鈣鈦礦為新興太陽能電池材料，並且近年已有許多研究報導其光電性質[1,2]，但少有提及表面形貌。在先前研究中我們發現鈣鈦礦MAPbBr3無法在鐵鈀合金表面形成均勻且連續的薄膜，會呈現奈米柱狀結構並且有裸露的合金金屬層[9]。在本實驗中，我們發現以石墨烯層插層於鈣鈦礦與鐵磁層之間可使鈣鈦礦形成均勻連續薄膜。由原子力顯微鏡 (AFM) 剖面圖可觀察到：在鐵磁層表面粗糙度小於1 nm，在轉移石墨烯後約有 2 nm，在旋塗鈣鈦礦之後約有6 nm。在AFM形貌圖以及剖面圖可以看出鈣鈦礦於石墨烯上形成連續薄膜。此技術應用於元件製成可防止鈣鈦礦與金屬層的層間短路，使元件正常運作。
二硫化鉬具有良好的載子遷移率，可作半導體材料，但仍有光吸收率相對不高的缺點[3]。鈣鈦礦/二硫化鉬異質結構具有較高光吸收率。但雖有許多關於鈣鈦礦/二硫化鉬結構光電性質的文章[4,5]，但對於鈣鈦礦在二硫化鉬上表面形貌的研究仍然缺乏。將鈣鈦礦旋塗於二硫化鉬上之後，在AFM形貌圖仍可分辨二硫化鉬的形狀，並且可見在二硫化鉬上的鈣鈦礦較基板上的緻密。在SEM圖的分析中，在二硫化鉬上的鈣鈦礦粒徑約在20 nm，在基板上約在30 nm。旋塗鈣鈦礦會造成二硫化鉬光致發光 (PL) 峰值的猝滅，並且造成峰值紅移。依文獻報導猝滅是因為鈣鈦礦到二硫化鉬的電荷轉移，紅移是因為二硫化鉬上量子點的n型摻雜效應[4]。形狀會影響二硫化鉬PL峰值。在旋塗鈣鈦礦後，缺角三角形二硫化鉬的PL峰值較三角形位移多，在3 ~12 nm區間，三角形的位移則在3 nm以內。在旋塗鈣鈦礦之後量測鈣鈦礦PL峰值位置，缺角三角形上的鈣鈦礦PL峰值比起三角形二硫化鉬藍移3 ~ 5 nm。文獻[52]中提及鈣鈦礦顆粒大小會影響PL峰值高低，我們推測可能由於三角形與缺角三角形上鈣鈦礦顆粒大小差異而影響PL峰值，但仍需進一步實驗確認。以450 nm藍光雷射照射鈣鈦礦/二硫化鉬結構，其中二硫化鉬從單層至6層，發現二硫化鉬PL峰值幾乎沒有變化，但峰值強度有減少的現象。

Perovskite is an emerging solar cell material, and many studies have reported its optoelectronic properties in recent years[1,2], but the surface morphology is rarely mentioned. In a previous study, we found that the perovskite MAPbBr3 could not form a uniform and continuous film on the surface of the iron-palladium alloy, but would present a nanodiscs structure with an exposed alloy metal layer [9]. In our experiment, we found that the insertion of the graphene layer between the perovskite and the ferromagnetic layer enables the perovskite to form a uniform continuous film. The Atomic force microscopy (AFM) profiles show that the roughness of the ferromagnetic layer is less than 1 nm, about 2 nm after transferring graphene, and about 6 nm after spin-coating perovskite. It can be observed from the AFM images and line profile that the perovskite formed a continuous layer on graphene. This technology can be used to prevent short circuits between perovskite and metal layers, and make the device function properly.
Molybdenum disulfide (MoS2) has good carrier mobility and can be used as a semiconductor material, but it has the disadvantage of relatively low light absorption[3]. The perovskite/MoS2 heterostructure has strong light absorption. Although there are many studies on the optoelectronic properties of perovskite/MoS2 structure[4,5], the research on the surface morphology of perovskite on MoS2 is lacking. After we spin-coating perovskite (CsPbBr3) on the MoS2, the shape of MoS2 can still be distinguished in the AFM images, and it can be observed that the perovskite on the MoS2 is denser than that on the substrate. In the analysis of the SEM images, the surface grain size of the perovskite on MoS2 is about 20 nm and on the substrate is about 30 nm. Spin-coating perovskite results in quenching of MoS2 photoluminescence (PL) and a redshift of the peak. Song et al.[4] reported that the quenching is due to charge transfer from perovskite to MoS2, and the redshift is due to the n-type doping effect of quantum dots on MoS2[4]. Moreover, the shape of MoS2 affects the PL peak position of MoS2. After spin-coating, the PL shift of the truncated triangle MoS2 is more than that of the triangle ones, is in the range of 3 to 12 nm, and the shift of the triangle ones is within 3 nm. After spin-coating the perovskite, the PL peak position of the perovskite was measured, and the PL peak of the perovskite on the truncated triangle MoS2 was blue-shifted by 3 to 5 nm compared with the triangle MoS2. A previous study reported that the grain size of the perovskite will affect the PL peak. We speculate that the PL peak may be affected by the difference in the grain size of the perovskite on the triangle and the truncated triangle MoS2, but further experimental confirmation is needed. The perovskite/MoS2 structure was irradiated with a 450 nm blue laser, in which the MoS2 PL peak was almost unchanged from a single layer to 6 layers, but the peak intensity would decrease.

1.Hengmei Cai, Guokun Ma, Yuli He, Li Lu, Jun Zhang, Hao Wang, Ceramics International. 45 (2019) 1150.
2.Feng Chen, Can Zhu, Chunxiang Xu, Peng Fan, Feifei Qin, Gowri Manohari, Junfeng Lu, Zengliang Shi, Qingyu Xu, Anlian Pan, J. Mater. Chem. C. 5 (2017) 7739.
3.Ossila- Molybdenum Disulfide (MoS2): Theory & Applications
(https://www.ossila.com/pages/molybdenum-disulfide-mos2)
4.Xiufeng Song, Xuhai Liu, Dejian Yu, Chengxue Huo, Jianping Ji, Xiaoming Li, Shengli Zhang, Yousheng Zou, Gangyi Zhu, Yongjin Wang, Mingzai Wu, An Xie, and Haibo Zeng, ACS Applied Materials & Interfaces. 10 (2018) 2801.
5.R. Karmakar, D. Sen, D. Mandal, and K. Adarsh, J. Kang, S. Tomasulo, I. Ilev, D. Müller, N. Litchinitser, S. Polyakov, V. Podolskiy, J. Nunn, C. Dorrer, T. Fortier, Q. Gan, and C. Saraceno, eds., OSA Technical Digest, Optical Society of America. JW1A. (2021) 100.
6.Perovskite Mineral Data
(http://webmineral.com/data/Perovskite.shtml#.YdU20GhByMp)
7.Best Research-Cell Efficiency Chart
(https://www.nrel.gov/pv/cell-efficiency.html)
8.Wang, J., Zhang, C., Liu, H. et al., Nat Commun. 10 (2019) 129.
9.Shi-Yu Liu, Zih-En Lin, Bing-Tsun Wu, Ting-Hao Chen, Hsuan-Ching Hung, Chun-Han Yin, Chak-Ming Liu, Po-Chun Chang, Yu-Chiang Chao, and Wen-Chin Lin, submitted to Surfaces and Interfaces (2021).
10.K.S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, Y. Zhang, S.V. Dubonos, I.V. Grigorieva, A.A. Firsov, Science. 306 (2004) 666.
11.X. Huang, X. Qi, F. Boey, H. Zhang, Chem. Soc. Rev. 41 (2012) 666.
12.Y. Lee, J. Kwon, E. Hwang, C. H. Ra, W.J. Yoo, J. H. Ahn, J.H. Park, J.H. Cho, Adv. Mater. 27 (2015) 41.
13.Sefaattin Tongay, Jian Zhou, Can Ataca, Jonathan Liu, Jeong Seuk Kang, Tyler S. Matthews, Long You, Jingbo Li, Jeffrey C. Grossman, and Junqiao Wu, Nano Letters. 13 (2013) 2831.
14.Meric, I., Han, M. Y., Young, A. F., Ozyilmaz, B., Kim, P. & Shepard, K. L., Nature Nanotech. 3 (2008) 654.
15.Radisavljevic, B., Radenovic, A., Brivio, J. et al., Nature Nanotech. 6 (2011) 147.
16.Lopez-Sanchez, O., Lembke, D., Kayci, M. et al. Nature Nanotech. 8 (2013) 497.
17.Sefaattin Tongay, Jian Zhou, Can Ataca, Jonathan Liu, Jeong Seuk Kang, Tyler S. Matthews, Long You, Jingbo Li, Jeffrey C. Grossman, and Junqiao Wu, Nano Letters. 13 (2013) 2831.
18.Kai-Ping Chang, Jer-Chyi Wang, Chang-Hsiao Chen, Lain-Jong Li and Chao-Sung Lai, 2016 13th ICSICT. (2016) 489.
19.Di, J., Li, H., Su, J., Yuan, H., Lin, Z., Zhao, K., Chang, J., Hao, Y., Adv. Sci. (2021) 2103482.
20.Novoselov KS, Geim AK, Morozov SV, Jiang D, Zhang Y, Dubonos SV, Grigorieva IV, Firsov AA, Science. 306 (2004) 666.
21.Armano, Angelo & Agnello, Simonpietro, C. 5 (2019) 67.
22.Jianwei Zhang and Jeff Li, MATEC Web Conf., 100 (2017) 04029.
23.Zhu, Y., Murali, S., Cai, W., Li, X., Suk, J.W., Potts, J.R. and Ruoff, R.S., Adv. Mater. 22 (2010) 3906.
24.Chen, H., Xu, H., Wang, S., Huang, T., Xi, J., Cai, S., ... & Gao, C., Science advances. 3 (2017) 7233.
25.Kim, H., Park, K. Y., Hong, J., & Kang, K., Scientific reports. 4 (2014) 5278
26.Zijun Yi, Najib Haji Ladi, Xuxi Shai, Hao Li, Yan Shen and Mingkui Wang, Nanoscale Adv. 1 (2019) 1276.
27.Shi, E., Gao, Y., Finkenauer, B. P., Akriti, Coffey, A. H., Dou, L., Chem. Soc. Rev. 47 (2018) 6046.
28.Yuan, Z., Shu, Yu., Xin, Y., Ma, B., Chem. Commun. 52 (2016) 3887.
29.Palz, Wolfgang (2010). Power for the World - The Emergence of Electricity from the Sun. Belgium: Pan Stanford. p. 6.
30.Smithsonian MAGAZINE- A Brief History of Solar Panels
(https://www.smithsonianmag.com/sponsored/brief-history-solar-panels-180972006/)
31.B.D.Cullity (1972) Introduction to Magnetic Materials, Addison Wesley, New York.
32.Kock-Yee Law, The Journal of Physical Chemistry Letters 5 (2014) 686
33.Roger Nix (2021) What is UltraHigh Vacuum? Queen Mary, University of London.
34.蘇清森 (2004) 真空技術精華。五南圖書。高雄市。
35.Yongho Seo, Wonho Jhe, Rep. Prog. Phys. 71 (2007) 016101
36.Kohei Yamasue, Takashi Hikihara, Review of Scientific Instruments 77 (2006) 053703.
37.Wang-Kong Tse, A. H. MacDonald. Phys. Rev. B. 84 (2011) 205327
38.Kliger, Lewis, and Randall. (1990) Polarized Light in Optics and Spectroscopy, Academic Press.
39.Pavan M. V. Raja Andrew R. Barron. (2019) Physical Methods in Chemistry and Nano Science.
40.Ewen Smith, Geoffrey Dent. (2005) Modern Raman Spectroscopy–A Practical Approach.
41.K. Xia, W. Wu, M. Zhu, X. Shen, Z. Yin, H. Wang, S. Li, M. Zhang, H. Wang, H. Lu, A. Pan, C. Pan, Y. Zhang, Sci. Bull. 65 (2020) 343.
42.V.Q. Dang, G.S. Han, T.Q. Trung, L.T. Duy, Y.U. Jin, B.U. Hwang, H.S. Jung, N.E. Lee, Carbon. 105 (2016) 353.
43.C.M. Liu, W.H. Wang, P.H. Jiang, W.C. Lin, Nanotech. 30 (2019) 455301.
44.H.P. Chang, E.D. Chu, Y.T. Yeh, Y.C. Wu, F.Y. Lo, W.H. Wang, M.Y. Chern, H.C. Chiu, Langmuir. 33 (2017) 8362.
45.L. Zhang, R. Dillert, D. Bahnemann, M. Vormoor, Energy Environ. Sci. 5 (2012) 7491.
46.S. Kim, H.V. Quy, H.W. Choi, C.W. Bark, Energies. 13 (2020) 1069.
47.Z. Li, Y. Wang, A. Kozbial, G. Shenoy, R. McGinley, P. Ireland, B. Morganstein, A. Kunkel, S.P. Surwade, L. Li, H. Liu, Nat. Materials. 12 (2013) 925.
48.A. Kozbial, Z. Li, C. Conaway, R. McGinley, S. Dhin gra, V. Vahdat, F. Zhou, B. D’Urso, H. Liu, L. Li, Langmuir. 30 (2014) 8598.
49.Guozhu Zhang, Jingwei Wang, Zefei Wu, Run Shi, Wenkai Ouyang, Abbas Amini, Bananakere Nanjegowda Chandrashekar, Ning Wang, and Chun Cheng, ACS Applied Materials & Interfaces. 9 (2017) 763.
50.Fei Chen, Weitao Su, Shichao Zhao, Yanfei Lv, Su Ding, and Li Fu, J. Name. 00 (2012) 1.
51.Tanmay Goswami, Renu Rani, Kiran Shankar Hazra, and Hirendra N. Ghosh, The Journal of Physical Chemistry Letters. 10 (2019) 3057.
52.Tong, Y., Yao, E. P., Manzi, A., Bladt, E., Wang, K., Döblinger, M., Bals, S., Müller-Buschbaum, P., Urban, A. S., Polavarapu, L., Feldmann, J., Adv. Mater. 30 (2018) 1801117.