Printable Nanostructured Silicon Solar Cells for High-Performance, Large-Area Flexible Photovoltaics

Abstract

Nanostructured forms of crystalline silicon represent an attractive materials building block for photovoltaics due to their potential benefits to significantly reduce the consumption of active materials, relax the requirement of materials purity for high performance, and hence achieve greatly improved levelized cost of energy. Despite successful demonstrations for their concepts over the past decade, however, the practical application of nanostructured silicon solar cells for large-scale implementation has been hampered by many existing challenges associated with the consumption of the entire wafer or expensive source materials, difficulties to precisely control materials properties and doping characteristics, or restrictions on substrate materials and scalability. Here we present a highly integrable materials platform of nanostructured silicon solar cells that can overcome these limitations. Ultrathin silicon solar microcells integrated with engineered photonic nanostructures are fabricated directly from wafer-based source materials in configurations that can lower the materials cost and can be compatible with deterministic assembly procedures to allow programmable, large-scale distribution, unlimited choices of module substrates, as well as lightweight, mechanically compliant constructions. Systematic studies on optical and electrical properties, photovoltaic performance in experiments, as well as numerical modeling elucidate important design rules for nanoscale photon management with ultrathin, nanostructured silicon solar cells and their interconnected, mechanically flexible modules, where we demonstrate 12.4% solar-to-electric energy conversion efficiency for printed ultrathin (∼ 8 μm) nanostructured silicon solar cells when configured with near-optimal designs of rear-surface nanoposts, antireflection coating, and back-surface reflector.

High‐Performance Flexible Nanostructured Silicon Solar Modules with Plasmonically Engineered Upconversion Medium

“…[ 1,2 ] Advantages including reduced materials consumption, relaxed requirements of materials purity, and ability to form large-area devices on unlimited classes of module substrates make them particularly useful as building blocks for realizing high-effi ciency, low-cost photovoltaic systems. [ 6,7 ] While light trapping methods based on various diffractive and/ or refl ective optical elements can greatly help to improve the absorption of optically thin silicon, [8][9][10][11][12][13] complementary means to additionally capitalize on such low energy photons are desirable to further improve the performance of ultrathin silicon solar cells. [ 6,7 ] While light trapping methods based on various diffractive and/ or refl ective optical elements can greatly help to improve the absorption of optically thin silicon, [8][9][10][11][12][13] complementary means to additionally capitalize on such low energy photons are desirable to further improve the performance of ultrathin silicon solar cells.…”

High performance ultrathin silicon solar microcells enabled with nanophotonic light management and spectral upconversion

“…4 shows current density (J)-voltage (V) curves measured from individual ultrathin (~8 µm) microcells of bare and nanostructured (period = ~500 nm, diameter = ~350 nm, height = ~140 nm) silicon printed on a SU-8-coated glass substrate without any reflective element or a plasmonically engineered upconversion medium (i.e., UCNC-coated Ag hybrid nanostructures), in which thermally curable silicone was used as an adhesive and planarizing layer. The nanostructured silicon was implemented with optimal geometric parameters of silicon nanoposts to maximize the absorption of the incident solar light [10]. The solar-to-electric energy conversion efficiency of the nanostructured microcells on a SU-8-coated glass substrate (green) was improved by ~52% compared to the bare silicon devices (blue) due to the effects of anti-reflection, diffraction, and light-trapping provided by the front-surface photonic nanostructures.…”

“…1) were performed based on previously reported procedures [10]. Briefly, the process starts from the formation of the hexagonal Cr islands (period = 500 nm) on p-type silicon (111) wafer by softimprint lithography, oxygen reactive ion etching, and electron-beam evaporation of Cr.…”

“…In this regard, methods to increase the absorption and thus improve the performance of optically thin silicon solar cells have been the focus of extensive research efforts over the past decade [6]. Although the introduction of various photonic nanostructures provided significant enhancements of the absorption in optically thin silicon solar cells by synergistic effects of antireflection, diffraction, and light-trapping [7]- [10], their performance can be further boosted by improving the absorption in the longer wavelength range near the bandgap. Here we present an approach that can improve the absorption of above-bandgap low-energy photons for ultrathin, nanostructured silicon solar cells by exploiting plasmonically enhanced spectral upconversion in conjunction with printingbased deterministic materials assemblies.…”

Evolution mechanism of mesoporous silicon nanopillars grown by metal-assisted chemical etching and nanosphere lithography: correlation of Raman spectra and red photoluminescence

“…Silicon nanostructures, including nanowires and nanopillars, are one of the most promising materials for applications in nanoscale electronics [1,2], photovoltaics and energy conversion [3][4][5], energy storage [6], optoelectronics [7,8], nanocapacitor arrays [9], biosensors [10,11], to name a few. Several studies on silicon nanostructures have been well documented over the last decade [12].…”