Towards high‐efficiency multi‐junction solar cells with biologically inspired nanosurfaces

Abstract

Multi‐junction solar cells offer extremely high power conversion efficiency with minimal semiconductor material usage, and hence are promising for large‐scale electricity generation. However, suppressing optical reflection in the UV regime is particularly challenging due to the lack of adequate dielectric materials. In this work, bio‐inspired antireflective structures are demonstrated on a monolithically grown Ga0.5In0.5P/In0.01Ga0.99As/Ge triple‐junction solar cell, which overcome the limited optical response of reference devices. The fabricated device also exhibits omni‐directional enhancement of photocurrent and power conversion efficiency, offering a viable solution to concentrated illumination with large angles of incidence. A comprehensive design scheme is further developed to tailor the reflectance spectrum for maximum photocurrent output of tandem cells. Copyright © 2012 John Wiley & Sons, Ltd.

Sub-50-nm self-assembled nanotextures for enhanced broadband antireflection in silicon solar cells

“…The most straightforward approach places a single layer of intermediate optical index at the interface to create destructive interference in the reflected light, providing full antireflection at a single wavelength, l ¼ 4n i Á t, with material thickness (t) and refractive index n i ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffi n S Á n A p , where n S and n A are the refractive indices of the substrate and air, respectively. Increasing broadband coverage, for application in transparent window coatings [2][3][4][5] , military camouflage 6 or solar cells [7][8][9][10][11][12][13][14][15] , is possible using thin-film multilayer schemes 16 . An alternative to thin-film-coating strategies instead patterns the interface at subwavelength dimensions, creating an effective medium between the substrate and air, with n i changing gradually from n A to n S 10,11,17 .…”

A comprehensive review on bioinspired solar photovoltaic cells

“…Bamboo, SiO 2 Leaf Self-cleaning ability of solar cells 39 Synthetic polymers Butterfly Light absorption in solar cells 40 Polyacrylamide hydrogel Natural dyes Natural pigments for DSSC 42,43 Silicon Human eyes, dipteran Light absorption as Si funnel arrays BCL 44,46 Ruthenium (II)-polypyridyl Ruthenium Transient absorption and fluorescence lifetime [50][51][52][53] Shape memory polymers Origami Space applications of solar cells 54 Graphene … High transparency (97.7%), low reflectivity and higher energy (20%) conversion 55 Multijunction solar cells … High PCE [56][57][58][59][60][61] process and need for an integrated knowledge in diverse fields of biology, quantum, nano, and physics for the effective development of new bioinspired applications. The sustained efforts are rendered by the scientific community to simulate and apply the developed techniques in electric power generation through PV semiconductor cells for a full prevailing range of ultraviolet, infrared, tropical, and temperate conditions with varying ambient temperatures.…”

“…While locating metamorphic and lattice matched triple‐junction solar cells under concentrated illumination, an achieved higher efficiency of about 43.5% was recorded . Yu et al demonstrated the amalgamation of bioinspired antireflective structures into a monolithically grown triple‐junction solar cell Ga0.5In0.5P/In0.01Ga0.99As/Ge. The moth‐eye structures served as an inspiration for these multijunction solar cells with a pitch of about 600 nm and depth of about 900 nm, which resulted in the overall increase of ultraviolet reflection of about 35% at 300‐nm wavelength.…”

Light trapping in thin-film solar cells via scattering by nanostructured antireflection coatings

“…[1][2][3][4][5][6][7][8] For optimal overall device performance, the structures required for light trapping must generally be integrated with antireflection coatings present on the top surface of the solar cell and this can severely constrain the incorporation of light trapping structures on the top surface of a thin-film photovoltaic device. However, the advent of nanostructured antireflection coatings, which can provide broadspectrum, wide-angle antireflection functionality, [9][10][11][12][13][14] offers an opportunity to achieve both antireflection and light trapping (scattering) functionality simultaneously with a single, appropriately designed, nanostructured layer at the device surface.…”