In the field of solar cell technology, the conversion efficiency of silicon heterojunction (SHJ) solar cells has reached 27.08%. Meanwhile, perovskite/SHJ tandem solar cells based on this structure have achieved an efficiency of 34.85%, exceeding the theoretical limit of 33.7% for single-junction devices. In the industry transitions from single-junction to tandem configurations, SHJ cells, due to their unique structure and low-temperature fabrication process, exhibit superior compatibility with perovskite layers. This makes SHJ technology play a critical role in the development of perovskite/tandem solar cells. The application of high-performance silver-coated copper (Cu@Ag) paste to electrode metallization provides a feasible method to reduce the costs and improve the performance of SHJ cells. However, the micron-scale particle size of Cu@Ag powder (typically several micrometers) limits the packing density of the electrode layer. To address this, nano-silver powder (about 100 nm) is commonly used as an additive, which enhances both the packing density of the powder and the electrical conductivity through nano-effects. Although many studies focus on isolated aspects such as paste conductivity, a systematic evaluation covering contact resistivity, printed and cured electrode morphology, overall cell performance, and long-term stability remains scarce. Potential adverse effects of nano-silver addition have also been overlooked. Therefore, a thorough investigation on the role of nano-silver in low-temperature Cu@Ag pastes is necessary. Highly conductive low-temperature curing pastes generally use binary or ternary composite powders with well-separated particle sizes to achieve high packing density according to the dense packing theory. In this work, we systematically adjust the proportions of three conductive powders: micro-sized Cu@Ag (3-5 mu m), sub-micron silver (500 nm), and nano-silver (100 nm), to study the effects of nano-silver on key properties of Cu@Ag paste. These include curing temperature and sintering behavior, microstructure of cured electrodes, interface structure between electrodes and the silicon wafer, electrical resistivity, and the overall conversion efficiency of SHJ solar cells. The aim is to clarify the underlying mechanisms and optimize the nano-silver content. This research reveals several significant influences of nano-silver addition on Cu@Ag paste properties. 1) It markedly reduces the resistivity of the cured electrode. Compared with sub-micron silver, nano-silver facilitates improved lateral conductivity at lower sintering temperatures. 2) It introduces additional pores at the contact interface with the silicon wafer, thereby increasing contact resistivity. A thickened organic layer at the interface also forms, which reduces the open-circuit voltage of the cell. 3) It enhances paste thixotropy, resulting in narrower printed electrode lines to reduce shading loss and increase short-circuit current density. At the same time, it raises electrode height and cross-sectional area, which helps improve the fill factor. 4) When the nano-silver content is controlled at 15%, the efficiency of SHJ cells is comparable or close to that of reference cells with pure silver electrodes, mainly due to the improvement of fill factor and short-circuit current density. In summary, an optimized amount of nano-silver powder (e.g., 15%) can simultaneously enhance electrode conductivity, printability, and opto-electrical performance, resulting in SHJ cells with efficiency comparable to those using pure silver electrodes. This demonstrates the potential of Cu@Ag pastes as a cost-effective alternative without compromising performance. Future studies should focus on the long-term reliability of such paste and its scalability, which will support the mass adoption of this technology in various tandem solar cells.

A simplified two-step H 3 PO 4 /NaOH process enables high-value recovery of Ag and Si from c-Si cells. It reduces etchant use and toxic waste, boosting eco-efficiency and demonstrating advances in simplicity, purity, and universality.

Against the backdrop of persistently high silver price, silver paste further intensifies cost pressure on crystalline silicon and tandem solar cells. There is an urgent need to develop low-silver or silver-free conductive pastes with reduced cost to achieve the dual objectives of cost reduction and efficiency enhancement in solar cells. Among the available strategies, replacing silver powder with silver-coated copper powder currently represents one of the most effective cost-reduction approaches for conductive pastes. Silver-coated copper paste not only delivers electrical performance comparable to that of conventional silver paste but also substantially lowers material cost due to its reduced silver content. Moreover, it demonstrates superior resistance to continuous oxidation and enhanced long-term reliability. Consequently, it has emerged as a key material for the metallization of both crystalline silicon and tandem solar cells. Silver-coated copper powder typically comprises spherical microparticles with the particle size ranging from 1.0 to 7.0 mu m and exhibits high packing porosity. Therefore, achieving optimal conductivity requires the incorporation of submicron silver powder to improve particle packing density and nano-silver powder to facilitate low-temperature sintering. However, driven by the industry-wide trend toward silver reduction, identifying viable alternatives to nano-silver powder is critically important for further cost-effective optimization of paste performance. Conductive nano-oxide powders possess high surface energy, high electrical conductivity, high melting and boiling points, and low shrinkage, rendering them promising candidates to replace the nano-silver powder. Nano-antimony tin oxide (ATO) powder, as a representative n-type semiconductor material, shares the same semiconductor type as the window layer in SHJ (silicon heterojunction) or tandem solar cells. It readily forms ohmic contacts when interfaced with either silver-coated copper powder or silver powder and exhibits low resistivity. Compared with costly nano-silver powder, its cost-effectiveness is particularly pronounced. This study aims to enhance the sintering behavior and conductivity of low-temperature silver-coated copper paste through the addition of high-surface-energy nano-ATO powder. Using SHJ solar cells as the test platform, the application effects and underlying mechanisms are systematically investigated. The impact of nano-ATO is evaluated with respect to the paste's thermodynamic properties, rheological behavior, electrical performance, and corresponding solar cell performance. The main findings are as follows: 1) When the ATO content is <= 1.5%, it effectively lowers the volatilization temperature of solvents during the curing process, minimizes solvent residue, and thereby promotes both powder sintering and resin curing. 2) As the ATO content increases, key rheological properties of the paste-including thixotropy, yield stress, and elastic modulus are enhanced. The static paste structure is reinforced, which helps suppress sagging and enables the printing of narrower, more stable line widths. 3) The bulk resistivity of the paste initially decreases and subsequently increases with rising ATO content, whereas the contact resistivity between the electrode and the substrate continues to decline as ATO content increases. 4) ATO powder reduces the accumulation of organic resin at the contact interface, thereby improving the open-circuit voltage. Additionally, it facilitates the formation of finer grid lines, which enhances the short-circuit current. The series resistance of the solar cell first decreases and then increases with increasing ATO content. Driven by the synergistic effects of these factors, the efficiency of the SHJ solar cell peaks at an ATO addition of 1% (mass fraction), achieving a relative improvement of 0.485% compared with that of the conventional solar cell prepared with silver paste. This demonstrates that an optimal amount of nano-ATO powder can effectively enhance the overall conductivity of the paste, thereby significantly improving the comprehensive performance of the solar cell.

Titanium carbide (TiCx) thin films were fabricated by radio frequency magnetron sputtering to study their photovoltaic properties. The dense crystalline TiCx thin films with bandgap and work function of 2.9 eV and 4.3 eV were prepared. The energy band distribution of heterojunction solar cells with different carrier concentrations and work functions of transparent conductive films was simulated by AFORS-HET software. The highperformance solar cell will be achieved by reducing the work function of transparent conductive oxides and increasing the carrier concentration in the TiCx layer. Finally, TiCx thin films substrate temperature and postannealing effect on the minority carrier lifetime of n-type monocrystalline silicon wafers with a-Si:H(i) and aSiOx:H(i) passivation layers were studied.

The structural, electrical and optical properties of molybdenum oxide (MoOx) thin films prepared by magnetron sputtering are studied with annealing temperature. The interface properties of silicon with the intrinsic amorphous silicon (a-Si:H(i)) and alumina (AlOx) passivation layers are investigated by the minority carrier lifetime and implied-Voc(iVoc). The AlOx shows the better passivation properties and thermal stability for the carrier- selective contact solar cells. The Ce-doped In2O3(ICO) is deposited on the surface of MoOx thin films. It is found that the optimized annealing temperature is 125 degrees C for the carrier selective contact solar cells with the aSi:H(i) passivation layer. It could increase to 175 degrees C for the AlOx passivation layer.

In this study, we investigated the effect of H2O partial pressure on the chemical characteristic and optoelectrical properties of the indium tin oxide (ITO) films and the performance and stability of heterojunction (HJT) solar cells. The H2O with varying partial pressure from 2.72 x 10(-5) Pa to 8.38 x 10(-5) Pa is obtained from the residual gas in the magnetron sputtering device chamber. With the H2O partial pressure raises, the resistivity of ITO films increases from 3.6 x 10(-4) Omega.cm to 5.3 x 10(-4) Omega.cm, and the effective total transmittance improves slightly in the near-infrared region. The efficiency of HJT solar cells with ITO films deposited at high H2O partial pressure is lower due to the deterioration of fill factor (FF), even though the short circuit current (Isc) increased. Thus, the maximum HJT solar cell efficiency of 25.30% is achieved at low H2O partial pressure. In addition, the perfor-mance of HJT solar cells under a nitrogen environment without illumination was tracked. It is observed that the high cell efficiency obtained with low H2O partial pressure has a larger degradation, which is mainly derived from the FF degradation.

提升晶硅异质结(HJT)太阳电池的电流有望进一步提高电池效率,透明导电氧化物薄膜(TCO)是影响HJT太阳电池电流的重要功能层.该文首先介绍了TCO薄膜的自身特性,包括掺杂元素和掺杂比例、制备技术对薄膜特性的影响.同时总结了薄膜特性对HJT太阳电池性能的影响.最后阐述了TCO薄膜应用的最新进展及发展趋势,增加盖帽层或多层TCO薄膜有望改善薄膜整体特性及电池性能.以期指导TCO薄膜特性的优化,从而进一步提高HJT太阳电池效率,加快HJT太阳电池产业化进程.

Tin-doped indium oxide (ITO) thin films were prepared at low substrate temperature by direct-current magnetron sputtering technology and applicated as the electrode of silicon heterojunction solar cells (HJT). The chemical, electrical and optical properties of ITO films deposited at different sputtering power are investigated. The optimized ITO films are applied as electrode of HJT solar cells, and the conversion efficiency of more than 25.22% is obtained. In addition, the passivated degradation resulting from ITO deposition is analyzed. The result shows that the degradation is recovered by the annealing process. Finally, the degradation of solar cell efficiency in dark nitrogen environment is tracked. It is found that the solar cells with the highest average conversion efficiency have poor stability, which is mainly attributed to the degradation of the fill factor.

Glass frits, as a critical ingredient, plays an important role in silver paste and determine sintering properties of the silive paste and contact quality with silicon solar cells. Here glass frits with different contents of TeO 2 additive were prepared and used to investigate the sintering process of Ag paste on crystalline Si (c-Si) solar cells. Microstructure and electrical properties of the corresponding Ag grids and the resulted c-Si solar cell performance were characterized systematically. The results show that TeO 2 can improve the densification and conductive performance of the Ag grids. Moreover, TeO 2 can promote the growth of Ag nanocrystallites in the glass layer between the Ag grid and c-Si wafer, thus reduce the contact resistance of the Ag grid. However, excessive TeO 2 addtive has a negative influence on the conductivity of the Ag grid due to the increased thickness of the glass layer. Therefore, the content of TeO 2 should be compromised for the solar cell to realize high conversion efficiency.

Transparent conducting oxide films were performed from SnO2-doped In2O3 with different doping ratio of 97:3 and 95:5 (ITO) by pulsed DC magnetron sputtering in argon and oxygen atmosphere. The effect of oxygen content on the structural, electrical and optical properties of films was investigated. Proper oxygen content improved the properties of ITO films. All films showed the polycrystalline structures. The optimal Hall mobility and resistivity reached 32.2 cm(2)/V.S and 4.5 x 10(-4) Omega cm, respectively. The average transmittance in the 400-1100 nm wavelength range was above 88 %. The optimized ITO films with Lightly and heavily doped ratio are appropriately chosen as front and back electrode of silicon heterojunction solar cells respectively, and the conversion efficiency of more than 24 % were obtained.

As a typical kind of high‐efficiency crystalline silicon (c‐Si) solar cell, amorphous/crystalline silicon heterojunction (SHJ) solar cell is stepping into mass production currently. It is of great significance to recover Ag from unqualified, broken, and end‐of‐life (EoL) SHJ solar cells. Herein, a facile method including alkaline chemical immersion and pyrolysis is developed. By immersing the solar cell into a sodium hydroxide (NaOH) aqueous solution for a period of time, Ag electrodes can be peeled off effectively. The increase of the concentration (C s) and the temperature (T s) of the NaOH solution shortens the peeling‐off time (t p) of the electrodes. It is deduced that the heated alkaline environment can accelerate the ester hydrolysis of the cured resin at the contact interface between Ag electrode and transparent conductive oxide (TCO) layer, which weakens the bonding strength of the Ag electrode. After cleaning, drying, and milling, the peeled‐off Ag electrodes are pyrolyzed in the air at 500 °C for 60 min to remove the cured resin completely. As a result, Ag powder is obtained with high purity over 99% and almost without mass loss since it is not involved in any chemical reaction during the whole recovery process.

Glass frits, as a critical ingredient, plays an important role between Ag electrode and crystalline silicon (c-Si) solar cells and determines sintering properties of the silver paste and contact quality with c-Si solar cells. Here glass frits with different contents of TeO2 are prepared and used to investigate the sintering process and effects of contact quality of Ag pastes on c-Si solar cells. Microstructures and electrical properties of the Ag/Si contact interface and performances of the resultant c-Si solar cells are characterized systematically. The results show that TeO2 promotes the growth of Ag nanocrystallites in the glass layer between Ag grids and c-Si wafers, thus reduces the contact resistance of the Ag grids and improves the contact quality of the Ag/Si interfaces. Moreover, TeO2 improves the densification and conductive performances of the Ag grids. However, excessive TeO2 has a negative effect on the conductivity of the Ag grid due to the increased thickness of the glass layer. Based on the competing factors played by TeO2, the conversion efficiency is the highest at an optimized TeO2 content similar to 40%.

More and more crystalline silicon (c-Si) solar cells, which are dominating the photovoltaic (PV) application, will be decommissioned after the service term due to the performance degradation. It will be valuable if the degraded c-Si solar cells can be recycled for reuse. For this, to restore the performance of the recycled c-Si solar cell becomes important. Here, we developed a two-step Ag/Cu electroplating method to repair Ag grid electrodes of the degraded c-Si solar cell. Such repair improved aspect ratio and excellent conductivity of the repaired Ag/Cu finger electrodes were obtained. Meanwhile, the absolute efficiency value of the repaired c-Si solar cell had 118% improvement after the Ag/Cu plating repairing process. In addition, the two-step plating Ag/Cu process is easy to operate, economic and friendly to the environment. These results demonstrated that the two-step electroplating Ag/Cu could be a promising method to repair and reuse the degraded c-Si solar cells.

The needle-like antireflection Hf-doped In2O3 thin films (IHFO) were prepared at a substrate temperature of 200 degrees C by glancing angle radio frequency magnetron sputtering technology. The structural, electrical and optical properties of the needle-like IHFO thin films were characterized. The significant reduction of reflection loss of the conventional and needle-like IHFO bilayer films deposited on the textured silicon was observed. The short-circuit current and efficiency of the solar cell were improved by 0.52 mA/cm(2) and 0.39% utilizing a needle-like IHFO thin film as an antireflection layer.

Ti and H co-doped In2O3 transparent conductive polycrystalline films (ITHO) were grown at a low substrate temperature of 150 °C by radio frequency magnetron sputtering for the applications of silicon-based heterojunction or other thin film solar cell. The effect of H2 flow rate on the structure, electrical and optical properties of the films was investigated. We will further improve film properties and employ it as electrode of heterojunction solar cell in the future.

The additives ethyl cellulose and polyamide wax of positive Ag paste with different viscosities and rheological behaviors were studied to optimize the screen printing performance of the Ag paste, the morphology, densification and resistivity of Ag electrodes. The roles of ethyl cellulose and polyamide wax in the viscosity as well in theological behavior were different. Ethyl cellulose was mainly used to improve the viscosity of the Ag paste while polyamide wax was used to improve capability of shear-thinning of the Ag paste. Because screen-printing performance is mainly determined by rheological behavior, the ratio of ethyl cellulose over polyamide wax becomes thus critical. By comparing morphology, densification and resistivity of Ag electrodes, we find that the optimum ratio of ethyl cellulose over polyamide wax is 1:5 in our case. Besides, the screen-printing performance of the paste with this ratio is also optimized. The development of new Ag paste and the way of optimizing performance of the Ag paste reported in this paper are very beneficial to further improve the efficiency of current commercial silicon based solar cells.

Front side Ag pastes with different sub-micrometer silver particle contents for c-Si solar cells were prepared. The corresponding screen-printing performance, sintering behavior and electrical properties were investigated systematically. The results show that the Ag particle incorporation could improve the surface morphology and the densification of the Ag grids to achieve low resistivity. However, too much addition of the Ag particles may have a negative influence on the printing performance of Ag paste and result in a reduced aspect ratio of the Ag grids. Therefore, the content of Ag particles should be compromised for the solar cell to realize high conversion efficiency.

The relationship between processing conditions and specific chemical reactions led to film growth in plasma is identified by optical emission spectroscopy to simplify the optimization process of film properties. SiH⁎ transient behavior after plasma ignition in parallel plate silane/germane/hydrogen plasma is investigated with the variation of germane, hydrogen flow rate and power. The effect on interface property between p layer and intrinsic layer in amorphous silicon germanium solar cell is obtained. Hα⁎, Hβ⁎, SiH⁎ and GeH⁎ emission intensity is recorded when germane and silane/germane flow rate changes. Ge content is analyzed by optical band gap and Raman spectra of amorphous silicon germanium films. The results are expected to serve as a guide for improving the performance of solar cells.

TiO2表面亲疏水性对其催化、分离等应用至关重要.研究了600℃氢气氛退火处理对TiO2单晶表面亲疏水性的影响,并从表面结构和表面能两个方面探讨了其作用机制.润湿角随着氢分压的增加而增大.Raman光谱分析发现,氢化处理对TiO2体内晶体结构和成键结构的影响并不明显.而原子力显微镜(AFM)测试结果显示TiO2单晶的表面却发生了微结构的变化,粗糙度从原来的0.8增加至2.5nm左右.同时X射线光电子能谱仪(XPS)分析发现氢化处理的TiO2单晶表面的化学状态也发生了改变,部分Ti原子从+4价还原为+3价,随着氢化程度的增加,更多Ti原子的价态发生了上述转变.通过测量不同极性液体的润湿性发现氢化处理对TiO2表面的极性有显著影响,氢化处理可以使极性大的液体在TiO2表面的润湿角更小.通过氢化处理对TiO2材料的表面进行化学修饰可以实现对其亲疏水性的调控.

The environmental-friendly hematite iron oxide (α-Fe2O3) has important application prospects in the photocatalysis field owing to its narrow indirect band gap. Here, we report a band gap engineering of α-Fe2O3 by incorporation of electrochemically-generated atomic hydrogen at moderate conditions. The ultraviolet–visible spectra show the reduction of the α-Fe2O3 band gap after hydrogenation and the absorption region from 200–800 nm is enhanced, especially in the visible light region. First principles calculation reveals the mixing of the new hybrid energy level with the valence band top resulting in a decrease in the band gap of α-Fe2O3. Further photocatalytic degradation experiments of dyes demonstrate that the photocatalytic efficiency of α-Fe2O3 can be greatly enhanced by the atomic hydrogen incorporation. The hydrogenated α-Fe2O3 can be easily recycled by magnets and has good photocatalytic stability. These findings offer possibilities for utilizing this inexpensive and earth-abundant oxide materials in the pollution controlling areas.