Cosolvent Approach for Solution-Processable Electronic Thin Films

Abstract

Low-temperature solution-processable electronic materials are of considerable interest for large-area, low-cost electronics, thermoelectrics, and photovoltaics. Using a soluble precursor and suitable solvent to formulate a semiconductor ink is essential for large-area fabrication of semiconductor thin films. To date, it has been shown that hydrazine can be used as a versatile solvent to process a wide range of inorganic semiconductors. However, hydrazine is highly toxic and not suitable for large-scale manufacturing. Here we report a binary mixed solvent of amine and thiol for effective dispersion and dissolution of a large number of inorganic semiconductors including Cu2S, Cu2Se, In2S3, In2Se3, CdS, SnSe, and others. The mixed solvent is significantly less toxic and safer than hydrazine, while at the same time offering the comparable capability of formulating diverse semiconductor ink with a concentration as high as >200 mg/mL. We further show that such ink material can be readily processed into high-performance semiconducting thin films (Cu2S and Cu2Se) with the highest room-temperature conductivity among solution-based materials. Furthermore, we show that complex semiconductor alloys with tunable band gaps, such as CuIn(S(x)Se(1-x))2 (0 ≤ x ≤ 1), can also be readily prepared by simply mixing Cu2S, Cu2Se, In2S3, and In2Se3 ink solutions in a proper ratio. Our study outlines a general strategy for the formulation of inorganic semiconductor ink for low-temperature processing of large-area electronic thin films on diverse substrates and can greatly impact diverse areas including flexible electronics, thermoelectrics, and photovoltaics.

High-performance thermoelectric silver selenide thin films cation exchanged from a copper selenide template

“…48,49,53 To form a thin-lm NC template, we adopted a method developed by Webber et al which demonstrated that bulk copper chalcogenides such as Cu 2 Se, Cu 2 Te and Cu 2 S can be dissolved in a thiol-amine solution mixture and be cast as thin lms on substrates. 45,51,54,55 However, bulk Ag 2 Se powder fails to do so at ambient conditions (see ESI, Fig. S3 †).…”

High-performance shape-engineerable thermoelectric painting

“…The Sb 2 Te 3 -based ChaM was synthesized by dissolving bulk elemental Sb and Te in a thiol–diamine mixture343536 instead of the widely used a N 2 H 4 solvent252627283738394041 due to its high-level toxicity. Sb 3 d 3/2 , Sb 3 d 5/2 and Te 3 d 5/2 peaks corresponding to metallic bonding peaks are identified in the X-ray photoelectron spectra (Supplementary Fig.…”

Review of Recent Progress in Antimony Chalcogenide‐Based Solar Cells: Materials and Devices

“…Hydrazine was usually used to directly dissolve metal chalcogenides to produce metal chalcogenide films. Considering the high toxicity of hydrazine, Brutchey et al developed a method using a binary mixed low‐toxicity solvent of amine and thiol for effective dispersion and direct dissolution of a large number of inorganic metal chalcogenide semiconductors . As shown in Figure b, 1,2‐ethanedithiol and 1,2‐ethylenediamine co‐solvent can easily dissolve chalcogenides, and thin films with good quality and high crystallinity can be achieved after solution deposition and annealing processes.…”