Showing papers by "Chang He published in 2014"
TL;DR: In this article, the design and synthesis of two solution-processable small molecules based on a conjugated backbone with a novel end-capped acceptor (oxo-alkylated nitrile) using octyl and hexyl chains attached to π-bridge, and octyl, pentyl and pentyl links attached to the acceptor is reported.
Abstract: Solution-processable small molecules are significant for producing high-performance bulk heterojunction organic solar cells (OSCs). Shortening alkyl chains, while ensuring proper miscibility with fullerene, enables modulation of molecular stacking, which is an effective method for improving device performance. Here, the design and synthesis of two solution-processable small molecules based on a conjugated backbone with a novel end-capped acceptor (oxo–alkylated nitrile) using octyl and hexyl chains attached to π–bridge, and octyl and pentyl chains attached to the acceptor is reported. Shortening the length of the widely used octyl chains improves self-assembly and device performance. Differential scanning calorimetry and grazing incidence X-ray diffraction results demonstrated that the molecule substituted by shorter chains shows tighter molecular stacking and higher crystallinity in the mixture with 6,6-phenyl-C71-butyric acid methyl ester (PC71BM) and that the power conversion efficiency (PCE) of the OSC is as high as 5.6% with an open circuit voltage (Voc) of 0.87 V, a current density (Jsc) of 9.94 mA cm-2, and an impressive filled factor (FF) of 65% in optimized devices. These findings provide valuable insights into the production of highly efficient solution-processable small molecules for OSCs.
82 citations
TL;DR: Two conjugated molecules with a [2,2]paracyclophane core were designed as non-fullerene electron acceptors for photovoltaic cells using as the donor a high power conversion efficiency for solution-processed OPVs.
40 citations
TL;DR: In this article, a solution-processed indacenodithiophene (IDT)-based small molecules with 1,3-indanedione (ID) as terminal acceptor units and 3,3′-hexyl-terthiophene as π-bridges, have been designed and synthesized for the application in organic field-effect transistors (OFETs) and organic solar cells (OSCs).
20 citations
TL;DR: Four solution-processable D-A-D structured organic molecules with diketopyrrolopyrrole (DPP) as acceptor unit and triphenylamine (TPA) or (4-hexyl)thieno [3,2-b]thiophene (HTT) as donor unit were designed and synthesized for the application as donor materials in solution- Processed organic solar cells (OSCs).
Abstract: Four solution-processable D-A-D structured organic molecules with diketopyrrolopyrrole (DPP) as acceptor unit and triphenylamine (TPA) or (4-hexyl)thieno [3,2-b]thiophene (HTT) as donor unit, DPP8-TPA, DPP8-TPA-OR, DPP6-HTT and DPP8-HTT, were designed and synthesized for the application as donor materials in solution-processed organic solar cells (OSCs) The molecules show broad absorption and relatively lower highest occupied molecular orbital energy levels Photovoltaic properties of the molecules were investigated by fabricating the bulk-heterojunction OSCs with the molecules as donor and PC71BM as acceptor Power conversion efficiency of the OSC based on DPP8-HTT reached 15% under the illumination of AM15, 100 mW cm−2
7 citations