Soft-Microstructured Transparent Electrodes for Photonic-Enhanced Flexible Solar Cells

Abstract

Microstructured transparent conductive oxides (TCOs) have shown great potential as photonic electrodes in photovoltaic (PV) applications, providing both optical and electrical improvements in the solar cells’ performance due to: (1) strong light trapping effects that enhance broadband light absorption in PV material and (2) the reduced sheet resistance of the front illuminated contact. This work developed a method for the fabrication and optimization of wavelength-sized indium zinc oxide (IZO) microstructures, which were soft-patterned on flexible indium tin oxide (ITO)-coated poly(ethylene terephthalate) (PET) substrates via a simple, low-cost, versatile, and highly scalable colloidal lithography process. Using this method, the ITO-coated PET substrates patterned with IZO micro-meshes provided improved transparent electrodes endowed with strong light interaction effects—namely, a pronounced light scattering performance (diffuse transmittance up to ~50%). In addition, the photonic-structured IZO mesh allowed a higher volume of TCO material in the electrode while maintaining the desired transparency, which led to a sheet resistance reduction (by ~30%), thereby providing further electrical benefits due to the improvement of the contact conductance. The results reported herein pave the way for a new class of photonic transparent electrodes endowed with mechanical flexibility that offer strong potential not only as advanced front contacts for thin-film bendable solar cells but also for a much broader range of optoelectronic applications.

Photonic-Structured Perovskite Solar Cells: Detailed Optoelectronic Analysis

“…These structures have also been shown to provide a broad angular acceptance, which is paramount for the proper functioning of the devices under bending conditions . In terms of manufacturability, the studied geometry of semi-spheroidal features in a hexagonal (honeycomb) array mimics the photonic designs that can be fabricated by industrially attractive micro-patterning methods, such as colloidal lithography (CL)a low-cost soft-lithography process capable of engineering the optical schemes with nano-/micrometer resolution with high uniformity in a highly scalable manner. − …”

Optically-boosted planar IBC Solar Cells with Electrically-harmless Photonic Nanocoatings

“…The colloidal lithography (CL) procedure applied in this work involves the four main steps described below and further detailed in previous contributions of the authors. 18,22 The first step consists in depositing a self-assembled and highly-ordered close-packed monoarray (acting as the lithographic mask) of colloidal polystyrene micro-spheres (1.3 m diameter) through Langmuir-Blodgett (LB) on the surface of the sample. Fig.…”

“…Nevertheless, the optical performance within the wavelength range of interest (350-1400 nm) is not affected by these residues. 22 The main parameters of the CL process investigated in this work and their effects on the final structures are listed in the Methods section. To design high-aspect ratio features, matches the equivalent film thickness since the deposited material thickness is inferior to the radius of the masking colloids.…”

“…Such drawback is circumvented with the CL-patterned top coatings here developed, since they avoid structuring the PV layers while providing strong LT. Also, our methodology can be applied on a wide range of PV absorbers, not being limited solely to c-Si. 1,21,22,29 O2 𝑡 𝑅𝐼𝐸 = 350 s). The "4n 2 " spectra correspond to the theoretical ideal absorption in the Lambertian formalism.…”

Understanding the Potential of Light Absorption in Dots-in-Host Semiconductors

“…In particular, PbS CQDs have been shown to have excellent structural compatibility with perovskite host materials, [3,20,21] with the latter also showing amazing optoelectronic properties that granted perovskite solar cells incredible e ciencies reaching 25.6%, [22][23][24][25] thus underlining a path worth exploring for QD@Host applications. Furthermore, combining these QD@Host absorbers with advanced light-trapping (LT) techniques, [26][27][28][29][30] could pave the way for highly e cient, yet exible PV technologyan important market driver. [31][32][33] Detailed models of the optical behaviour of QD@Host semiconductors are thus fundamental to accompany the technological developments.…”