Design optimization of highly efficient spectrum-splitting and beam-concentrating diffractive optical element for lateral multijunction solar cells

Abstract

Design optimization of highly efficient spectrum-splitting and beam-concentrating diffractive optical element for lateral multijunction solar cells * Wang Jin-Ze(王进泽) a)b) , Ye Jia-Sheng(叶佳声) c) , Huang Qing-Li(黄庆礼) a)b) , Xu Xin(许 信) a)b) , Li Dong-Mei(李冬梅) a)b) , Meng Qing-Bo(孟庆波) a)b) † , and Yang Guo-Zhen (杨国桢) d) ‡

Realizing high photovoltaic efficiency with parallel multijunction solar cells based on spectrum-splitting and -concentrating diffractive optical element

“…Firstly, the size of this special DOE is 20.0 mm×40.0 mm, with a total maximum thickness of 910.0 µm, which can be optimized and attenuated to facilitate the fabrications and applications. For instance, if y 1m is too big, the focal lens in the Y direction can be manufactured at the other side of the DOE separately to reduce the difficulty in fabrication, and h 1 (x 1 ) can be attenuated with thickness optimization algorithms [23,33] (see supporting information for discussion of controlling the thickness optimization by applying the thickness optimization algorithms). Besides, according to the basic knowledge of phase modulation, we can use a reflective DOE structure to replace the aforementioned refractive DOE.…”

“…To facilitate the fabrication of the prototype of the DOE in our lab, we have proposed a thickness optimization algorithm to attenuate h x (x 1 ) to a reasonable value [22,23,33] while still maintaining the functions of spectrum-splitting and concentrating ( Fig. S1 in Supporting information).…”

“…S1 and S2), f is the focal length of the lens, λ 0 is chosen as the average wavelength considering the wavelength range, β is the angle of the refractive blazed grating, and d is the grating constant which is chosen to be λ 0 cot(β )/(n − 1) so that most energy of wavelength λ 0 is diffracted into its first-order diffraction, as shown in Fig. 1 To facilitate the fabrication of the prototype of the DOE in our lab, we have proposed a thickness optimization algorithm to attenuate h x (x 1 ) to a reasonable value [22,23,33] while still maintaining the functions of spectrum-splitting and concentrating (Fig. S1 in Supporting information).…”

Spectrum-Splitting Diffractive Optical Element of High Concentration Factor and High Optical Efficiency for Three-Junction Photovoltaics

“…In this Letter, a three-bandgap DOE with a high concentration factor has been designed and fabricated by five-circle micro-fabrication according to the design principles and the optimization algorithm in our previous works. [18,19] The light is efficiently split into three sub-spectrum ranges by our as-fabricated DOE and strongly concentrated on the focal plane. The system concentration factor reaches 12×.…”

“…1(a)), the design principles and optimization algorithm are applied as described in Refs. [18,19]. For three-junction photovoltaic applications, the whole diffractive spectrum is divided into three sub-spectrum ranges, which can be absorbed by three spectrum-matching solar cells.…”