Photon Upconversion at Crystalline Organic–Organic Heterojunctions

Triplet transfer across a surface-anchored metal–organic-framework heterojunction is demonstrated by the observation of triplet–triplet annihilation photon ­upconversion in a sensitizer–emitter heterostructure. Upconversion thresholds under 1 mW cm−2 are achieved. In the broader context, the double-electron-exchange mechanism of triplet transfer indicates that the heterojunction quality is sufficient for electrons to move between layers in this solution-processed crystalline heterostructure. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.