Effect of Passivation Substrates Surface to CsPbBr3 Quantum Dot Films Optical Stability
ZHAO Hai-xia, WANG Xin-wei*, LI Ru-xue, WANG Deng-kui, FANG Xuan, FANG Dan, WEI Zhi-peng, WANG Xiao-hua
State Key Laboratory of High Power Semiconductor Laser, School of Materials Science and Engineering，Changchun University of Science and Technology, Changchun 130022, China
Abstract：Perovskite quantum dots have been widely studied in the fields of illumination, display, and laser because of excellent luminescence properties, such as high luminous efficiency, narrow-band light emission, and adjustable optical wavelengths. However, the problem of stability of perovskite materials has prevented the application of perovskite photoelectric device. Among them, the perovskite material in the air is easy to decompose and the instability is particularly prominent, seriously affecting its luminescence properties. Therefore, the researchers have tried a variety of methods to improve the stability of perovskite materials. At present, the common way is to introduce some hydrophobic polymer materials (such as POSS, PMMA etc.) into the perovskite nanocrystals or embedded perovskite nanocrystals in mesoporous silica spheres to avoid the exposure of the perovskite nanocrystals to the air and the stability of perovskite material was enhanced effectively. Moreover, the surface of perovskite nanocrystals was passivated, and it was also a common method to improve the optical stability of perovskite. Although these methods can improve the optical stability of the perovskite nanocrystals, their preparation methods are complicated and will introduce other organic functional groups in the perovskite, and surface passivation treatment of perovskite nanocrystals can destroy the original structure of perovskite nanocrystals, which affects the optical properties of the perovskite nanocrystals, which is not conducive to their use in photovoltaic devices. For optical devices silicon (Si), it is a dominant material in today’s photoelectric device industry because of the low cost, large size, and good electrical conductivity. However, The Si has been exposed to the air for a long time, the surface layer is easily to form a hydrophilic silanol group (Si—OH), which will be detrimental to silicon-based perovskite devices stability. So, passivate the Si surface in order to destroy the surface hydrophilic groups (Si—OH) and make the surface from hydrophilic to hydrophobic, to improve the stability of perovskite material in the device. In this study, Use the hydrofluoric acid (HF) treatment for Si surface passivation. It was found that the contact angle of the Si substrate with water after passivation was changed from 50.4° to 87.7°, indicating that the surface of the silicon substrate was changed from hydrophilic to hydrophobic after HF passivation treatment. Field emission scanning electron microscope (FE-SEM) test showed that after the passivation of Si substrate surface is rough, CsPbBr3 QDs film are uniformly dispersed, which is different from the cluster of CsPbBr3 QDs film on the Si substrate surface which is not passivated. The optical properties of CsPbBr3 QDs film at different time were studied by photoluminescence (PL) spectroscopy, and the fitting results of the power-dependent PL measurement confirming the excitonic characteristics is exciton emission because β is 1.12 and 1.203. Through the temperature-dependent PL measurements, it was found that as the temperature rises, the peak energy will gradually have a blueshift because the thermal expansion of the lattice leads to the forbidden gap increases. When the temperature increased from 10 to 300 K, the thermal stability of CsPbBr3 QDs film increased gradually with the increase of passivation time to the Si substrate surface. And the time-dependent PL measurements showed, after HF passivation treatment Si substrate surface, the stability of the CsPbBr3 QDs film gradually increased and the luminescence stability was up to 15 days. Therefore, by simply and effectively passivating the bottom surface of the Si substrate, the hydrophilic groups on the surface can be effectively reduced, improving the Optica stability of the CsPbBr3 QDs film. This provides a new way to enhance the stability of CsPbBr3 QDs film in the application of optoelectronic devices.
赵海霞，王新伟，李如雪，王登魁，方 铉，房 丹，魏志鹏，王晓华. 衬底钝化处理对CsPbBr3量子点薄膜发光稳定性影响[J]. 光谱学与光谱分析, 2019, 39(06): 1706-1710.
ZHAO Hai-xia, WANG Xin-wei, LI Ru-xue, WANG Deng-kui, FANG Xuan, FANG Dan, WEI Zhi-peng, WANG Xiao-hua. Effect of Passivation Substrates Surface to CsPbBr3 Quantum Dot Films Optical Stability. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2019, 39(06): 1706-1710.
[1] Wang H C, Lin S Y, Tang A C, et al. Angewandte Chemie International Edition, 2016, 55(28): 7924.
[2] Li X, Xue Z, Luo D, et al. Science China Materials, 2018, 61(3): 363.
[3] Huang H, Chen B, Wang Z, et al. Chemical Science, 2016, 7(9): 5699.
[4] Pan J, Sarmah S P, Murali B, et al. The Journal of Physical Chemistry Letters, 2015, 6(24): 5027.
[5] Li X, Cao F, Yu D, et al. Small, 2017, 13(9): 1603996.
[6] Huang Shouqiang, Wang B, Zhang Q, et al. Advanced Optical Materials, 2018, 6(6): 1701106.
[7] Liu J, Sheng X, Wu Y, et al. Advanced Optical Materials, 2018, 6(2): 1700897.
[8] Nagashio K, Yamashita T, Nishimura T, et al. Journal of Applied Physics, 2011, 110(2): 024513.
[9] Li J, Xu L, Wang T, et al. Advanced Materials, 2017, 29(5): 1603885.
[10] Garnier P. Solid State Phenomena, 2016, 255: 8.
[11] Nguyen T P, Ozturk A, Park J, et al. Science and Technology of Advanced Materials, 2018, 19(1): 10.
[12] Ai B, Liu C, Deng Z, et al. Physical Chemistry Chemical Physics, 2017, 19(26): 17349.
[13] Wei K, Xu Z, Chen R, et al. Optics Letters, 2016, 41(16): 3821.
[14] Shinde A, Gahlaut R, Mahamuni S. The Journal of Physical Chemistry C, 2017, 121(27): 14872.
[15] Li J, Yuan X, Jing P, et al. RSC Advances, 2016, 6(82): 78311.
[16] Tiep N H, Ku Z, Fan H J. Advanced Energy Materials, 2016, 6(3): 1501420.
