In-line Analytical Measurements for High-Throughput Manufacturing of Solar Cells, Enhancing Scalability of Next Generation Semiconductor Thin Film Stacks

A “stick and peel” removable electrochemical probe is used for solvent-free characterization of semiconductor films or optoelectronic devices and configured for use in situ and/or in operando. The invention may be used to analyze electronic materials such as a metal halide perovskite, an organic semiconductor, a nanocrystalline (quantum dot) thin film, metal oxides, a material blend or a device stack. The method may be used to analyze numerous characteristics, such as numbers of defects or defect density, stability, surface composition, band gap, physical structure, electroactivity, band bending, migration/diffusion process, and charging effects. This probe technology can be used in the manufacturing or analysis of thin film stacks to improve their performance and robustness.   

Background:
At present, the connection between the fundamental research to tailor and control chemical processes and the engineering of materials manufacturing is complicated, which often means performance of electronic materials or devices is less than desired. Some of the key shortcomings in conventional manufacturing processes of electronic devices or semiconductor films include, but are not limited to, in situ characterization (observe processes under conditions that replicate real-world and real-time conditions) and operando characterization (direct visualization and characterization of processes in real time under applied electric fields and flux conditions). Such methods that allow in situ and/or operando characterization of electronic devices and/or semiconductor materials during manufacturing and/or operation, respectively, will promote stronger ties between basic and applied research, and enhance rates of commercialization of viable technologies based on these optoelectronic materials. Besides knowledge, these techniques are essential analytical tools that can follow chemical reactions, physical processes, microstructural changes, and interfacial phenomena in real-world conditions.

For the high-throughput production of (opto)electronic devices (ex. solar cells), state-of-the-art multi-model characterization capabilities, as well as novel inline sensors, are needed to follow (electro)chemical (e.g., intermolecular interactions, interfacial processes, defects, etc.) and/or physical (drying, crystal formation, surface tension, etc.) processes during the roll-to-roll, blade coating, slot-die, ink-jet, and/or various forms of spray printing, manufacturing operation across length and time scales, or to understand device–transport layer interactions.

To date, progress in operando and in situ characterization capabilities for the inspection of manufacturing lines for optoelectronic devices such as solar cells based on organic semiconductors or organic-inorganic hybrid perovskites has been demonstrated using optical approaches, such as ellipsometry, absorbance/reflection/transmission, and/or (time-resolved) photoluminescence ((TR)PL) testing or incorporating processing with x-ray scattering/diffraction techniques. Unfortunately, there are many questions still not answered using these methods.

Applications:

• Semiconductor films and optoelectronics, including perovskite solar cells
• Film, material, material blend, or device stack
• Manufacturing, QC control
• Field QC, maintenance, trouble-shooting

Advantages:

• Simple "Stick and Peel" or incorporate in device
• Enables manufacturing and field quality control
• Improves and speed development of long-term stability of optoelectronic devices
• Numerous material characteristics may be measured under operando conditions
• Cost efficient