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Exciton Charge Separation at a Donor–Acceptor Junction

Interactive 3D model of exciton diffusion and Onsager–Braun dissociation at an organic solar cell's donor–acceptor heterojunction: tune field, temperature and charge-transfer-state separation and watch excitons split into free electrons and holes, or recombine.

Materials Science3DAdvanced60 FPS📱 Mobile-adapted⇄ 2D version

In an excitonic (organic) solar cell, absorbed light first produces a neutral, Coulomb-bound exciton rather than free charge — the cell only makes current if that exciton reaches a donor–acceptor interface before decaying, then dissociates into a free electron and hole instead of recombining. This simulation renders both stages in real 3D: excitons perform a physically scaled random walk through the donor layer with a tunable diffusion length, and at the interface their fate is decided by the Onsager–Braun model of field- and temperature-assisted charge-transfer-state dissociation. Adjust the applied field, temperature, and charge-transfer separation to see the dissociation probability, internal quantum efficiency, and relative photocurrent respond exactly as they do in real bulk-heterojunction photovoltaic materials.

⚙ Under the hood

Watch photogenerated excitons random-walk through a donor layer toward a donor–acceptor heterojunction, where the Onsager–Braun model decides whether each one splits into a free electron–hole pair or recombines, and see how field, temperature and charge-transfer separation control an organic solar cell's efficiency.

excitonsorganic photovoltaicscharge separationOnsager-Braunheterojunctionsolar cells

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install