Is Disorder Beneficial in Perovskite-Sensitized Solid-State Upconversion? The Role of DBP Doping in Rubrene

Solid-state bulk lead halide perovskite thin films have recently shown progress as triplet sensitizers in infrared-to-visible photon upconversion (UC) schemes. Common systems pair lead halide perovskites with a rubrene annihilator, doped with ∼1% dibenzotetraphenylperiflanthene (DBP), to prevent the efficiency limiting process of singlet fission. However, the interplay between rubrene and DBP has not been investigated in these spin-coated bilayer systems. Here, we investigate the UC photoluminescence intensity and the dynamics of the triplet sensitization process as a function of the DBP doping percentage of rubrene, finding that, as a whole, DBP does not significantly affect the UC intensity of the lead halide perovskite sensitized scheme. This indicates that, in the solution-processed devices reported here, rubrene disorder is sufficient to suppress unwanted singlet fission processes, removing the requirement of an annihilator/emitter system.