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Hybrid PEDOT:PSS-silicon heterojunction solar cells have the advantages of low temperature, low cost and solution process. However, as a low-quality native oxide layer can easily form on the surface of silicon substrates, the hybrid solar cells still suffer from charged carrier recombination at the defective interface, hence affecting the device characteristics. In this work, we employ a thermally induced silicon hydrosilylation technique to form a self-assembled monolayer(SAM) on the hydrogen-terminated silicon substrate, in order to prevent the oxidation and passivate the surface of silicon. The quality of this monolayer passivation is characterized by the contact angle, X-ray photoelectron spectroscopy (XPS) analyses. We have found that the SAM passivation can effectively reduce the contact resistance between silicon and the aluminum electrode, leading to an improved open-circuit voltage and fill-factor. However, as the silicon surface with the SAM passivation becomes hydrophobic, it is difficult to apply aqueous PEDOT:PSS solution onto silicon. Therefore, we further apply a low-damage oxygen plasma treatment to modify the terminal functional group of the monolayer to form a hydrophilic surface. The power conversion efficiency of the modified devices is between 10–12%. Although the PCE does not surpass the reference device due to possible chemical reactions between the PEDOT:PSS and SAM, the proposed low- damage oxygen-plasma treatment provide a viable solution for modifying the functional passivation of hybrid PEDOT:PSS silicon solar cells using SAMs.

The dopant-free carrier selective contacts (CSC) to replace the complex diffusion manufacturing are increasingly explored using a variety of different materials. In this work, we investigate various organic materials, including conductive polymer PEDOT: PSS, fluorescent polymers PFO and Green B, and small molecules DMFL-NPB, to serve as the hole selective con-tact (HSC). By analyzing the lifetime and implied open-circuit voltage, assessing of contact resistivity and band alignment, as well as the device efficiency, we evaluate the potential of soluble organic materials acting as the HSC. The results have shown that PEDOT: PSS could effectively passivate the silicon surface to increases the open-circuit voltage by 31 mV and the short-circuit current density by 2.9 mA/cm2. Overall, the power conversion efficiency increases from 12.36% to 14.55%.

In this work, we use the metal-assisted chemical etching (MACE) to produce our multi-scale surface textures, namely “Hierarchical structure”, which is combined with micropyramid and nanowires. The templates are modulated through controlling the morphology of silver cluster on the randomly distributed micro-pyramidal surface with rapid thermal annealing (RTA) and the ratio of hydrogen fluoride (HF) and hydrogen peroxide (H 2 O 2 ) during metal-assisted chemical etching. The power conversion efficiency (PCE) of new multi-structure on a hybrid solar cell can achieve 14.07 % by reducing reflectance to 3.61 % and enhancing J SC to 33.43 mA/cm2 with a 1x1 cm2 active area.

In this work, we demonstrate the packaging of hybrid organic - silicon solar cell mini-modules employing flexible and ultrathin transparent conductive films. The unique engineering plastic substrates are printed with high-resolution, micrometer-scaled silver meshes to achieve superior optical transmittance and low sheet resistance, offering the efficient collection of charged carriers through distributed metallic grids. The width of silver grid can be as low as 3 μm, which is a 10 to 15 fold reduction compared to the conventional grid width used in screen printing. By systematically comparing various substrate materials and process conditions, we achieve a power conversion efficiency of 9.5% on 2x2 cm2 mini-modules.