Zhao Xiaoming, Liu Tianjun, Liu Hongli, Wang Shirong, Li Xianggao, Zhang Yuteng, Hou Xueyan, Liu Zilu, Shi Wenda, Dennis T John S
Materials Research Institute and School of Physics and Astronomy , Queen Mary University of London , Mile End Road , E1 4NS London , U.K.
School of Chemical Engineering and Technology , Tianjin University , 300072 Tianjin , China.
ACS Appl Mater Interfaces. 2018 Dec 12;10(49):42715-42722. doi: 10.1021/acsami.8b12832. Epub 2018 Nov 28.
Organic semiconducting single crystals are ideal building blocks for organic field-effect transistors (OFETs) and organic photodetectors (OPDs) because they can potentially exhibit the best charge transport and photoelectric properties in organic materials. Nevertheless, it is usual for single-crystal OFETs to be built from one kind of organic material in which the dominant transport is either electron or hole; such OFETs show unipolar charge transport. Furthermore, single-crystal OPDs present high performance only in restricted regions because of the limited absorption of one-component single crystals. In an ideal situation, devices which comprise both electron- and hole-transporting single crystals with complementary absorptions, such as single-crystalline p-n heterojunctions (SCHJs), can permit broadband photoresponse and ambipolar charge transport. In this paper, a solution-processing crystallization strategy to prepare an SCHJ composed of C and 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-PEN) was shown. These SCHJs demonstrated ambipolar charge-transport characteristics in OFETs with a balanced performance of 2.9 cm V s for electron mobility and 2.7 cm V s for hole mobility. This demonstration is the first of single-crystal OFETs in which both electron and hole mobilities were over 2.5 cm V s. OPDs fabricated upon as-prepared SCHJs exhibited highly sensitive photoconductive properties ranging from ultraviolet to visible and further to near-infrared regions as a result of complementary absorption between C and TIPS-PEN, thereby attaining photoresponsivities that are among the highest reported values within the OPDs. This work would provide valuable references for developing novel SCHJ systems to achieve significant progress in high-performance ambipolar OFETs and broadband OPDs.
有机半导体单晶是有机场效应晶体管（OFET）和有机光电探测器（OPD）的理想构建材料，因为它们在有机材料中可能展现出最佳的电荷传输和光电特性。然而，单晶OFET通常由一种主导传输为电子或空穴的有机材料制成；这类OFET表现出单极性电荷传输。此外，由于单组分单晶的吸收有限，单晶OPD仅在受限区域呈现高性能。在理想情况下，由具有互补吸收的电子传输和空穴传输单晶组成的器件，如单晶p-n异质结（SCHJ），可以实现宽带光响应和双极性电荷传输。本文展示了一种溶液处理结晶策略，用于制备由C和6,13-双（三异丙基硅乙炔基）并五苯（TIPS-PEN）组成的SCHJ。这些SCHJ在OFET中展现出双极性电荷传输特性，电子迁移率为2.9 cm² V⁻¹ s⁻¹，空穴迁移率为2.7 cm² V⁻¹ s⁻¹，性能平衡。这是首次证明电子和空穴迁移率均超过2.5 cm² V⁻¹ s⁻¹的单晶OFET。基于所制备的SCHJ制造的OPD，由于C和TIPS-PEN之间的互补吸收，在从紫外到可见光再到近红外区域均表现出高灵敏度的光电导特性，从而获得了OPD中报道的最高光响应率之一。这项工作将为开发新型SCHJ系统提供有价值的参考，以在高性能双极性OFET和宽带OPD方面取得重大进展。
