the thermalization of the high energy photons using Stokes shifting dyes and use it to increase overall device performance. We use multiple dyes, including Coumarin 6 and Coumarin 153, at varied concentrations under AM 1.5g standard conditions to study the angular response and thermal performance of the PV/T system. The data is supported by an optical ray tracing analysis using COMSOL software. Through preliminary results we see no major change in PV performance while there is a ~15% increase in thermal performance. With the combined collection of PV and thermal power, an effective efficiency of performance can be significantly above that of planar Si devices, while also being cost-effective and protecting the Si from damaging UV and overheating.