Described are optical devices, such as photovoltaic modules that include features such as solar tracking, solar concentration, tandem cell arrangements, and thermal management to achieve high photovoltaic efficiency. The photovoltaic modules can be constructed using a variety of different materials and configurations or as a monoblock functionally graded structure to limit manufacturing, operational, and maintenance complexities while achieving high performance. The use of thermal management structures directly integrated into a photovoltaic cell can maintain such cells at desirable temperatures, which can be beneficial in optical concentrating configurations.