Lungwitz Dominique, Mansour Ahmed E, Zhang Yadong, Opitz Andreas, Barlow Stephen, Marder Seth R, Koch Norbert
Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, D-12489Berlin, Germany.
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-12489Berlin, Germany.
Chem Mater. 2023 Jan 4;35(2):672-681. doi: 10.1021/acs.chemmater.2c03262. eCollection 2023 Jan 24.
The ability to form multi-heterolayer (opto)electronic devices by solution processing of (molecularly doped) semiconducting polymer layers is of great interest since it can facilitate the fabrication of large-area and low-cost devices. However, the solution processing of multilayer devices poses a particular challenge with regard to dissolution of the first layer during the deposition of a second layer. Several approaches have been introduced to circumvent this problem for neat polymers, but suitable approaches for molecularly doped polymer semiconductors are much less well-developed. Here, we provide insights into two different mechanisms that can enhance the solvent resistance of solution-processed doped polymer layers while also retaining the dopants, one being the doping-induced pre-aggregation in solution and the other including the use of a photo-reactive agent that results in covalent cross-linking of the semiconductor and, perhaps in some cases, the dopant. For molecularly p-doped poly(3-hexylthiophene-2,5-diyl) and poly[2,5-bis(3-tetradecyl-thiophene-2-yl)thieno(3,2-)thiophene] layers, we find that the formation of polymer chain aggregates prior to the deposition from solution plays a major role in enhancing solvent resistance. However, this pre-aggregation limits inclusion of the cross-linking agent benzene-1,3,5-triyl tris(4-azido-2,3,5,6-tetrafluorobenzoate). We show that if pre-aggregation in solution is suppressed, high resistance of thin doped polymer layers to solvent can be achieved using the tris(azide). Moreover, the electrical conductivity can be largely retained by increasing the tris(azide) content in a doped polymer layer.
通过对（分子掺杂的）半导体聚合物层进行溶液处理来形成多异质层（光）电子器件的能力备受关注，因为这有助于制造大面积且低成本的器件。然而，多层器件的溶液处理在第二层沉积过程中对第一层的溶解提出了特殊挑战。对于纯聚合物，已经引入了几种方法来规避这个问题，但适用于分子掺杂聚合物半导体的方法却远未得到充分发展。在这里，我们深入探讨了两种不同的机制，它们可以提高溶液处理的掺杂聚合物层的耐溶剂性，同时还能保留掺杂剂，一种是溶液中掺杂诱导的预聚集，另一种是使用光反应剂，这会导致半导体以及在某些情况下掺杂剂发生共价交联。对于分子p型掺杂的聚（3 - 己基噻吩 - 2,5 - 二基）和聚[2,5 - 双（3 - 十四烷基噻吩 - 2 - 基）噻吩并（3,2 - ）噻吩]层，我们发现从溶液中沉积之前聚合物链聚集体的形成在提高耐溶剂性方面起主要作用。然而，这种预聚集限制了交联剂苯 - 1,3,5 - 三基三（4 - 叠氮基 - 2,3,5,6 - 四氟苯甲酸酯）的掺入。我们表明，如果抑制溶液中的预聚集，使用三叠氮化物可以实现薄掺杂聚合物层对溶剂的高抗性。此外，通过增加掺杂聚合物层中三叠氮化物的含量，可以在很大程度上保留电导率。
