HYBRID INORGANIC/ORGANIC NANOCOMPOSITES CONSISTING OF CUINS 2 -ZNS - PDF document

18 TH INTERNATIONAL CONFERENCE ON COMPOSITE MATERIALS HYBRID INORGANIC/ORGANIC NANOCOMPOSITES CONSISTING OF CUINS 2 -ZNS CORE-SHELL QUANTUM DOTS EMBEDDED IN A POLY(METHYLMETHACRYLATE) MATRIX Gyu Wan Han 1 , Jung Min Son 2 , Dong Yeol Yun 3 , Tae Whan Kim 1,2,3,* , Sung Woo Kim 4 , and Sang Wook Kim 4 1 Department of Information Display Engineering, Hanyang University, Seoul, Korea 2 Department of Electronics and Computer Engineering, Hanyang University, Seoul, Korea 3 Division of Nanoscale Semiconductor Engineering, Hanyang University, Seoul, Korea 4 Department of Molecular Science & Technology, Ajou University, Suwon, Korea * Corresponding author (twk@hanyang.ac.kr) Keywords : CuInS 2 -ZnS core-shell quantum dot, PMMA, nanocomposites Abstract due to their being environment-friendly materials in CuInS 2 (CIS) - ZnS core-shell quantum dots (QDs) comparison with core-shell QDs containing Cd and were formed by a using sol-gel method, and Pb atoms and to their promising applications in next- nanocomposites consisting of CIS-ZnS core-shell generation electronic devices. Even though some QDs embedded in the poly(methymethacrylate) studies concerning the formation and the materials (PMMA) matrix were formed by a using spin- characteristics of binary core-binary shell coating method. A absorption peak at 550 nm for the QDs/polymer nanocomposites have been conducted absorbance spectra corresponded to the optical [13-16], very few works on the formation and the excitation edge of the CIS-ZnS core-shell QDs. A applications of the ternary core-binary shell peak at 700 nm for the PL spectrum was related to QDs/polymer nanocomposites have been performed. the recombination luminescence of the CIS-ZnS This paper reports data for formation processes and core-shell QDs. Capacitance-voltage curves for feasibility results of the hybrid nanocomposites Al/CIS-ZnS QDs embedded in PMMA/p-Si device consisting of CIS-ZnS core-shell QDs embedded in showed a hysteresis behavior with a flat band the poly(methymethacrylate) (PMMA) matrix for voltage shift. possible applications in nonvolatile memory devices. Absorbance and photoluminescence (PL) 1. Introduction measurements were carried out to investigate the Hybrid inorganic/organic nanocomposites have been optical properties of CIS-ZnS core-shell QDs. currently receiving considerable attention because of Capacitance-voltage (C-V) measurements were their promising applications in flexible electronic performed to investigate the possibility for devices operating at lower powers [1-7]. The applications of nanocomposites consisting of core- prospect of potential applications in electronic shell CIS-ZnS QDs embedded in a PMMA matrix in devices has led to substantial research and nonvolatile memory devices. development efforts to form various nanocomposites containing inorganic nanocomposites, acting as 2. Experimental Details charge storage regions [8-12]. Nanocomposites Inorganic/organic nanocomposites consisting of the containing core-shell quantum dots (QDs) have colloidal CIS-ZnS QDs and the PMMA polymer emerged as excellent candidates for promising layer used in this study were prepared on p-Si (100) applications in electronic devices. Among the substrates. The formation process of the CIS-ZnS several types of QDs, CuInS 2 (CIS)-ZnS ternary QDs solution was started by using a CIS core core-shell QDs have been particularly interesting solution [17]. The solution consisting of 8 ml of

octadecene (ODE), 0.1 mMol of indium acetate, and The schematic diagrams of (a) the CIS-ZnS core-cell 0.3 mMol of miristic acid were mixed in a 25-ml nanoparticles and (b) nanocomposites of CIS-ZnS three-neck flask. Then, the mixed solution was core-shell QDs embedded in PMMA matrix and the degassed at 110 o C for 2 h and was injected with a chemical structure of the PMMA layer are shown in Cu-thiol stock solution at 250 o C. The schematic Fig. 3 [18]. diagrams of the formation processes of the CIS-ZnS core-shell QDs are shown in Fig. 1. Subsequently, Blended the solution was heated at 200-210 o C for 2 h. 0.3 Solution Nanocomposite mMol of copper iodide, was mixed with 3 ml of Sample dodecanethiol, for the synthesis of the Cu-thiol stock solution. Then, the mixed solution was slightly heated on a hot-plate while being stirred. After the synthesis of the CIS core solution was finished, the synthesized solution was in-situ cooled to form the p-Si p-Si Spin coating ZnS shell at room temperature. Zn acetate, 0.5 mMol, was added to the CIS core solution, and the solution Fig. 2. A schematic of the formation processes of was heated to 230 o C. Then, the solution was aged nanocomposites consisting of the CIS-ZnS core- for 1.5 h at 230 o C. To fabricate the CIS-ZnS core- shell QDs. shell QDs blended with a PMMA layer, The 150 mg PMMA polymer insulator was dissolved in (a) (b) chlorobenzene (4.85 g) solvent for a 3 wt% PMMA solution. Then, CIS-ZnS core-shell QDs (5.5 mg) n The CI CIS (cor ore) chemical blended into PMMA solution. Subsequently, structure of PMMA ultrasonication was performed for over 1 h to obtain uniform solutions. The blended solutions treated by ` ` ` ` ` using ultrasonic were spin-coated on p-Si substrates. ` ` ` ` ` ` ` ` The schematic diagrams of the formation processes PMMA of the nanocomposites of the CIS-ZnS core-shell QDs embedded in a PMMA are shown in Fig. 2. CI CIS-ZnS nS cor ore-shel hell / ZnS nS (shel hell) PMMA nanoc nanocom ompos posites es Indi ndium um ac acet etat ate + Miristic ac acid Fig. 3. (a) Schematic diagrams of the CIS-ZnS QDs Octadec adecene ene and (b) nanocomposites consisting of CIS-ZnS QDs CI CIS (cor ore) Anneal nnealing ng embedded in a PMMA matrix and the chemical structure of PMMA. Copper Copper iodi odide de + Dodec Dodecanet anethi hiol ol The optical absorption measurements were performed by using an ultraviolet-visible spectrometer (Scinco PDA S-3100). The PL Anneal nnealing ng measurements were carried out using a 75 cm monochromator equipped with a GaAs Zn n ac acet etat ate ZnS nS (shel hell) phtomultiplier tube (Ocean Optics usb-400). The + Agi ging ng excitation source was the 355 nm line of a CWUV laser. C-V measurements were performed by using an HP 4284 precision LCR meter at room temperature. ` ` Ds ) (CI CIS-ZnS nS cor ore-shel hell QDs ` ` ` 3 Results and Discussion Fig. 1. A schematic of the formation processes of the Figure 4 shows optical absorbance and PL spectra of CIS-ZnS core-shell QDs. CIS-ZnS core-cell QDs. The broad absorption peak