Highly efficient inverted polymer solar cell by low temperature annealing of Cs2 C O3 interlayer

Hua Hsien Liao, Li Min Chen, Zheng Xu, Gang Li, Yang Yang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

493 Citations (Scopus)


We demonstrate a highly efficient inverted bulk heterojunction polymer solar cell based on regioregular poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester with a low temperature annealed interfacial buffer layer, cesium carbonate (Cs2 C O3). This approach improves the power conversion efficiency of the inverted cell from 2.3% to 4.2%, with short-circuit current of 11.17 mA cm2, open-circuit voltage of 0.59 V, and fill factor of 63% under AM1.5G 100 mW cm2 irradiation. This result is comparable to the previous regular structure device on the same system. Ultraviolet photoelectron spectroscopy shows that the work function of annealed Cs2 C O3 layer decreases from 3.45 to 3.06 eV. Further x-ray photoelectron spectroscopy results reveal that Cs2 C O3 can decompose into low work function, doped cesium oxide Cs2 O upon annealing, which is accountable for the work-function reduction and device efficiency improvement.
Original languageEnglish
Article number173303
JournalApplied Physics Letters
Issue number17
Publication statusPublished - 9 May 2008
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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