The absorption band edge is expected to be larger than E a due to potential defect hopping effects associated with the latter. Potential in-gap defect states in our samples, uncertainties in the sample geometry and absorption onset can offset the band gap estimation using electrical resistivity measurement by a few tens to hundreds of meV. Additionally, for materials with small gaps predicted by DFT-PBE calculations, exploring hybrid functionals is important as PBE method generally underestimates the band gap. To improve the accuracy of our band gap predictions for Ag 3 AuSe 2 and Ag 3 AuTe 2 , we utilized the hybrid functional mBJ. Indeed, the mBJ gaps corresponded well with the experimental values for both materials, which will be discussed in detail in the next section.