Experimental study of the effect of addition of gold nanoparticles on CdSe quantum dots sensitized solar cells Cite as: AIP Conference Proceedings 1788, 030132 (2017); https://doi.org/10.1063/1.4968385 Published Online: 03 January 2017 Wahyu Indayani, Ichsanul Huda, Herliansyah, Fasya Khuzaimah, Musyaro’ah, Bodi Gunawan, and Endarko ARTICLES YOU MAY BE INTERESTED IN Fabrication and characterization dye sensitized solar cell (DSSC) based on TiO2/SnO2 composite AIP Conference Proceedings 1788, 030062 (2017); https://doi.org/10.1063/1.4968315 Performance enhancement of dye-sensitized solar cells (DSSCs) using a natural sensitizer AIP Conference Proceedings 1788, 030123 (2017); https://doi.org/10.1063/1.4968376 The influence of various concentrations of N-doped TiO2 as photoanode to increase the efficiency of dye-sensitized solar cell AIP Conference Proceedings 1788, 030128 (2017); https://doi.org/10.1063/1.4968381 AIP Conference Proceedings 1788, 030132 (2017); https://doi.org/10.1063/1.4968385 © 2016 Author(s). 1788, 030132 Experimental Study of The Effect of Addition of Gold Nanoparticles on CdSe Quantum Dots Sensitized Solar Cells Wahyu Indayani1, b), Ichsanul Huda1, c), Herliansyah1, d), Fasya Khuzaimah1, e), Musyaro’ah1, f), Bodi Gunawan1, g), Endarko1, a) 1 Physics Department, Institut Teknologi Sepuluh Nopember, Sukolilo Surabaya 60111, East Java, Indonesia a) Corresponding author: endarko@physics.its.ac.id b) wahyu.indayani@gmail.com c) ichsanulhuda13@gmail.com d) herlistand14@gmail.com e) khzfasya@gmail.com f) mail4bodi@gmail.com g) musya.saroh@gmail.com Abstract. The effect of the gold nanoparticles on the quantum dots sensitized solar cells has been investigated. Gold nanoparticles were added in quantum dot CdSe before used as a sensitizer. The result showed that addition of colloidal gold nanoparticles could be enhanced the absorbance of quantum dot CdSe sensitizer. In this research, the QDSCs were arranged in the sandwich structure consecutively TiO2 as photoelectrode, gold nanoparticle, and quantum dot CdSe as a sensitizer, KI as electrolyte and black carbon as counter-electrode. The use of gold nanoparticles and quantum dot improved the average efficiency of the QDSC by about 104%. INTRODUCTION Recently, nanotechnology has been receiving increasing attention in science and engineering. The most interesting studied is the use of nanomaterials for enhancing solar cells performance [1]. It is motivated by continuously rising global energy demands and the decimation of fossil fuels. More than 80% of energy consumption in the circulation is derived from fossil fuels, whereas fossil fuel would be exhausted soon [2]. Therefore, the search for renewable energy source has become vital. Among the renewable energy source, solar cells, which converts solar light into electric energy have a great interest. The most famous solar cells are silicon based, but it has high cost and difficult production. Because of that issues should be resolved, on 1991, O’Regan and Gratzel were reported dye-sensitized solar cells. A dye-sensitized solar cell is the third generation of solar cells and a class of photoelectrochemical cells. DSSCs have been receiving increasing attention as a future generation of solar cells due to their low-cost production and simple fabrication process [3, 4]., There are many efforts which have been made on the development of each element of DSSCs to improve the performance of DSSC. Many studies have focused on the photoelectrode, especially sensitizer because it takes a fundamental role in the enhancement of DSSC's efficiency [4]. Recent research in DSSC is the emergence of the quantum dots (QDs) which using as sensitizer component. It shows promising developments for the next solar cells [5]. Quantum dots are nanocrystal semiconductors, composed of periodic groups of II-VI, III-V, or IV-VI materials [6]. It has been used as an alternative to ruthenium dyes in DSSC to increase performance and reduce cost due to their optical and electrical properties. QDs have tunable band gap depending on the QD's size and large extinction coefficient in the visible region [1, 5]. The emergence of the quantum dots drove the DSSC terminology becomes quantum dots sensitized solar cells (QDSCs). International Conference on Engineering, Science and Nanotechnology 2016 (ICESNANO 2016) AIP Conf. Proc. 1788, 030132-1–030132-5; doi: 10.1063/1.4968385 Published by AIP Publishing. 978-0-7354-1452-5/$30.00 030132-1 Quantum dots sensitized solar cells is almost identical to dye-sensitized solar cells with the exception that now the QDs are the sensitizer replacing the organic dye. Quantum dots sensitized solar cells (QDSCs) are considered as a promising candidate of the next generation solar cells. Therefore, the development of nanotechnology, especially the application of nanomaterials on solar cells, receive more and more interest [7]. Gold nanoparticles are one of metal nanomaterial that takes a deep studied on this subject. Several groups have studied the interaction between quantum dots and gold nanoparticle and their application on solar cells. In 2007, Hsieh et al. [8] observed Au/CdSe nanocomposites and reported the enhancement of the emission from CdSE QDs and the gold nanoparticle is a result of the interplay between the increased QD's excitation. In 2010, Zhu et al. [7] fabricated quantum dots sensitized solar cells with gold nanoparticles as QDSC's interfacial layer and reported that the power conversion efficiency increased about 88% higher than QDSCs without the gold nanoparticles interfacial layer. In 2016, Zarazua et al. [1] showed that the electrophoretic deposition of gold nanoparticles could improve the photo-conversion efficiency of QDSCs. In this article, the characteristic of QDSCs using the addition of gold nanoparticle as the sensitizer is investigated. The absorption spectra using ultraviolet-visible spectroscopy and photocurrent-voltage (I-V) characteristic of the cells are also studied. EXPERIMENTAL Characterization The understanding of Quantum dots sensitized solar cells would be known by doing some characterization. There were three characterizations had been done. Phase and crystal size of the semiconducting oxide (TiO2) were observed and analyzed by X-Ray Diffractometer (XRD). The absorption spectra of the colloidal gold nanoparticle, CdSe quantum dots, and their mixing were measured in the range of 300 1000 nm using an Ultraviolet-Visible (UV-Vis) Spectrophotometer. Photocurrent-voltage was examined using the solar simulator with a light source of 100 mW Xenon lamp. Preparation of Quantum-dots Sensitized Solar Cells Synthesize of TiO2 Nanoparticles Co-precipitation method was used to synthesize TiO2 nanoparticles with TiCl3 as the precursor. 20 mL of TiCl3 was mixed with 100mL aquades and was then stirred. The solution was added with NH4OH until the solution at pH 9. After that, the solution washed and evaporated by the furnace with three hours holding time. Preparation of Sensitizer Three kinds of sensitized would be used in this study. The first sensitizer was pure CdSe Quantum Dots, second and third sensitizer were prepared from a mixture of gold nanoparticle and CdSe quantum dots in colloidal solutions with comparison 20:1 and 40:1 (QDs: Au NPs), respectively. After this addition, the solutions would be used to soak the photoelectrode for three hours. The QDSCs Counter Electrode The counter electrode in QDSCs contains a catalyst for reducing the redox couple [4]. The catalyst used in this study was black carbon. 3.5 g black carbon powder was dissolved in15 mL ethanol and was then mixed using magnetic stirrer. Furthermore, carbon solution was deposited on the indium-coated tin oxide (ITO) glass and was then sintered by hotplate. The Electrolyte Gel The electrolyte in QDSCs function as the medium transport electrons from the counter electrode to the quantum dots. In this study, the iodine-triiodide (I3-/I-) was used as the redox couple. The gel electrolyte prepared from a 030132-2 mixture of a liquid electrolyte (KI, acetonitrile, and iodine), PEG and chloroform. The mixed solutions stirred for one hour using magnetic stirrer at 80°C to produce gel electrolyte. Fabrication of QDSCs The QDSCs were fabricated in a sandwich structure with TiO2 as photoelectrode, gold nanoparticle, and quantum dot CdSe as a sensitizer, KI as electrolyte and black carbon as counter-electrode. RESULTS AND DISCUSSION The Characteristic of TiO2 Figure 1 shows the X-Ray diffraction patterns of TiO2 nanoparticles synthesized by co-precipitation method. The phase and the crystal size of TiO2 were determined with Match! and MAUD, respectively. The result showed that the pattern diffraction of XRD measurement was corresponding to the peak of TiO 2 anatase. The crystal size of TiO2 nanoparticles is 11,1 nm. (a) FIGURE 1. XRD pattern of the synthesized anatase nanoparticles Optical Absorption Generally, gold nanoparticles display a single absorption peak in visible range between 500  550 nm. Figure 2a shows the absorption spectra of gold nanoparticles. The absorption spectrum for gold nanoparticle had a peak at 530 nm. The absorption spectra of the quantum dot before and after the addition of gold nanoparticles as shown in Fig. 2b. Upon addition of gold nanoparticle, the absorption of quantum dot improved in the range of 400  650 nm. 030132-3 (a) (b) FIGURE 2. Absorbance spectra (a) Gold nanoparticles, (b) CdSe Quantum dots in water and CdSe Quantum Dots upon adding Gold nanoparticles QDSCs Performance The efficiency characteristic of solar cells is common parameters to find out how far solar cells work. The DSSC prototypes have been examined on the solar simulator, to measure values of the open circuit voltage (Voc), the shortcircuit photocurrent density (Jsc), the photovoltage (Vmax), and the photocurrent density (Jmax). The calculated Voc, Jsc, Vmax, and Jmax determined from Fig. 3. FIGURE 3. J-V curve of QDSCs The results indicate that the enhancement of quantum dots absorption significantly improved the efficiency of quantum dot sensitized solar cells as summarized in Table 1. Table 1 shows that addition of gold nanoparticle on the quantum dot as sensitizer could enhance the effectiveness of solar cells. 030132-4 Variation CdSe QDs CdSe QDs + GNP (40:1) CdSe QDs + GNP (20:1) TABLE 1. J-V characteristics of quantum dots sensitized solar cells Voc (V) Jsc (mA/cm2) Vmax (V) Jmax (mA/cm2) 0.58 0.64 0.72 0.088 0.107 0.111 0.36 0.44 0.58 0.058 0.074 0.091 FF 41 48 66 (%) 0.021 0.033 0.053 Third QDSCs variation shows the highest short circuit current (Jsc) with comparison CdSe QDs + GNP (20:1). It indicates that the semiconductor TiO2 absorbs a lot of sensitizers, so more photons are absorbed by the sensitizer, and QDSCs performance was enhanced. Short circuit current value is related to photocurrent of the device [3]. Third QDSCs variation shows the highest open circuit voltage (Voc) with comparison CdSe QDs + GNP (20:1). CONCLUSION In summary, we have examined the interaction between water-soluble quantum dot CdSe and gold nanoparticles using UV-Vis absorption spectroscopy. It was found that the absorption of water-soluble quantum dot CdSe could be improved by the addition of gold nanoparticles. By examining the photocurrent-voltage using the solar simulator, we had known that the sensitizer absorbance enhancement significantly the efficiency of quantum dot sensitized solar cells. ACKNOWLEDGMENTS This research was funded by the Ministry of Research, Technology, and Higher Education of the Republic of Indonesia and was supported by Department of Physics, Institut Teknologi Sepuluh Nopember. REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. 9. I. Zarazúa, D. Esparza, T. López-Luke, A. Ceja-Fdez, J. Reyes-Gomez, I. Mora-Seró and E. de la Rosa, Electrochim. Acta 188, 710–717 (2016) J. Yoon, Y. Sun and J.A. Rogers, “Chapter 6 - Flexible Solar Cells Made of Nanowires/Microwires,” in Semiconductor Nanomaterials for Flexible Technologies, edited by Yugang Sun and John A Rogers (William Andrew Publishing, Oxford, 2010), pp. 159–196. J.-K. Lee and M. Yang, Mater. Sci. Eng. B. 176(15), 1142–1160 (2011) M. Ye, X. Wen, M. Wang, J. Iocozzia, N. Zhang, C. Lin and Z. Lin, Mater. 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