Recent Advances in Binary Colloidal Crystals for Photonics and Porous Material Fabrication

In the past few years, binary colloidal crystals (BCCs) composed of both large and small particles have attracted considerable attention from the scientific community as an exciting alternative to single colloidal crystals (SCCs). In particular, more complex structures with diverse nanotopographies and desirable optical properties of BCCs can be obtained by various colloidal assembly methods, as compared to SCCs. Furthermore, high accuracy in crystal growth with controllable stoichiometries allows for a great deal of promising applications in the fields of both interfacial and material sciences. The visible-light diffraction property of BCCs is more superior than that of SCCs, which makes them have more promising applications in the fabrication of photonic crystals with full band gaps. On the other hand, their spherical shapes and ease of removal property make them ideal templates for ordered porous material fabrication. Hence, this perspective outlined recent advances in assembly approaches of BCCs, with an emphasis on their promising applications for advanced photonics and multifunctional porous material fabrication. Eventually, some challenging yet important issues and some future perspectives are further discussed.