Preparation of Anti-reflection Coatings with Hollow Silica Nanoparticles by Self-assembly

doi:10.15541/jim20130632

Abstract

Abstract:

Using tetraethyl orthosilicate (TEOS) as raw material and polyacrylic acid (PAA) as nucleating material, hollow silica nanoparticles were synthesized on the basis of traditional method of Stöber. Using hollow silica nanoparticles, both single-layer anti-reflection coatings and broad-band double-layer anti-reflection coatings were prepared by self-assembly. The structure control of the hollow silica nanoparticles, the effect of deposition cycle, pH value of the hollow silica nanoparticle dispersion on transmittance of coatings, and the preparation of the double-layer anti-reflection coatings with a graded-refractive-index were investigated. The results show that the size and void fraction of the hollow silica nanoparticles can be controlled precisely by changing the amount of PAA and TEOS. The thickness and refractive index of the anti-reflection coatings can also be tuned accurately in the same way. The deposition cycles are reduced from 10 cycles to 2 cycles by acid pickling which simplifies the coating process. This new technique significantly increases the transmittance of glass substrate coated by single-layer anti-reflection coatings in the range of 350-800 nm under optimum conditions, and improves the maximum transmittance from 91.6% to 98.1% at optimized wavelength (λ=520 nm). Furthermore, glass substrate coated by double-layer anti-reflection coatings can increase the transmittance more than 5% in a much wider wavelength range (400-1500 nm).

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Key words: hollow silica nanoparticle, anti-reflection coating, transmittance, self-assembly

CLC Number:

TQ127

SUN Zhi-Juan, CHEN Xue-Lian, JIANG Chun-Yue. Preparation of Anti-reflection Coatings with Hollow Silica Nanoparticles by Self-assembly[J]. Journal of Inorganic Materials, 2014, 29(9): 947-955.

Figures/Tables 11

Table 1 Experimental design of the preparation of hollow silica nanoparticles

Run	Amount of ammonia/mL	Amount of PAA /g	Amount of TEOS /mL
1	4.50	0.75	3.50
2	6.75	0.75	3.50
3	9.00	0.75	3.50
4	6.75	0.60	1.30
5	6.75	0.80	1.75
6	6.75	1.00	2.20
7	6.75	0.90	6.00
8	6.75	0.90	5.00
9	6.75	0.90	4.00
10	6.75	0.90	3.00
11	6.75	0.90	2.00

Fig. 1 TEM images of hollow silica nanoparticles with ammonia amount of 4.50 mL (a), 6.75 mL (b) and 9.00 mL (c)

Fig. 2 TEM images and particle size distributions of hollow silica nanoparticles with various amount of PAA (a, b) PAA/TEOS=0.60 g/1.30 mL; (c, d) PAA/TEOS=0.80 g/1.75 mL; (e, f) PAA/TEOS=1.00 g/2.20 mL

Fig. 3 TEM images of hollow silica nanoparticles with TEOS amount of 6.00 mL(a), 5.00 mL(b), 4.00 mL(c), 3.00 mL(d) and 2.00 mL(e), and the curve of relation between the amount of TEOS and the void fraction (f)

Fig. 4 Effect of acid pickling on deposition cycles

Fig. 5 SEM images of the single-layer anti-reflection coatings by no acid pickling (a, b) and acid pickling(c, d)

Fig. 6 Effect of deposition cycle on the transmittance of the coatings

Fig. 7 SEM images of the single-layer anti-reflection coatings with various deposition cycles (a, b) Coating 1 time; (c, d) Coating 2 times; (e, f) Coating 3 times

Fig. 8 Effect of pH value of the hollow silica nanoparticle dispersion on the transmittance of the coatings

Table 2 The specific property parameters of single-layer anti-reflection coatings

Sample	Hollow silica nanoparticles dispersion pH	Thickness of the coatings / nm	Refractive index of the coatings	Optimized wavelength / nm	Maximum transmittance / %
1	1.5	72	1.18	475	95.3
2	2.5	101	1.23	520	98.1
3	3.0	96	1.22	510	97.4
4	3.5	91	1.21	505	96.8
5	4.5	79	1.20	495	96.2

Fig. 9 Transmittance of both double-and single-anti-reflection coatings (a) Transmittance; (b) Increased amount of transmittance

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