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We report an application of a pulsed ultraviolet (UV) laser (λ = 355 nm) in producing translucent Si solar cells. This process efficiently generates a densely packed microhole array on a fully fabricated Si P‐N junction solar cell in just a few minutes. Herein, prototype cells with a nominal microhole diameter of 23 μm with a spacing between 60 and 300 μm are fabricated. High‐resolution electron‐beam microscopy reveals that the UV laser beam introduces amorphized silicon oxide (SiO_x) in proximity to the patterned microholes via localized heating in air. Quantitative photovoltaic (PV) analysis shows a decline in the open‐circuit voltage (V_oc) and the fill factor (FF) of the cells with the increase in the microhole density, likely due to the P‐N junction damage during the laser beam irradiation. Despite the reduction inV_ocand FF, the solar cells retain a short‐circuit current density (J_sc) above 90% without post‐processing. The inherent microhole geometry associated with the laser beam profile allows multiple light scattering within the confined microhole structure, enhancing the translucency of the cells. While further development is required for optimization, these findings support the potential use of UV laser beams for fast and scalable production of translucent solar cells. 

Microstructural properties of thin-film absorber layers play a vital role in developing high-performance solar cells. Scanning probe microscopy is frequently used for measuring spatially inhomogeneous properties of thin-film solar cells. While powerful, the nanoscale probe can be sensitive to the roughness of samples, introducing convoluted signals and unintended artifacts into the measurement. Here, we apply a glancing-angle focused ion beam (FIB) technique to reduce the surface roughness of CdTe while preserving the subsurface optoelectronic properties of the solar cells. We compare the nanoscale optoelectronic properties “before” and “after” the FIB polishing. Simultaneously collected Kelvin-probe force microscopy (KPFM) and atomic force microscopy (AFM) images show that the contact potential difference (CPD) of CdTe pristine (peak-to-valley roughness > 600 nm) follows the topography. In contrast, the CPD map of polished CdTe (< 20 nm) is independent of the surface roughness. We demonstrate the smooth CdTe surface also enables high-resolution photoluminescence (PL) imaging at a resolution much smaller than individual grains (< 1 μm). Our finite-difference time-domain (FDTD) simulations illustrate how the local light excitation interacts with CdTe surfaces. Our work supports low-angle FIB polishing can be beneficial in studying buried sub-microstructural properties of thin-film solar cells with care for possible ion-beam damage near the surface. 

Rapid progress has been achieved in thin film CdTe solar cells, reaching a power conversion efficiency of 22.1 %. Researchers demonstrated a short-circuit current density (Jsc) of ≈ 31 mA/cm2 and a fill factor (FF) of ≈ 79 %, close to the theoretically calculated maximum values. However, the open-circuit voltage (Voc) remains below 0.9 V, much lower than the estimated Voc of 1.2 V. One strategy to improve the Voc is to implement a passivated back-contact on CdTe that can reduce the recombination by repelling minority carriers at the surface (i.e., electrons in CdTe). An aluminum oxide thin film (Al2O3) is an attractive candidate owing to its innate fixed negative charges (1012 ~ 1013 cm-2). Here, we use a patterned Al2O3 layer on CdTe to produce PERC-like CdTe solar cells (CdTe PERC). 

Rapid progress has been achieved in perovskite solar cells, improving the efficiency from 3.8 % to 25.7 % in less than a decade. However, the stability of perovskites still need to be improved before commercialization. This study reports the thermal stability of perovskites exposed to an ion beam irradiation. Such combined stressors are seen in atomic/nanoscale microscopy, where a perovskite lamella is characterized using a controlled heating/cooling stage. Focused ion beams (FIBs) are frequently used to section perovskites of interest. Previous studies proposed that high-energy electron beams could cause unexpectedly fast thermal degradation. Alternatively, the perovskite surface may be already altered during FIB processes, accelerating the deterioration. Here, we use a grazing angle argon ion (Ar+) beam directly irradiated on methyl-ammonium lead iodide (MAPbI3) to test the impact of ion beams to degradation mechanisms.