Analysis of absorption and thermal radiation performance of solar absorbers based on TiN, Nb2O5 and graphene

Abstract

This work proposes a multi-layer structured solar absorber based on TiN, metal oxide Nb2O5 and graphene. Simulations and calculations are based on finite-difference time-domain (FDTD) method. The average absorption efficiency of the structure is 94.41 % across the spectrum of 280–3000 nm, with absorption bandwidths of 2360 nm (for absorption efficiency exceeding 90 %) and 1819 nm (for absorption efficiency exceeding 95 %). Moreover, the weighted average absorption under AM 1.5 reaches 95.71 %, underscoring the exceptional absorption capabilities of the structure. This structure also has the property of polarization insensitivity. The absorption spectrum varies weakly with the polarization angle, and there is some deviation as the incident light increasing from 0 to 60°. However, the absorption efficiency at 60° is still 81.16 %. We further investigated the thermal radiation performance, discovering an efficiency exceeding 80 % within the range of 300–1400 K, and surpassing 90 % within 800–1400 K. These outstanding absorption and thermal radiation properties position the structure as highly versatile, with potential applications spanning solar energy harvesting and radiation-related fields.