White-light emitting materials can be made using different approaches. One is to combine components that emit blue, red, and green light.

Xiang-Jun Zheng and colleagues, Beijing Normal University, China, used the blue-emitting ligand imidazole-3,4-dicarboxylate (imdc) to form lanthanide–cadmium metal–organic frameworks. Doping red-emitting europium(III) and green-emitting terbium(III) ions into the framework lanthanide sites otherwise occupied by gadolinium or praseodymium yields a material that emits white light upon excitation. The color of the emitted light can be tuned from yellow to white by changing the excitation wavelength and by controlling the relative ratio of Eu, Tb, and Gd or Pr.

The authors comment that white-light-emitting materials are important for solid-state lighting applications and full-color displays.

• Luminescence Tuning and White-Light Emission of Co-doped Ln–Cd–Organic Frameworks,
  Ayjamal Ablet, Shu-Mu Li, Wei Cao, Xiang-Jun Zheng, Wing-Tak Wong, Lin-Pei Jin,
  Chem. Asian J. 2012.
  DOI: 10.1002/asia.201200813