Band Gap Engineering

Research and Practice of Colloids in Band Gap Engineering

Monodisperse colloidal particles can form colloidal crystals under suitable conditions. The micro-nano structure of colloidal crystals endows them with unique optical properties. Compared with other types of photonic crystals, colloidal photonic crystals have the advantages of simple preparation process, low cost, and easy realization of various modifications and functionalizations. These excellent properties make colloidal photonic crystals widely used.

Common colloidal crystals include SiO₂, polystyrene latex spheres, ZnO colloidal spheres, SiO₂-TiO₂, ZnS-SiO₂, PS-ZnS and other core-shell particles, iron-cobalt oxide particles, etc. Some gel materials can also be used to construct narrow colloidal crystals. For example, soft thermosensitive microhydrogel particles can be transformed into color-tunable colloidal crystals through volume transformation. The band gap of colloidal crystals can be controlled by surface chemical modification. It was found that the colloidal PbS modified by thiol ligand exchange showed a change in the band gap.

Fig.1 One, two and three-dimensional photonic band-gap structures.^[2]

Fig.2 Surface Chemistry Control of Colloidal Quantum Dot.^[3]

Alfa Chemistry can provide colloidal crystal-like photonic bandgap materials for bandgap engineering. We have strong R&D capabilities and can utilize a variety of manufacturing and modification techniques to obtain bandgap materials that meet customer needs. We are committed to making unremitting efforts to realize the rich application of colloidal crystals in the optical field.

What Can We Do?

• Alfa Chemistry provides different colloidal materials and preparation techniques for photonic band gap research.
• Alfa Chemistry uses surface chemical modification to control the band gap and can provide a comprehensive description of the control phenomenon.
• Alfa Chemistry is able to work with customers to jointly develop multifunctional colloidal photonic crystals or integrate them into the design of various "smart" materials.

References

1. Ding J, et al. Fabrication of Photonic Band Gap Crystals through Colloid Self-Assembly Methods. Progress in Chemistry. 2004, 16(4):492-499.
2. Tao, Xiaoming. Wearable photonics based on integrative polymeric photonic fibres[M]. 2005.
3. Giansante C. Surface Chemistry Control of Colloidal Quantum Dot Band Gap. The Journal of Physical Chemistry C. 2018, 122(31).

Click here to get in touch with us