CZTSSe為具有潛力的光電材料，與現在的CdTe或CIGS相比，其組成元素地殼含量豐富，成本低廉且對環境友善。
本研究使用DMSO溶液旋轉塗布法製作CZTSSe薄膜，研究中探討不同烘烤溫度對於前驅物與硒化後之CZTSSe薄膜之影響，利用SEM、EDS分析硒化前後薄膜與成分比例之變化、XRD與Raman確認CZTSSe薄膜之晶體結構，將CZTSSe薄膜製作為元件並透過I-V量測了解其光電特性。
由結果顯示，烘烤溫度較高，薄膜之成分組成較符合合理之比例，其表面緻密度較高，隨後利用不同烘烤條件製作元件，其效率表現也隨烘烤溫度較高而有上升的趨勢。
在烘烤過程中使用混合烤溫的方式能夠進一步使表面緻密度提高，對元件的表現有相當的幫助，使用此方法所製作之元件效率可達4.74%，開路電壓為0.24V，短路電流密度為43.65mA/cm2，填充因子為45.25%。
在溶液中摻雜鉀可有效改善晶粒尺寸與緻密度，與混合烤溫法的相互運用時，其表面會生成細晶層，此細晶層之生成原因仍需進一步探討，最後製作之元件效率並無顯著之助益，其為4.59%，開路電壓為0.28V，短路電流為37.25mA/cm2，填充因子為44.08%。

CZTSSe is a promising material for thin film solar cells, which consists of earth-abundant, low-cost and environmentally friendly material compared to CIGS or CdTe.CZTSe thin films were fabricated using DMSO-based spin coating technique. In this work, we investigate the effects of baking temperature on the precursor and selenized CZTSSe thin film. EDS and SEM were performed before and after selenization to analyze the change of composition and morphology of films. XRD and Raman were used to confirm the crystal structure of CZTSSe thin film. CZTSSe-based device was measured through I-V measurement in order to know the photoelectric property.
The result shows that with higher baking temperature, composition was closer to ideal ratio, denser surface and higher efficiency solar cells were obtained. The surface becomes much denser by using the multi-temperature baking, which is beneficial to the performance of device. The best solar cells showed a conversion efficiency of 4.74%, open-circuit voltage of 0.24V, short-circuit current of 43.65mA/cm2, fill factor of 45.25%.
Through K-doping in the solution could effectively improve the grain size and surface density. While applying this method with multi-temperature baking, a fine grain layer was observed on the surface, the cause of which still needs further investigation. Using this approach, the best solar cells showed a conversion efficiency of 4.59%, open-circuit voltage of 0.28V, short-circuit current of 37.25mA/cm2, fill factor of 44.08%.

[1]W. Shockley and H. J. Queisser, "Detailed Balance Limit of Efficiency of p-n Junction Solar Cells," Journal of Applied Physics, vol. 32, p. 510, 1961.
[2]Q. Guo, H. W. Hillhouse, and R. Agrawal, "Synthesis of Cu2ZnSnS4 Nanocrystal Ink and Its Use for Solar Cells," Journal of the American Chemical Society, vol. 131, pp. 11672-11673, 2009/08/26 2009.
[3]M. T. Winkler, W. Wang, O. Gunawan, H. J. Hovel, T. K. Todorov, and D. B. Mitzi, "Optical designs that improve the efficiency of Cu2ZnSn(S,Se)4solar cells," Energy Environ. Sci., vol. 7, pp. 1029-1036, 2014.
[4]S. Chen, X. G. Gong, A. Walsh, and S.-H. Wei, "Electronic structure and stability of quaternary chalcogenide semiconductors derived from cation cross-substitution of II-VI andI-III-VI2compounds," Physical Review B, vol. 79, 2009.
[5]S. Chen, X. G. Gong, A. Walsh, and S.-H. Wei, "Defect physics of the kesterite thin-film solar cell absorber Cu2ZnSnS4," Applied Physics Letters, vol. 96, p. 021902, 2010.
[6]A. Walsh, S. Chen, S.-H. Wei, and X.-G. Gong, "Kesterite Thin-Film Solar Cells: Advances in Materials Modelling of Cu2ZnSnS4," Advanced Energy Materials, vol. 2, pp. 400-409, 2012.
[7]S. Chen, A. Walsh, X. G. Gong, and S. H. Wei, "Classification of lattice defects in the kesterite Cu2ZnSnS4 and Cu2ZnSnSe4 earth-abundant solar cell absorbers," Adv Mater, vol. 25, pp. 1522-39, Mar 20 2013.
[8]I. D. Olekseyuk, I. V. Dudchak, and L. V. Piskach, "Phase equilibria in the Cu2S–ZnS–SnS2 system," Journal of Alloys and Compounds, vol. 368, pp. 135-143, 2004.
[9]J. J. Scragg, "Studies of Cu2ZnSnS4 films prepared by sulfurisation of electrodeposited precursors," University of Bath, 2010.
[10]Z. Tang, Y. Nukui, K. Kosaka, N. Ashida, H. Uegaki, and T. Minemoto, "Reduction of secondary phases in Cu2SnSe3 absorbers for solar cell application," Journal of Alloys and Compounds, vol. 608, pp. 213-219, 2014.
[11]T. Tanaka, T. Sueishi, K. Saito, Q. Guo, M. Nishio, K. M. Yu, et al., "Existence and removal of Cu2Se second phase in coevaporated Cu2ZnSnSe4 thin films," Journal of Applied Physics, vol. 111, p. 053522, 2012.
[12]L. Vauche, L. Risch, M. Arasimowicz, Y. Sánchez, E. Saucedo, M. Pasquinelli, et al., "Detrimental effect of Sn-rich secondary phases on Cu2ZnSnSe4 based solar cells," Journal of Renewable and Sustainable Energy, vol. 8, p. 033502, 2016.
[13]S. Temgoua, R. Bodeux, N. Naghavi, and S. Delbos, "Effects of SnSe2 secondary phases on the efficiency of Cu2ZnSn(Sx,Se1−x)4 based solar cells," Thin Solid Films, vol. 582, pp. 215-219, 2015.
[14]A. Fairbrother, X. Fontané, V. Izquierdo-Roca, M. Placidi, D. Sylla, M. Espindola-Rodriguez, et al., "Secondary phase formation in Zn-rich Cu2ZnSnSe4-based solar cells annealed in low pressure and temperature conditions," Progress in Photovoltaics: Research and Applications, vol. 22, pp. 479-487, 2014.
[15]W.-C. Hsu, I. Repins, C. Beall, C. DeHart, G. Teeter, B. To, et al., "The effect of Zn excess on kesterite solar cells," Solar Energy Materials and Solar Cells, vol. 113, pp. 160-164, 2013.
[16]J. r. Timo Wätjen, J. Engman, M. Edoff, and C. Platzer-Björkman, "Direct evidence of current blocking by ZnSe in Cu2ZnSnSe4 solar cells," Applied Physics Letters, vol. 100, p. 173510, 2012.
[17]H. Katagiri, K. Jimbo, K. Moriya, and K. Tsuchida, "Solar cell without environmental pollution by using CZTS thin film," in Photovoltaic Energy Conversion, 2003. Proceedings of 3rd World Conference on, 2003, pp. 2874-2879.
[18]Y. Yang, X. Kang, L. Huang, S. Wei, and D. Pan, "Facile and Low-Cost Sodium-Doping Method for High-Efficiency Cu2ZnSnSe4 Thin Film Solar Cells," The Journal of Physical Chemistry C, vol. 119, pp. 22797-22802, 2015.
[19]Y. Yang, G. Wang, W. Zhao, Q. Tian, L. Huang, and D. Pan, "Solution-processed highly efficient Cu2ZnSnSe4 thin film solar cells by dissolution of elemental Cu, Zn, Sn, and Se powders," ACS Appl Mater Interfaces, vol. 7, pp. 460-4, Jan 14 2015.
[20]Z. Tong, C. Yan, Z. Su, F. Zeng, J. Yang, Y. Li, et al., "Effects of potassium doping on solution processed kesterite Cu2ZnSnS4 thin film solar cells," Applied Physics Letters, vol. 105, p. 223903, 2014.
[21]Y.-T. Hsieh, Q. Han, C. Jiang, T.-B. Song, H. Chen, L. Meng, et al., "Efficiency Enhancement of Cu2ZnSn(S,Se)4 Solar Cells via Alkali Metals Doping," Advanced Energy Materials, vol. 6, p. 1502386, 2016.
[22]C. M. Sutter-Fella, J. A. Stückelberger, H. Hagendorfer, F. La Mattina, L. Kranz, S. Nishiwaki, et al., "Sodium Assisted Sintering of Chalcogenides and Its Application to Solution Processed Cu2ZnSn(S,Se)4 Thin Film Solar Cells," Chemistry of Materials, vol. 26, pp. 1420-1425, 2014.
[23]K. F. Tai, D. Fu, S. Y. Chiam, C. H. Huan, S. K. Batabyal, and L. H. Wong, "Antimony Doping in Solution-processed Cu2ZnSn(S,Se)4 Solar Cells," ChemSusChem, vol. 8, pp. 3504-11, Oct 26 2015.
[24]H. Xin, S. M. Vorpahl, A. D. Collord, I. L. Braly, A. R. Uhl, B. W. Krueger, et al., "Lithium-doping inverts the nanoscale electric field at the grain boundaries in Cu2ZnSn(S,Se)4 and increases photovoltaic efficiency," Phys Chem Chem Phys, vol. 17, pp. 23859-66, Oct 7 2015.
[25]K. Ito and T. Nakazawa, "Electrical and optical properties of stannite-type quaternary semiconductor thin films," Japanese Journal of Applied Physics, vol. 27, p. 2094, 1988.
[26]H. Katagiri, N. Sasaguchi, S. Hando, S. Hoshino, J. Ohashi, and T. Yokota, "Preparation and evaluation of Cu2ZnSnS4 thin films by sulfurization of E-B evaporated precursors," Solar Energy Materials and Solar Cells, vol. 49, pp. 407-414, 1997.
[27]F. TM, W. N, W. T, D. H, and S. HW, "Heterojunctions based on Cu2ZnSnS4 and Cu2ZnSnSe4 thin films," Proceedings of the 14th European Photovotlaic Specialists Conference, Barcelona, pp. 1242-1245, 1997.
[28]J.-S. Seol, S.-Y. Lee, J.-C. Lee, H.-D. Nam, and K.-H. Kim, "Electrical and optical properties of Cu2ZnSnS4 thin films prepared by rf magnetron sputtering process," Solar Energy Materials and Solar Cells, vol. 75, pp. 155-162, 2003.
[29]H. Katagiri, "Survey of development of CZTS-based thin film solar cells," in 2012 IEEE 3rd International Conference on Photonics, 2012, pp. 345-349.
[30]G. Zoppi, I. Forbes, R. W. Miles, P. J. Dale, J. J. Scragg, and L. M. Peter, "Cu2ZnSnSe4 thin film solar cells produced by selenisation of magnetron sputtered precursors," Progress in Photovoltaics: Research and Applications, vol. 17, pp. 315-319, 2009.
[31]K. Tanaka, N. Moritake, and H. Uchiki, "Preparation of Cu2ZnSnS4 thin films by sulfurizing sol–gel deposited precursors," Solar Energy Materials and Solar Cells, vol. 91, pp. 1199-1201, 2007.
[32]K. Tanaka, M. Oonuki, N. Moritake, and H. Uchiki, "Cu2ZnSnS4 thin film solar cells prepared by non-vacuum processing," Solar Energy Materials and Solar Cells, vol. 93, pp. 583-587, 2009.
[33]K. Tanaka, Y. Fukui, N. Moritake, and H. Uchiki, "Chemical composition dependence of morphological and optical properties of Cu2ZnSnS4 thin films deposited by sol–gel sulfurization and Cu2ZnSnS4 thin film solar cell efficiency," Solar Energy Materials and Solar Cells, vol. 95, pp. 838-842, 2011.
[34]K. Moriya, K. Tanaka, and H. Uchiki, "Fabrication of Cu2ZnSnS4Thin-Film Solar Cell Prepared by Pulsed Laser Deposition," Japanese Journal of Applied Physics, vol. 46, pp. 5780-5781, 2007.
[35]J. J. Scragg, P. J. Dale, L. M. Peter, G. Zoppi, and I. Forbes, "New routes to sustainable photovoltaics: evaluation of Cu2ZnSnS4 as an alternative absorber material," physica status solidi (b), vol. 245, pp. 1772-1778, 2008.
[36]T. Kato, H. Hiroi, N. Sakai, and H. Sugimoto, "Buffer/absorber interface study on Cu2ZnSnS4 and Cu2ZnSnSe4 based solar cells: band alignment and its impact on the solar cell performance," in Proc. 28th European Photovoltaic Solar Energy Conf. Exhib, 2013, pp. 2125-2127.
[37]Y. S. Lee, T. Gershon, O. Gunawan, T. K. Todorov, T. Gokmen, Y. Virgus, et al., "Cu2ZnSnSe4Thin-Film Solar Cells by Thermal Co-evaporation with 11.6% Efficiency and Improved Minority Carrier Diffusion Length," Advanced Energy Materials, vol. 5, p. 1401372, 2015.
[38]W. Wang, M. T. Winkler, O. Gunawan, T. Gokmen, T. K. Todorov, Y. Zhu, et al., "Device Characteristics of CZTSSe Thin-Film Solar Cells with 12.6% Efficiency," Advanced Energy Materials, vol. 4, p. 1301465, 2014.
[39]S. Oueslati, G. Brammertz, M. Buffière, H. ElAnzeery, O. Touayar, C. Köble, et al., "Physical and electrical characterization of high-performance Cu2ZnSnSe4 based thin film solar cells," Thin Solid Films, vol. 582, pp. 224-228, 2015.
[40]S. Tajima, H. Katagiri, K. Jimbo, N. Sugimoto, and T. Fukano, "Temperature Dependence of Cu2ZnSnS4 Photovoltaic Cell Properties," Applied Physics Express, vol. 5, p. 082302, 2012.
[41]K. Wang, O. Gunawan, T. Todorov, B. Shin, S. J. Chey, N. A. Bojarczuk, et al., "Thermally evaporated Cu2ZnSnS4 solar cells," Applied Physics Letters, vol. 97, p. 143508, 2010.
[42]J. Tao, K. Zhang, C. Zhang, L. Chen, H. Cao, J. Liu, et al., "A sputtered CdS buffer layer for co-electrodeposited Cu2ZnSnS4 solar cells with 6.6% efficiency," Chem Commun (Camb), vol. 51, pp. 10337-40, Jun 28 2015