White electroluminescence from hybrid organic inorganic LEDs based on thermally evaporated nanocrystals
1 Center for Organic Electronics, CSIR-National Physical Laboratory - Dr. K.S. Krishnan Road, New Delhi-110012, India
2 Instrument Design Development Center, Indian Institute of Technology Delhi - New Delhi-110016, India
Received: 11 April 2012
Accepted: 29 May 2012
Light-emitting diodes (LEDs) with a broad spectral emission have been fabricated using co-evaporated monolayers of cadmium sulfide (CdS) and cadmium telluride (CdTe) nanocrystals in a hybrid organic-inorganic structure. The nanocrystals of CdS and CdTe were grown by vacuum thermal evaporation technique. The incorporation of 50:50 ratio of CdS and CdTe resulted in a broad emission spectrum with CIE coordinates (0.22, 0.33). The fine tuning of the emission spectrum to achieve pure white light (CIE coordinates (0.30, 0.33)) was achieved by incorporating a small quantity of 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyan (DCM) dye in the device structure. The study indicates a promising route towards more stable and efficient light-emitting devices for lighting applications.
PACS: 73.61.Ga – II-VI semiconductors / 81.07.Bc – Nanocrystalline materials / 78.60.Fi – Electroluminescence
© EPLA, 2012