White-light emitting single compounds were synthesized by grafting blue-fluorescent molecules onto yellow emitting CdSe/ZnS quantum dots and white light emitting diodes were demonstrated. Facile adjustment of color temperature was also demonstrated by controlling the size of quantum dots and the amount of grafted organic blue-emitting molecules.

The red, green, and blue emitters with relatively equal stability, efficiency, and color purity are needed to achieve full-color displays for organic light emitting diode (OLED). 1,2Compared with red and green emitters, 3,4 further improvement of blue-emitting OLED materials is still required. 5Generally, it is very difficult to develop new blue-emitting materials with excellent electroluminescence property because of their intrinsic wide band gap. Several blue-emitting OLED materials with high brightness and good stability such as distyrylarylene 6 and anthracene derivatives 7-17 have been developed. In spite of their excellent electronic and optical properties, these organic π-conjugated materials have some problems about device failure and thermal stability. Recently, new silicon-cored anthracene derivatives were reported in the literature to overcome such problems and to improve thermal properties.18 In this regard, we designed a new blue-emitting anthracene derivative having siliconsubstituent such as 2-triphenylsilyl-9,10-di-1-naphthalenylanthracene (1) to combine two concepts from anthracene derivative with excellent electronic/optical properties and silicon-cored system with improved thermal stability. The introduction of the bulky triphenylsilyl group in 2 position of anthracene and naphthalenyl groups in 9, 10 positions of anthracene may prevent the aggregation of planar anthracenes as well as increase the chemical stability, the thermal stability, and solubility, which results in a bright blue EL emission.Scheme 1 illustrates the synthetic route for compound 1 via reaction of 2-bromo-9,10-di-1-naphthalenylanthracene, which is prepared according to a published procedure, 19 with n-BuLi followed by chlorotriphenylsilane. Compound 1 was obtained as air-stable colorless powder in the yield of 39%. The formation of 1 has been confirmed by 1 H and 13 C{ 1 H} NMR spectroscopy and high-resolution mass spectrometry. The thermal property of 1 was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) under a nitrogen atmosphere. TGA curve showed that 1 exhibits excellent thermal stability with its 5% weight loss temperature (ΔT 5% ) at 351 o C, which is stable enough to endure the high temperature for the vacuum vapor deposition. Also, the morphological stability of 1 was monitored by DSC, which was performed from 0 to 450 o C at a heating rate of 10 o C/min and a glass transition temperature (T g ) and melting temperature (T m ) occurred at 254 o C and 332 o C, respectively. The results of the second scan were recorded to eliminate differences from the sample history. Despite relatively low molecular weight of 1, its excellent thermal stability might be originated from both the steric protection of triphenylsilyl group and non-planarity of its molecular structure.As shown in Figure 1, the optical properties of 1 were investigated by means of UV-Vis absorption and photoluminescence (PL) spectroscopy. 1 in dilute toluene solution exhibits the characteristic π-π* transition p...