Observation of Coalescence Process of Silver Nanospheres During Shape Transformation to Nanoprisms

In this report, we observed the growth mechanism and the shape transformation from spherical nanoparticles (diameter ~6 nm) to triangular nanoprisms (bisector length ~100 nm). We used a simple direct chemical reduction method and provided evidences for the growth of silver nanoprisms via a coalescence process. Unlike previous reports, our method does not rely upon light, heat, or strong oxidant for the shape transformation. This transformation could be launched by fine-tuning the pH value of the silver colloidal solution. Based on our extensive examination using transmission electron microscopy, we propose a non-point initiated growth mechanism, which is a combination of coalescence and dissolution–recrystallization process during the growth of silver nanoprisms

Low temperature sintering of inkjet printed metal precursor inks for organic electronic applications

As a nascent technology that developed during the last decades from only printing text and graphics into an important scientific research tool for R&D, inkjet printers are nowadays used as a highly reproducible non-contact patterning tool. In contrast to non-digital patterning tools, inkjet printing represents an additive technique that requires only small amounts of functional materials and is therefore characterized as being a highly efficient materials patterning technique. In particular, inkjet printing of metal precursor materials has been used more and more during the last few years, in order to produce conductive features for plastic electronic applications. Here, we present our recent results in the sintering of inkjet printed metal nanoparticle dispersion on cost-effective polymer foils. In order to sinter the particles at speeds that are compatible with roll-to-roll speeds, we have used combinations of innovative sintering methods. Conductivity values between 40 and 60% were hereby obtained in a few seconds to minutes by using either photonic or plasma pre-sintering followed by microwave flash sintering. cop. 2013; Society for Imaging Science and Technology

Thermal Stable High-Efficiency Copper Screen Printed Back Contact Solar Cells

The high usage of silver in industrial solar cells may limit the growth of the solar industry. One solution is to replace Ag with copper. A screen printable Cu paste is used herein to metallize industrial interdigitated back contact (IBC) solar cells. A novel metallization structure is proposed for making solar cells. Cu paste is applied to replace the majority of the Ag used in IBC cells as busbars and fingers. Cu paste is evaluated for use as fingers, and solar cells are made to test conversion efficiency and reliability. The Cu paste achieves comparably low resistivity, and Cu paste printed cells demonstrate similar efficiency to Ag paste printed cells, with an average efficiency of 23%, and only 4.5 mg W−1 of Ag usage. Also, the solar cells are stable and no Cu in-diffusion is observed under damp heat (85 °C, 85% relative humidity) and thermal stress (200 °C) for 1000 h, respectively. All processes used in this study can be carried out with industrial equipment. These findings reveal a new application for Cu pastes and point to a new direction for reducing Ag utilization and cost.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Photovoltaic Materials and DevicesElectrical Sustainable Energ