It has been reported that solid state lighting (SSL) would reduce global electricity consumption by 50%. [1] Specifically, white-light SSL has great potential to replace conventional lighting sources as a much more efficient device. Common approaches are to combine blue, green, and red emitters to achieve a broad spectrum of white light, or by phosphor conversion. But, these procedures lead to significant energy loss such as self absorption associated with light capture by the phosphor or nonradiative carrier losses.[2] Semiconductor nanocrystals (NCs) provide a new technology platform for developing white light phosphors with improved efficiencies, because self absorption and complex doping process can be avoided, and by tailoring the size of NCs emission properties can be tuned. However, a great challenge for these NCs is the difficulties of achieving high carrier mobility and conductivity required for LEDs.

We have developed a new class of inorganic-organic hybrid nanostructured semiconductors that possess broad band gap tunability and high absorption coefficients desirable for opto-electronic applications, such as photovoltaics and solid state lighting. They exhibit both enhanced semiconductor properties and strong quantum confinement effect similar to the smallest NCs. Here we present a unique approach of generating direct white light from a single semiconductor bulk material, 2D-Cd2S2(ba)](ba=butylamine) based double layer structure. Luminescence properties of this hybrid semiconductor can be tuned systematically by changing its composition and doping level.

[1] Solid state Lighting http://lighting.sandia.gov/

[2] A.H. Mueller et al., Nano Lett., 5, 1039 (2005)