Surface Equilibration Mechanism Controls the Stability of a Model Co-deposited Glass Mixture of Organic Semiconductors

Abstract

While previous work has identified the conditions for preparing ultrastable single-component organic glasses by physical vapor deposition (PVD), little is known about the stability of co-deposited mixtures. Here, we prepared binary PVD glasses of organic semiconductors, TPD (N,N-Bis(3-methylphenyl)-N,N-diphenylbenzidine) and m-MTDATA (4,4,4-Tris[phenyl(m-tolyl)amino]triphenylamine), with 50:50 mass concentration over a wide range of substrate temperatures (Tsub). The enthalpy and kinetic stability are evaluated with differential scanning calorimetry and spectroscopic ellipsometry. Binary organic semiconductor glasses with exceptional thermodynamic and kinetic stability comparable to the most stable single-component organic glasses are obtained when deposited at Tsub=0.78-0.90Tg (where Tg is the conventional glass transition temperature). When deposited at 0.94Tg, the enthalpy of m-MTDATA/TPD glass equals that expected for the equilibrium liquid at that temperature. Thus, the surface equilibration mechanism previously advanced for single-component PVD glasses is also applicable for these co-deposited glasses. These results provide an avenue for designing high-performance organic electronic devices.

23 pages, 5 figures, 47 references, Supporting information including 5 figures

References in corpus (6)

• On the surface of glasses
• Two-Level Systems and Boson Peak Remain Stable in 110-Million-Year-Old Amber Glass
• Macroscopic Facilitation of Glassy Relaxation Kinetics: Ultra Stable Glass Films with Front-Like Thermal Response
• Origin of ultrastability in vapor-deposited glasses
• Highly Stable Glasses of cis-Decalin and cis/trans-Decalin Mixtures
• Increased stability of CuZrAl metallic glasses prepared by physical vapor deposition

Cited by in corpus (5)

• Generic behavior of ultrastability and anisotropic molecular packing in co-deposited organic semiconductor glass mixtures
• Achieving Different Stoichiometries and Morphologies in Vapor Phase Deposition of Inorganic Halide Perovskites: Single or Dual Precursor Sources?
• High density two-component glasses of organic semiconductors prepared by physical vapor deposition
• Physical aging of glasses of an organic semiconductor
• Initial Stages of Rejuvenation of Vapor-Deposited Glasses during Isothermal Annealing: Contrast Between Experiment and Simulation