Nanostructured surface for extended temperature operating range in concentrator photovoltaic modules

Abstract

Concentrator photovoltaic (CPV) systems that use silicone-on-glass Fresnel lenses as their primary optical element have reduced power output at high and low lens temperatures. We show that incorporating a nanostructured surface on the solar cell stabilizes best module performance over an extended operating temperature range. We model the optical properties of a self-organized monolayer of glass beads deposited on a polydimethylsiloxane (PDMS) encapsulated solar cell in a CPV sub-module. Our model combines transfer matrix method (TMM), rigorous coupled wave analysis (RCWA), and ray tracing to quickly and accurately simulate the system. We find the short-circuit current gain increases as the lens deviates from its designed working temperature for all bead sizes, and that 400 nm diameter beads submerged halfway into PMDS have the highest gain (up to 2.6%).

Microstructured antireflective encapsulant on concentrator solar cells

“…Figure 7 investigates the measured angle‐dependent current produced by the reference 3JSC, the commercial SiO x /3JSC, and beads/PDMS/3JSC with 1,000 nm‐diameter beads submerged 25% into the PDMS encapsulant. The histogram in Figure 7A displays the calculated angular distribution of irradiance on the cell in the simulated submodule represented in Figure 1A and previously shown in Forcade et al 24 Notice that most of the irradiance comes within an incident angle of 10–15°, as is expected for these square lenses. Figure 7B shows an increasing J sc with angle for both encapsulated cells but the opposite for the reference device.…”

“…These calculations provide the fraction of rays transmitted into the 3JSC at a wavelength interval of 300–1,800 nm, which we weight by the AM1.5D solar spectrum and the measured IQE (Figure 5) to calculate the J sc of the cell. Calculations of these wavelength‐dependent transmissions across the beads/PMDS interface are presented in Forcade et al 24 for several bead sizes.…”

“…Their study included a simulation suggesting that beads submerged halfway into the silicone could potentially provide greater gains. Simulations carried out by Forcade et al 24 showed that controlling the submergence of the beads in a layer of silicone can also improve the temperature dependency of a concentrator system and led to a J sc enhancement up to 2.6%, compared with devices without beads.…”