The optical performance of LSCs was measured using a previously reported experimental setup (see Figure ). In brief, the LSC was illuminated with a solar simulator (Class ABB, AM1.5G, Abet Technologies) equipped with an AM1.5G filter. The LSC was supported on a bespoke 3D-printed sample holder, with one edge directly aligned with the port of an INS125 integrating sphere (225-1400 nm, International Light Technologies) to capture emitted photons.