Alexander S. Bieber

Area of research

Electrical and Electronic Engineering · Materials Chemistry

Research interest

Research topics from publications: Triplet Sensitization by Lead Halide Perovskite Thin Films for Efficient Solid-State Photon Upconversion at Subsolar Fluxes; Influence of Triplet Diffusion on Lead Halide Perovskite-Sensitized Solid-State Upconversion; Green-to-Blue Triplet Fusion Upconversion Sensitized by Anisotropic CdSe Nanoplatelets; Is Disorder Beneficial in Perovskite-Sensitized Solid-State Upconversion? The Role of DBP Doping in Rubrene; Ultrafast Triplet Generation at the Lead Halide Perovskite/Rubrene Interface; Halide Heterogeneity Affects Local Charge Carrier Dynamics in Mixed-Ion Lead Perovskite Thin Films; Perovskite-sensitized upconversion bingo: Stoichiometry, composition, solvent, or temperature?; Understanding the effect of light and temperature on the optical properties and stability of mixed-ion halide perovskites; One‐Step Fabrication of Perovskite‐Based Upconversion Devices; Surface Doping Boosts Triplet Generation Yield in Perovskite‐Sensitized Upconversion. Representative work: The emerging field of lead halide perovskite-sensitized triplet–triplet annihilation (TTA) in rubrene shows great promise in upconversion applications. By rapidly transferring single charge carriers instead of bound triplet states, perovskites enable a high triplet population in rubrene, yielding low Ith values. In this contribution, we investigate the role of the triplet population on the upconverted emission. Interestingly, two independent rates of TTA can be observed, as well as a sharp drop in the visible emission intensity over several seconds. This effect can be attributed to the triplet-density-based diffusion length: (i) at low triplet populations slow diffusion-mediated TTA yields s Green-to-blue photon upconversion bears great potential in photocatalytic applications. Current hybrid inorganic–organic upconversion schemes commonly utilize spherical CdSe nanocrystals, but size polydispersity could influence efficiencies in future solid-state applications. In this contribution, we introduce anisotropic CdSe nanoplatelets as triplet sensitizers. Here, quantum confinement occurs in only one direction, erasing effects stemming from size polydispersity. Additionally, their high quantum yields, giant oscillator strengths, and large absorption cross sections could prove useful in a triplet sensitization scheme. We investigate the triplet energy transfer proce

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