Enhanced DispersionofCdSe/MEH-CN-PPV Hybrid Nanocomposites by in situ Polymerization using AEM as Photopolymerizable Precursor

(Supplementary materials)

Yushin Park·Jaehong Park· Michael J. Therien·Adrienne D. Stiff-Roberts

Yushin Park·Adrienne D. Stiff-Roberts

Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA

Jaehong Park· Michael J. Therien

Department of Chemistry, Duke University, Durham, NC 27708, USA

Jaehong Park

Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA

Phone: 919-660-5560

Fax: 919-660-5293

E-mail:

Two main peaks at approximately 3.5 ppm and 4.5 ppm due to the ethyl group proximal to the amine did not shift and remained the same even after two-hour polymerization. However, two peaks at approximately 5.6 ppm and 6.3 ppm due to the vinyl moiety, and a peak at approximately 2 ppmdue to the methyl group next to the vinyl of AEM are disappeared and replaced by peaks around 1~2 ppm by alky moiety.

Fig.S1 1HNMR (400 MHz) spectra of AEM, PAEM, CdSe-TOPO CQDs, MEH-CN-PPV in Chloroform-d(99.8%, with 0.03% TMS).

The IR absorption spectra for the CdSe CQDs/MEH-CN-PPV/AEM (Sample 2), CdSe CQDs/MEH-CN-PPV/PAEM (Sample 3) and photopolymerized CdSe CQDs/MEH-CN-PPV/AEM (Sample 4) shown in Fig.S2 also exhibited carbonyl peaks as in the AEM and PAEM IR reference spectra, thereby indicating that AEM and PAEM remain in the samples without decomposition. In these samples, MEH-CN-PPV has C=C moieties in the PPV backbone that do not show a significant difference at 1650 cm-1 as in the AEM- and PAEM-only samples. A peak appearing at 2220 cm-1, which corresponds to the nitrile group on MEH-CN-PPV, also remained the same in the four samples. These data indicate that the MEH-CN-PPV was not affected by the added chemicals or photopolymerization.

Fig.S2 FTIR spectra ofCdSe/MEH-CN-PPV nanocomposite and nanocomposites with AEM, with PAEM, and CdSe CQDs, MEH-CN-PPV,AEM and PI blends (CdSe CQDs:MEH-CN-PPV:AEM:PI = 5:1:1:0.05) after photopolymerization on Si wafer(long wavelength UV of 365nm with a power density of 470 µW/cm2).

UV irradiation does not impact the optical properties of CdSe CQD/ MEH-CN-PPV nanocomposites that do not contain AEM, PAEM or the PI. The absorption spectra of the CdSe CQD/MEH-CN-PPV nanocomposite before and after exposure to UV light are shown in Fig. S3. For both spectra, the peaks attributed to the CdSe CQDs (570nm) and MEH-CN-PPV (470 nm) were not changed after the UV irradiation of the nanocomposite. These spectra also demonstrate that the CdSe CQDs and MEH-CN-PPV were not significantly degraded after UV irradiation.

Fig.S3. Absorption spectra of CdSe CQDs/MEH-CN-PPV nanocomposites before UV irradiation and after UV irradiation (365 nm, power density of 470 µW/cm2) for 2 hrs.

The absorption and emission spectra of the CdSe CQDs and MEH-CN-PPV, shown in Figs. S4 a. and b., respectively,were obtained using a 442 nm excitation.The CdSe CQDs and MEH-CN-PPV absorb light maximally at 570 nm and 470 nm, respectively. They also emit light maximally at 580 nm and 550 nm, respectively, when they are excited at 442 nm.

Fig.S4. Absorbance and emission spectra at 442 nm excitation ofa) CdSe quantum dots, and b) MEH-CN-PPV.

References

(1)Kang B-H, Seo J–S, Jeong S, Lee J, Han C–S, Kim D–E, Kim K–J, Yeom S–H, Kwon D–H, Kim H–R, Kang S–W (2010)Highly efficient hybrid light-emitting device using complex of CdSe/ZnS quantum dots embedded in co-polymers as an active layer. Opt Express 18:18303-18311