Blended junctions are indispensable for organic solar cells; however, the fabrication of electron and hole transport routes in blended cells remains quite challenging. Herein, a lateral alternating multilayered junction using a high-mobility organic semiconductor is proposed and demonstrated. A total of 93% of the photogenerated electrons and holes are laterally collected over a long distance (0.14 mm). The exciton-collection efficiency reaches 75% in a lateral alternating multilayered junction with a layer thickness of 10 nm. A lateral organic alternating multilayered junction that completely collects both excitons and carriers can be an alternative blended junction for organic solar cells.

The organic semiconductor 2,7‐dioctyl[1]benzothieno[3,2‐b][1]benzothiophene (C8‐BTBT) is deposited on a single crystal (0001) Al2O3 (C‐sapphire) by a vacuum thermal evaporation, and effects of the layer thickness and preparation temperature on structural, morphological, optical, and electrical characteristics are investigated with X‐ray diffraction, atomic force microscopy observation, optical absorption measurement, and resistivity measurement with and without light irradiation. The C8‐BTBT layers possess the (001) out‐of‐plane orientation irrespective of the layer thickness and preparation temperature. The C8‐BTBT grains are growing up in direction parallel to the substrate surface keeping almost constant height, and the continuous layer is formed by the coalescence of the C8‐BTBT grains. The grain size of the continuous C8‐BTBT layer increases with raise in preparation temperature. The optical band gap energy could be estimated to be 3.32–3.35 eV regardless of the layer thickness and preparation temperature. The electrical resistivity decreases from 2.1 × 106 to 1.2 × 102 Ω cm with increase in the preparation temperature due to the increase in the grain size, and the light irradiation induce the drastical decrease to 42–28 Ω cm.

The organic molecule 2,7-dioctyl [1]benzothieno [3,2-b][1]benzothiophene (C 8 -BTBT) was deposited on quartz glass, ð1120Þ A-, (0001) C-, and ð1102Þ R-single-crystal Al 2 O 3 (sapphire), and (100)-, and (111)-single-crystal MgO substrates by vacuum thermal evaporation, and structural characterizations were carried out by X-ray diffraction analysis and atomic force microscopy (AFM) observation. The (001) out-of-plane orientation with a similar in-plane orientation was obtained irrespective of the substrate material and orientation, and its formation was governed by π-π-stacking-induced molecular ordering. The degree of orientation was reflected by the grain structure related to the substrate material. The growth model of the oriented C8-BTBT layer was speculated on the basis of experimental results.

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