Silver Diffusion in Organic Optoelectronic Devices: Deposition-Related Processes versus Secondary Ion Mass Spectrometry Analysis Artifacts

Abstract

The development of organic optoelectronic devices relies on controlling interfaces during thin-film deposition and requires an accurate characterization of the film composition at these interfaces. Dynamic secondary ion mass spectrometry (SIMS) is widely used to investigate multilayer thin-film structures. Routine analysis protocols are well established for classical semiconductor samples, but for organic or mixed metallic−organic samples the limitations of the technique are less well established. In the current work, low-energy dynamic SIMS is used on metal−organic multilayered model structures similar to those in organic optoelectronic devices to study the origin of diffusion of metal into the organic layer (e.g., irradiation-induced diffusion during SIMS analysis or during the deposition process). Samples contain silver and organic compounds sequentially deposited by thermal evaporation in vacuum onto a Si substrate. They are analyzed using a 250 eV to 1 keV Cs + primary ion beam. It is found that the mixing of silver into the organic layer depends on the impact energy and the conditions for sample preparation. This irradiation effect can be minimized by a back-side depth profiling approach, which was developed in this work. By applying this method, it is shown that some silver is likely to diffuse into the organic layers during the deposition process.

Pathway for recovery of photo-degraded polymer solar cells by post degradation thermal anneal

“…It is likely that the MoO x layer densifies and prevents diffusion of metal through it, preventing degradation of OSC with temperature treatment. This V oc recovery could not be achieved in PDA on p-i-n regular device structures shown in Fig 1A. This is because Ca/Al is in direct contact with the organic active matrix which may react and diffuse into the organic active layer, as reported in previous studies [35,36]. Such metal-organic interaction due to either thermal treatment of light soaking could result in drop of I sc and V oc simultaneously.…”

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and functional materials

“…In the latter paper, 160 the homogeneity of the crystals was determined using several techniques including EPMA (for the major element concentrations) whereas LA-ICP-MS and ID-ICP-MS were used for the U isotopic ratios. The ID-ICP-MS results were obtained following random selection of fragments of between 28 and 100 mg from the crystal followed by acid dissolution and spiking of enriched 235 U, 230 Th and 149 Sm. Accuracy was ensured through the analysis of the NIST SRM 612 glass.…”

“…Several high purity 233 U materials that were potentially useful as ID standards for safeguards and nuclear forensics applications were rescued from downblending. 162 The materials were analysed for the U isotope amount ratios ( 233 U/ 238 U, 234 U/ 238 U, 235 U/ 238 U and 236 U/ 238 U) using total evaporation-TIMS. Standard quadrupole-based ICP-MS was used for extra verication.…”

Improving the Thermal Stability of Top‐Emitting Organic Light‐Emitting Diodes by Modification of the Anode Interface

“…[26,27] Additionally, thermal diffusion of small molecules or metal ions can lead to degradation, for example, through the formation of nonradiative recombination centers. [28][29][30] Atomic layer deposition (ALD) can be operated at low working temperatures (down to 80 °C) when compared with other encapsulation technologies, such as chemical vapor deposition. [31] Indeed, ALD has been shown to offer TFE with suitable characteristics in many cases.…”