Solution-grown organic single-crystalline p-n junctions with ambipolar charge transport

Two-dimensional MoS2-assisted immediate aggregation of poly-3-hexylthiophene with high mobility

Immediate crystallization of P3HT has been induced by two-dimensional MoS₂ nanosheets under ultrasonication, which contributes to an obvious enhancement in mobility.

Cyano-substituted oligo(p-phenylene vinylene) single-crystal with balanced hole and electron injection and transport for ambipolar field-effect transistors

High performance symmetric OFETs (organic field-effect transistors) made with strong green fluorescent single-crystals demonstrated well-balanced mobilities of around 0.5 cm² V⁻¹ s⁻¹.

Solution-grown organic single-crystalline donor-acceptor heterojunctions for photovoltaics

Organic single crystals are ideal candidates for high-performance photovoltaics due to their high charge mobility and long exciton diffusion length; however, they have not been largely considered for photovoltaics due to the practical difficulty in making a heterojunction between donor and acceptor single crystals. Here, we demonstrate that extended single-crystalline heterojunctions with a consistent donor-top and acceptor-bottom structure throughout the substrate can be simply obtained from a mixed solution of C60 (acceptor) and 3,6-bis(5-(4-n-butylphenyl)thiophene-2-yl)-2,5-bis(2-ethylhexyl)pyrrolo[3,4-c]pyrrole-1,4-dione (donor). 46 photovoltaic devices were studied with the power conversion efficiency of (0.255±0.095)% under 1 sun, which is significantly higher than the previously reported value for a vapor-grown organic single-crystalline donor-acceptor heterojunction (0.007%). As such, this work opens a practical avenue for the study of organic photovoltaics based on single crystals.

Volatilize-controlled oriented growth of the single-crystal layer for organic field-effect transistors

We demonstrate a solution method of volatilize-controlled oriented growth (VOG) to fabricate aligned single crystals of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) on a Si/SiO2 substrate. Through controlling the evaporation rate of the solvent, large-area-aligned single-crystal layers can be achieved on several substrates at the same time, covering over 90% on 2 × 1 cm substrates. The method provides a low-cost, maneuverable technology, which has potential to be used in batch production. We find that the atmosphere of the solvent with high dissolving capacity is in favor of aligned single-crystal growth. Besides, the growth mechanism of the VOG method is investigated in this paper. Top-contact organic field-effect transistors based on the single crystals of TIPS pentacene are achieved on a Si/SiO2 substrate. The optimal device exhibits a field-effect mobility of 0.42 cm(2) V(-1) s(-1) and an on/off current ratio of 10(5). Our research indicates that the VOG method is promising in single-crystal growth on a Si/SiO2 substrate for commercial production.

Solution-grown single-crystalline microwires of a molecular semiconductor with improved charge transport properties

Preparation and structural analysis of highly ordered single crystalline wires of a diketopyrrolopyrrole (DPP) molecular semiconductor grown through a solution process are reported, and the static/dynamic electrical response of an organic electronic device using the DPP semiconductor has been analyzed.