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Boosting Infrared Light Harvesting by Molecular Functionalization of Metal Oxide/Polymer Interfaces in Efficient Hybrid Solar Cells
Author(s) -
Grancini Giulia,
Santosh Kumar R. Sai,
Abrusci Agnese,
Yip HinLap,
Li ChangZhi,
Jen AlexK. Y.,
Lanzani Guglielmo,
Snaith Henry J.
Publication year - 2012
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201102360
Subject(s) - materials science , surface modification , polymer solar cell , organic solar cell , hybrid solar cell , polymer , energy conversion efficiency , nanotechnology , photovoltaics , oxide , nanocrystalline material , acceptor , band gap , optoelectronics , hybrid material , chemical engineering , photovoltaic system , composite material , ecology , physics , condensed matter physics , metallurgy , engineering , biology
Hybrid solar cells based on light absorbing semiconducting polymers infiltrated in nanocrystalline TiO 2 electrodes, have emerged as an attractive concept, combining benefits of both low material and processing costs with well controlled nano‐scale morphology. However, after over ten years of research effort, power conversion efficiencies remain around 0.5%. Here, a spectroscopic and device based investigation is presented, which leads to a new optimization route where by functionalization of the TiO 2 surface with a molecular electron acceptor promotes photoinduced electron transfer from a low‐band gap polymer(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) to the metal oxide. This boosts the infrared response and the power conversion efficiency to over 1%. As a further step, by “co‐functionalizing” the TiO 2 surface with the electron acceptor and an organic dye‐sensitizer, panchromatic spectral photoresponse is achieved in the visible to near‐IR region. This novel architecture at the heterojunction opens new material design possibilities and represents an exciting route forward for hybrid photovoltaics.