Recent Advances in Realizing Highly Aligned Organic Semiconductors by Solution‐Processing Approaches

Abstract

Solution‐processing approaches are widely used for controlling the aggregation structure of organic semiconductors because they are fast, efficient, and have strong practicability. Effective regulation of the aggregation structure of molecules to achieve highly ordered molecular stacking is key to realizing effective carrier transport and high‐performance devices. Numerous studies have achieved highly aligned organic semiconductors using different solution‐processing approaches. This article provides a detailed review of the prevalent solution‐processing technologies and emerging methods developed over the past few years for the alignment of organic semiconducting materials. These technologies and methods are classified according to the processing principle. This review focuses on the principles of different experimental techniques, improvements upon the conventional methods, and state‐of‐the‐art performance of resulting devices. In addition, a brief discussion of the characteristics and development prospects of various methods is presented.

Binary solvent engineering for small-molecular organic semiconductor crystallization

“…Another pathway is to apply external forces to align the crystal growth direction at the same time when the semiconductor undergoes crystallization. 94 This gives rise to miscellaneous alignment methods, such as air force navigation, 95,96 pinning confinement, 97,98 solution shearing, [99][100][101][102][103][104] blade coating, 105,106 zone casting, [107][108][109] and selective patterning. [110][111][112] Regardless of polymer mixing or external alignment, it is still imperative to control the various factors that critically influence semiconductor crystallization.…”

Polymorphism mediated by electric fields: a first principles study on organic/inorganic interfaces

“…Controlling the structure that forms at the interface is nontrivial, since most interfaces are usually grown out of thermodynamic equilibrium. [10][11][12] But even when they are grown in thermodynamic equilibrium, the typically available handlesbesides the choice of solvent 13,14 -are deposition pressure and temperature, which can only be varied over a limited range. This range is on one side limited by the thermal stability of the adsorbate molecules and on the other side by the technical capability of the experimental setup.…”

Polymorphism mediated by electric fields: A first principles study on organic/inorganic interfaces

“…Controlling the structure that forms at the interface is non-trivial, since most interfaces are usually grown out of thermodynamic equilibrium. [10][11][12] But even when they are grown in thermodynamic equilibrium, the typically available handles -besides the choice of solvent [13,14] -are deposition pressure and temperature, which can only be varied over a limited range. This range is on one side limited by the thermal stability of the adsorbate molecules and on the other side by the technical capability of the experimental setup.…”