In this work, hybrid heterojunction solar cells are demonstrated based on a conjugate polymer poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) directly spun-cast on micro-textured n-type crystalline silicon wafers. The fabrication conditions suggest that the organic coverage on the micro-textured surface is excellent and key to achieve high efficiency, leading to an average power conversion efficiency of 9.84%. A one-dimensional drift-diffusion model is then developed based on fitting the device characteristics with experimentally determined PEDOT:PSS parameters and projects an ultimate efficiency above 20% for organic/inorganic hybrid photovoltaics. The simulation results reveal the impacts of defect densities, back surface recombination, doping concentration, and band alignment.

Hybrid organic-silicon heterojunction solar cells promise a significant reduction on fabrication costs by avoiding energy-intensive processes. However, their scalability remains challenging without a low-cost transparent electrode. In this work, we present solution-processed silver-nanowire meshes that uniformly cover the microtextured surface of hybrid heterojunction solar cells to enable efficient carrier collection for large device area. We systematically compare the characteristics and device performance with long and short nanowires with an average length/diameter of 30 μm/115 nm and 15 μm/45 nm, respectively, to those with silver metal grids. A remarkable power conversion efficiency of 10.1% is achieved with a device area of 1 × 1 cm 2 under 100 mW/cm 2 of AM1.5G illumination for the hybrid solar cells employing long wires, which represents an enhancement factor of up to 36.5% compared to the metal grid counterpart. The high-quality nanowire network displays an excellent spatial uniformity of photocurrent generation via distributed nanowire meshes and low dependence on efficient charge transport under a high lightinjection condition with increased device area. The capability of silver nanowires as flexible transparent electrodes presents a great opportunity to accelerate the mass deployment of high-efficiency hybrid silicon photovoltaics via simple and rapid soluble processes. KEYWORDS: silver nanowire, solution process, conductive polymer, photovoltaics P hotovoltaic technology is playing an increasingly important role in electricity generation because of rising concerns with petroleum scarcity and green-house gas emissions. Nowadays, crystalline-silicon photovoltaics have a dominant market share for their high efficiency, environmental friendliness, and abundant material supply. 1 However, their energy payback time is still much longer than other thin-film-based technologies, 2 which is largely ascribed to the wafer cost and energy-intensive fabrication processes, such as furnace diffusion (900°C), electrode cofiring (900°C), and high-vacuum chemical deposition (400°C). Consequently, hybrid organic/ silicon solar cells have become an attractive approach in which the device combines the advantages of rapid wet-chemical processes with organic materials and wide absorption range with silicon for the heterojunction formation. 3−7 Among the multiple emerging organic materials, hybrid solar cells based on conductive polymer poly(3,4-ethylenedioxy-thiophene):poly-(styrenesulfonate) (PEDOT:PSS) directly spun-cast on planar or nanostructured silicon surfaces exhibit the most promising performance with a power conversion efficiency (PCE) of approximately 10%. 8−12 A validated device model has further projected that an ultimate efficiency of over 20% is possible with the band alignment of PEDOT:PSS and silicon by controlling interface states, surface reflection, and other factors. 13 Nevertheless, efficient carrier collection presents one of the bottlenecks for the scalability of hybrid devices because of...

Nanostructured crystalline silicon is promising for thin‐silicon photovoltaic devices because of reduced material usage and wafer quality constraint. This paper presents the optical and photovoltaic characteristics of silicon nanohole (SiNH) arrays fabricated using polystyrene nanosphere lithography and reactive‐ion etching (RIE) techniques for large‐area processes. A post‐RIE damage removal etching is subsequently introduced to mitigate the surface recombination issues and also suppress the surface reflection due to modifications in the nanohole sidewall profile, resulting in a 19% increase in the power conversion efficiency. We show that the damage removal etching treatment can effectively recover the carrier lifetime and dark current–voltage characteristics of SiNH solar cells to resemble the planar counterpart without RIE damages. Furthermore, the reflectance spectra exhibit broadband and omnidirectional anti‐reflective properties, where an AM1.5 G spectrum‐weighted reflectance achieves 4.7% for SiNH arrays. Finally, a three‐dimensional optical modeling has also been established to investigate the dimension and wafer thickness dependence of light absorption. We conclude that the SiNH arrays reveal great potential for efficient light harvesting in thin‐silicon photovoltaics with a 95% material reduction compared to a typical cell thickness of 200 µm. Copyright © 2012 John Wiley & Sons, Ltd.

Nano-patterned glass superstrates obtained via a large-area production approach are desirable for antireflection and light trapping in thin-film solar cells. The tapered nanostructures allow a graded refractive index profile between the glass and material interfaces, leading to suppressed surface reflection and increased forward diffraction of light. In this work, we investigate nanostructured glass patterns with different aspect ratios using scalable nanosphere lithography for hydrogenated amorphous silicon (a-Si:H) thin film solar cells. Compared to flat glass cell and Asahi U-type glass cell, enhancements in short-circuit current density (J(sc)) of 51.6% and 8%, respectively, were achieved for a moderate aspect ratio of 0.16. The measured external quantum efficiencies (EQE) spectra confirmed a broadband enhancement due to antireflection and light trapping properties.