Umeyama, Tomokazu; Igarashi, Kensho; Sasada, Daiki; Ishida, Keiichi; Koganezawa, Tomoyuki; Ohtani, Shunsuke; Tanaka, Kazuo; Imahori, Hiroshi published the artcile< Efficient Exciton Diffusion in Micrometer-Sized Domains of Nanographene-Based Nonfullerene Acceptors with Long Exciton Lifetimes in Blend Films with Conjugated Polymer>, Name: 2-Ethylhexan-1-ol, the main research area is exciton diffusion nanographene nonfullerene acceptor blend film conjugated polymer; exciton diffusion; nonfullerene acceptors; organic photovoltaics; phase separation; side chain; singlet exciton lifetime; thienoazacoronene.
Phase-separated structures in photoactive layers composed of electron donors and acceptors in organic photovoltaics (OPVs) generally exert a profound impact on the device performance. Nonfullerene acceptors (NFAs) where a heteronanographene central core was furnished with branched alkoxy chains of different lengths, TACIC-EH, TACIC-BO, and TACIC-HD, were prepared to adjust the aggregation tendency and systematically probe the relations of film structures with photophys. and photovoltaic properties. The side-chain length showed negligible effects on the absorption properties and energy levels of TACICs. Regardless of the chain length, all TACIC films exhibited characteristically long singlet exciton lifetimes (1330-2330 ps) compared to those in solution (≤220 ps). Using a conjugated polymer donor, PBDB-T, the best OPV performance was achieved with TACIC-BO that contained medium-length chains, exhibiting a power conversion efficiency (PCE) of 9.92%. TACIC-HD with the longest chains showed deteriorated electron mobility due to the long insulating alkoxy groups. The PBDB-T:TACIC-HD-based device revealed a low charge collection efficiency and PCE (8.21%) relative to the PBDB-T:TACIC-BO-based device, but their film morphols. were analogous. TACIC-EH with the shortest chains showed low solubility and formed μm-sized large aggregates in the blend film with PBDB-T. Although the charge collection efficiency of PBDB-T:TACIC-EH was lower than that of PBDB-T:TACIC-BO, the efficiencies of exciton diffusion to the donor-acceptor interface were sufficiently high (>98%) owing to the elongated singlet exciton lifetime of TACIC-EH. The PCE of the PBDB-T:TACIC-EH-based device remained moderate (7.10%). Therefore, TACICs with the long singlet exciton lifetimes in the films provide a clear guideline for NFAs with low sensitivity of OPV device performance to the blend film structures, which is advantageous for large-scale OPV production with high reproducibility.
ACS Applied Materials & Interfaces published new progress about Atomic force microscopy. 104-76-7 belongs to class alcohols-buliding-blocks, and the molecular formula is C8H18O, Name: 2-Ethylhexan-1-ol.
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