Upconversion-Triggered Charge Separation in Polymer Semiconductors

Yu Jin Jang, Eunah Kim, Seonghyeon Ahn, Kyungwha Chung, Jihyeon Kim, Heejun Kim, Huan Wang, Jiseok Lee, Dong Wook Kim, Dong Ha Kim

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Upconversion is a unique optical property that is driven by a sequential photon pumping and generation of higher energy photons in a consecutive manner. The efficiency improvement in photovoltaic devices can be achieved when upconverters are integrated since upconverters contribute to the generation of extra photons. Despite numerous experimental studies confirming the relationship, fundamental explanations for a real contribution of upconversion to photovoltaic efficiency are still in demand. In this respect, we suggest a new approach to visualize the upconversion event in terms of surface photovoltage (SPV) by virtue of Kelvin probe force microscopy (KPFM). One of the most conventional polymer semiconductors, poly(3-hexyl thiophene) (P3HT), is employed as a sensitizer to generate charge carriers by upconverted light. KPFM measurements reveal that the light upconversion enabled the formation of charge carriers in P3HT, resulting in large SPV of −54.9 mV. It confirms that the energy transfer from upconverters to P3HT can positively impact the device performance in organic solar cells (OSCs).

Original languageEnglish
Pages (from-to)364-369
Number of pages6
JournalJournal of Physical Chemistry Letters
Issue number2
StatePublished - 19 Jan 2017

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© 2016 American Chemical Society.


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