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Five groups of silicon wafers were cut from a commercial solar-grade boron-doped Czochralski silicon (Cz-Si) ingot from top to bottom with a certain distance, and made into PERC (passivated emitter and rear cel)) solar cells by using the standard industrial process. Then, as-prepared PERC solar cells were treated by dark annealing (200 °C, 30 min), the 1st LID (45 °C, 1 sun, 12 h), electric-injection regeneration (175 °C, 18 A, 30 min) and the 2nd LID (45 °C, 1 sun, 12 h) in order, and the changes of performance during the process were measured. The results show that the LID (light induced degradation) and regeneration of the PERC solar cells are dominated by those of B-O defects, while dissociation of Fe-B pairs plays a secondary role. The relative degradation rate of 7.03%-9.69% in efficiency during the 1st LID results from the LID caused by B-O defects and the dissociation of Fe-B pairs, while the relative degradation rate of 0.43%-0.81% in efficiency during 2nd LID is solely caused by the dissociation of Fe-B pairs. B-O defects inside PERC solar cells can be completely passivated by the electric injection regeneration, and the passivated B-O defects are stable under the conditions of 2nd LID. PERC solar cells made from the middle of the Czochralski silicon ingot have higher efficiency and open circuit voltage and lower relative degradation rate. In addition, only the spectral response of PERC solar cells in medium and long wavelength range is affected by the LID and regeneration treatment. [ABSTRACT FROM AUTHOR]

In order to study the effect of device structures and silicon wafer positions on light-induced degradation (LID) and regeneration, five groups of industrial PERC and Al-BSF solar cells were fabricated by using silicon wafers from different positions of a B-doped Czochralski silicon (Cz-Si) ingot. Then, the cells were subjected to a dark annealing (200 °C, 30 min), the first LID (45 °C, 1 sun, 12 h), an electrical injection regeneration (175 °C, 18 A, 30 min) and the second LID (45 °C, 1 sun, 12 h) in order, and the variations of performance of the cells with processing time were measured. It was found that after the electrical injection regeneration, the efficiency losses of PERC cells decreased from 1.28–1.76%absolute in the first LID to 0.09–0.16%absolute in the second LID, while those of Al-BSF cells decreased from 0.3–0.66%absolute in the first LID to 0 in the second LID. The efficiency losses of PERC cells during the first LID were caused by the co-action of B-O-defect-induced LID (BO-LID) and dissociation of Fe-B pairs, and the latter contributed 5.81–9.56% of the efficiency loss, while those of Al-BSF cells during the first LID were almost contributed by BO-LID solely. For both kinds of cells, the cells made from the silicon wafers from middle of the ingot had the best performance throughout the experiment. In addition, the LID and regeneration treatments only affected the spectral response of the cells in the wavelength larger than 700 nm. [ABSTRACT FROM AUTHOR]

In this paper, five groups of industrial aluminium back-surface-field (Al-BSF) solar cells were made from silicon wafers from different locations of a B-doped Czochralski silicon ingot. Then, we performed the first LID (45 °C, 1 sun, 12 h), regeneration (100 °C, 1 sun, 24 h), and second LID (45 °C, 1 sun, 12 h) treatments on the cells, and measured the in-situ changes of their I-V characteristic parameters by using an I-V tester during the experiment. The cells were also characterized by Suns-Voc measurement, full-area light beam induced current scanning, and external quantum efficiency measurement at the four breakpoints of treatments (before and after the first LID, after regeneration and the second LID). It was found that the LID and regeneration of the Al-BSF solar cells can be explained by the LID and regeneration reaction of B-O defects and the LID caused by dissociation of Fe-B pairs. After regeneration, the relative decay rate of efficiency decreased from 2.75–3.8% during the first LID to 0.42–1.23% during the second LID, indicating that regeneration treatment (100 °C, 1 sun, 24 h) can improve the anti-LID ability of Al-BSF solar cells. [ABSTRACT FROM AUTHOR]

In order to investigate the light-induced-degradation (LID) and regeneration of industrial PERC solar cells made from different positions of silicon wafers in a silicon ingot, five groups of silicon wafers were cut from a commercial solar-grade boron-doped Czochralski silicon (Cz-Si) ingot from top to bottom with a certain distance and made into PERC solar cells by using the standard industrial process after measuring lifetimes of minority carriers and concentrations of boron, oxygen, carbon, and transition metal impurities. Then, the changes of their I - V characteristic parameters (efficiency η , open-circuit voltage V oc , short-circuit current I sc , and fill factor FF) with time were in situ measured by using a solar cell I - V tester during the 1st LID (45°C, 1 sun, 12 h), regeneration (100°C, 1 sun, 24 h), and 2nd LID (45°C, 1 sun, 12 h). The results show that the LID and regeneration of the PERC solar cells are caused by the transition of B-O defects playing a dominant role together with the dissociation of Fe-B pairs playing a secondary role. The decay of η during the 1st LID is caused by the degradation of V oc , I sc , and FF , while the increase of η during the regeneration is mainly contributed by V oc and FF , and the decay of η during the 2nd LID is mainly induced by the degradation of I sc . After regeneration, the decay rate of η reduces from 4.43%–5.56% (relative) during the 1st LID to 0.33%–1.75% (relative) during the 2nd LID. [ABSTRACT FROM AUTHOR]

In order to improve the photocatalytic performance of TiO 2 and expand its absorption range in the visible light region, depositing noble metals, constructing the p-n heterojunction and controlling the morphology were used to modify TiO 2. First, the TiO 2 photocatalyst with a three-dimensional ordered macroporous structure was prepared by vacuum impregnation combined with calcination, and then the 3DOM Ag/BiOI/TiO 2 composites were successfully prepared by the in-situ deposition and photoreduction. The characterization results show that the composites present a large number of open and transparent pore structures. The pore wall is formed by stacking TiO 2 nanoparticles, with BiOI and Ag nanoparticles evenly distributed on the surface of the pore wall and in the macroporous framework, which expands the specific surface area of 3DOM TiO 2 and provides more active sites for the reaction. The introduction of BiOI and Ag expands the visible light response range and improves the light utilization efficiency. Furthermore, the formation of the Schottky barrier and the internal electric field formed by the p–n heterojunction effectively promotes the interfacial electron transfer and suppress the electron–hole recombination, thereby generating more active species during the photocatalytic process. The experimental results of multi-mode photocatalytic degradation of methyl orange (MO) also show that 3DOM Ag/BiOI/TiO 2 photocatalyst has the best photocatalytic degradation activity. In addition, different samples were tested for hydrogen production by photolysis of water under simulated sunlight conditions, and the results show that 3DOM Ag/BiOI/TiO 2 has the best hydrogen production ability of photolysis of water. The excellent performance of multi-modal photocatalytic degradation of organic pollution and high photohydrogen production activity in 3DOM Ag/BiOI/TiO 2 composites is attributed to the synergistic effect between the introduction of metallic Ag, the unique 3DOM structure, and the p–n heterojunction. [Display omitted] • 3DOM Ag/BiOI/TiO 2 composite was prepared with PS microspheres as the template. • The composite presents a periodic arrangement with uniform pore size. • The formation of p–n heterojunction reduces the recombination of electron–hole pairs. • Schottky barrier formed between Ag and semiconductor further promotes the separation of photogenerated carriers. [ABSTRACT FROM AUTHOR]