Unidirectional and crystalline organic semiconductor microwire arrays by solvent vapor annealing with PMMA as the assisting layer
Unidirectional and crystalline organic microwire arrays hold great potential for transistors, logic circuits and optoelectronic devices. A fundamental step towards a practical implementation is their effective production. However, unidirectional alignment and high crystallinity of the organic microwire arrays are challenging to achieve by most of the current methods, either because of the complex procedures or the incapability of unidirectional alignment. Herein, we reported a simple yet efficient method, i.e., the polymer assisted solvent vapor annealing (PASVA) approach, for the production of unidirectional and crystalline organic semiconductor microwire arrays. A tilted substrate and a PMMA assisting layer were introduced to guide the growth direction of the microwire arrays and to increase the fluidity of the organic semiconductor molecules during the PASVA process. The charge carrier mobility was increased three times as compared with microwires produced by the traditional SVA method without the assisting polymer layer.