This work presents an equation concerning effective light doses (Dabs; J cm-2) absorbed by photosensitizer molecules that are involved directly in photochemical and photodynamic processes. These molecules are photostimulated by different polychromatic LED sources with distinct photonic properties. The inherent photosensitizer photobleaching process, source irradiation emission spectrum (wavelength range), light source power, irradiation time, and LED-methylene blue spectral overlap degree were the relevant parameters considered for Dabs. This was performed with an experimental system comprised of methylene blue and its photosensitization ability on substrate DFBF (1,3-diphenylisobenzofuran) photodegradation, starting from different polychromatic LED sources. We demonstrated that such factors significantly affect photosensitizer light absorption, thus influencing the efficiency of a specific photochemical process. This occurs due to the selection of non-optimal experimental conditions associated with less precision from photonic source measurements, and therefore, less control on the actual Dabs. Such insights are interestingly absent in various studies with regards to a plethora of systems.
Keywords:
polychromatic light sources; LED; effective absorbed light dose (Dabs); methylene blue; photosensitization
