An Abet Technologies Class ABB solar simulator was used as the light source for optical efficiency measurements. It was fitted with an AM1.5G filter to mimic the spectrum of actual sunlight. The height of the solar simulator above the sample was first calibrated using a reference solar cell of known efficiency coupled to a Keithley 2401 sourcemeter such that the intensity of light on the sample is 1000±10 W/m 2 . The LSC was placed on a custom-designed sample holder (Figure ) and a single edge of the LSC was placed against to the input port to an INS125 integrating sphere (225-1400 nm, International Light Technologies), that was connected that was connected to a spectroradiometer (SpectriLight ILT 950) via a fiber optic cable. All measurements were performed on a black absorptive background. where 𝑁 !"#$%& is the total number of edge-emitted photons summed over all edges of the LSC, 𝑁 !"#'() is the total number of photons absorbed by the LSC, and 𝑁 !"#*+ is the total number of photons incident on the top surface of the LSC. 𝑁 !"#$%& is obtained from the sum of the output power spectra, Pi(out)(λ), measured for each edge of the LSC (in W nm -1 ), where λ is the wavelength of light (in nm). Pin(λ) is the input power spectrum from the solar simulator incident on the top surface of the LSC (in W nm -1 ), h is Planck's constant (in J s), c is the speed of light (in m s -1 ), and A(λ) is the absorption spectrum of the LSC. The integrations are performed over the full AM1.5G solar spectrum (250-1050 nm). These spectra are in-built to pvTrace. Non-normalized spectra may also be obtained, which allows the absorbance and photoluminescence intensity to be modified based on the luminophore concentration.