Photoluminescence quenching at a ${\mathrm{p}\mathrm{o}\mathrm{l}\mathrm{y}\mathrm{t}\mathrm{h}\mathrm{i}\mathrm{o}\mathrm{p}\mathrm{h}\mathrm{e}\mathrm{n}\mathrm{e}/\mathrm{C}}_{60}$ heterojunction

Quenching of photoluminescence in a substituted polythiophene in the presence of a deposited ${\mathrm{C}}_{60}$ layer is studied by steady-state and time-resolved photoluminescence (PL). The steady-state PL is evaluated by considering the interference of the absorbed and emitted electro-optical field in the thin film coupled to exciton diffusion in the conjugated polymer. PL quenching occurs for excitons generated within 5 nm from the heterojunction. A blueshift of the polymer emission spectrum is observed when ${\mathrm{C}}_{60}$ is deposited on top of a polymer thin film. The blueshift is shown to be caused by PL quenching before the excitation is transferred to the lowest-energy sites.