Quantum Dot-Induced Kinetic Bottleneck in Singlet Exciton Relaxation of Conjugated Polymer Aggregates
Abstract
Abstract We designed hybrid aggregate model systems with cascade energy alignment from conjugated polymers (CPs) to quantum dots (QDs) to investigate the effects of QDs on CP singlet (S1) excitons. Radiative recombination of S1 excitons occurs within 1 ps in the chlorinated CP/QD hybrid system, indicating an enhanced emissive pathway in an early-time regime. Optimized CP/QD phase separation induces end-on chain orientation and strengthens intrachain excitonic coupling, generating a vertical driving force for intrachain-mediated S1 dissociation along the z-axis. This force interacts with a lateral driving force in the xy-plane—stemming from the conduction-band offset—that biases CP electron density toward QD domains. The interplay between the two forces introduces a kinetic bottleneck that delays exciton relaxation and polaron formation, thereby increasing the probability of radiative recombination and the photoluminescence quantum yield. Our findings provide a strategy to regulate exciton decay pathways and improve CP-based device efficiency.
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Authors: Yeon Gyu Kim, Se Gyo Han, Minyoung Jeong, Taeyong Ha, Dong Hyeon Kim, Hyunjin Cho, Gui‐Min Kim, Sein Chung, Hyuk Gu Yun, Kyeong‐Hyeon Lee, Jun Sang Cho, Tae Rim Ko, Kyu Young Kim, Jieun Bang, Jaekak Yoo, Jungho Mun, Junsuk Rho, Seung Mi Lee, Jaehong Park, Young Jin Choi, Boseok Kang, Joon I. Jang, Doh C. Lee, Mun Seok Jeong, Sungjee Kim, Kilwon Cho, Dongki Lee
Institutions: University of Chicago, Ewha Womans University, Ewha Womans University Medical Center, Korea Advanced Institute of Science and Technology, Georgia Institute of Technology, University of Illinois Chicago, Chulalongkorn University, Sungkyunkwan University, Purdue University West Lafayette, Sogang University, Sejong University, Pohang University of Science and Technology, Hanyang University, Korea Research Institute of Standards and Science, Hanyang University Medical Center