In this work, granular Y2O3/Y3Al5O12(YAG) heterostructure thin films with 100-200 nm holes on surface were fabricated by depositing metal yttrium on c-plane sapphire and subsequent thermal anneal. Such Y2O3/YAG thin films are excellent matrix for luminescent materials based on rare earth. Based on this matrix, a Cr3+/(Pr3+/Yb3+) broadband down-converter was fabricated for improving the photovoltaic conversion efficiency of crystalline silicon solar cell (c-Si SC). Cr3+ was used to harvest the incident light and sensitize Pr3+/Yb3+ quantum cutting (QC) couple. QC down-conversion to Yb3+ infrared emission was realized in the region of 230 nm to 500 nm, which approaches the maximum bandwidth of QC down-conversion for c-Si SC. (C) 2016 Elsevier B.V. All rights reserved.