Panchromatic 鈥淒ye-Doped鈥?Polymer Solar Cells: From Femtosecond Energy Relays to Enhanced Photo-Response
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- 作者：Giulia Grancini ; R. Sai Santosh Kumar ; Margherita Maiuri ; Junfeng Fang ; Wilhelm T. S. Huck ; Marcelo J. P. Alcocer ; Guglielmo Lanzani ; Giulio Cerullo ; Annamaria Petrozza ; Henry J. Snaith
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2013
- 出版时间：February 7, 2013
- 年：2013
- 卷：4
- 期：3
- 页码：442-447
- 全文大小：420K
- 年卷期：v.4,no.3(February 7, 2013)
- ISSN：1948-7185
文摘
There has been phenomenal effort synthesizing new low-band gap polymer hole-conductors which absorb into the near-infrared (NIR), leading to >10% efficient all-organic solar cells. However, organic light absorbers have relatively narrow bandwidths, making it challenging to obtain panchromatic absorption in a single organic semiconductor. Here, we demonstrate that (poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b0]dithiophene)-alt-4,7-(2,1,3-benzothiadia-zole)] (PCPDTBT) can be 鈥減hoto-sensitized鈥?across the whole visible spectrum by 鈥渄oping鈥?with a visible absorbing dye, the (2,2,7,7-tetrakis(3-hexyl-5-(7-(4-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazol-4-yl)thiophen-2-yl)-9,9-spirobifluorene) (spiro-TBT). Through a comprehensive sub-12 femtosecond鈥搉anosecond spectroscopic study, we demonstrate that extremely efficient and fast energy transfer occurs from the photoexcited spiro-TBT to the PCPDTBT, and ultrafast charge injection happens when the system is interfaced with ZnO as a prototypal electron-acceptor compound. The visible photosensitization can be effectively exploited and gives panchromatic photoresponse in prototype polymer/oxide bilayer photovoltaic diodes. This concept can be successfully adopted for tuning and optimizing the light absorption and photoresponse in a broad range of polymeric and hybrid solar cells.