Progress in Photovoltaics最新文献

Tunnel oxide passivated contact (TOPCon) solar cells are on their way to becoming the next leading cell concept in industrial solar cell manufacturing. However, the efficiency gain compared to state-of-the-art PERC cells comes at the cost of additional processes in the manufacturing route. Therefore, it is of utmost importance to increase the profitability of the TOPCon cell architecture by reducing the capital and operating costs as much as possible. In addition to the development of production machines with high throughput and small footprint, the main lever for wet chemical processes is to reduce the consumption of expensive chemicals while maintaining a high process quality. In this work, this goal is pursued with a focus on wet chemical edge isolation. This process is industrially mainly performed in a combination of an inline process for single-sided glass removal followed by a batch process for rear-side emitter removal (cluster process). This paper presents our approach to reduce the inline process time without increasing the HF concentration. Furthermore, the rear surface morphology after the alkaline etching at different KOH concentrations with and without a new generation of polishing additive is characterized, and the effect on the implied open-circuit voltages is shown. The influence of dissolved potassium silicate is also investigated in order to increase the lifetime of the KOH bath. Based on the results, we present TOPCon cell results with efficiencies of about 23.5%, as well as cost of ownership calculations for the most promising approaches and discuss cost of ownership calculations for a US manufacturing scenario.

Solar cells fabricated from short-carrier lifetime materials face efficiency limitations because of high recombination rates, particularly within the depletion region. Kesterite solar cells offer a promising alternative to conventional solar cells but suffer from short-carrier lifetimes. This work introduces a comprehensive analytical model applicable to such solar cells. We developed a novel approach to accurately represent the recombination rates of the carriers within the depletion region using a Gaussian function. This model overcomes the limitations of existing approximations and enables more precise dark current calculations. Additionally, we employed a fully analytical generation rate calculation based on the transfer matrix method for accurate photocurrent determination. The effectiveness of this model was validated by comparing its results with simulated and experimental data for kesterite solar cells, demonstrating excellent agreement in dark current and photocurrent, with maximum percentage errors of 1.9% and 1.7%, respectively. Beyond accuracy, the model also achieved a 75-fold improvement in computation speed compared to finite element method simulations. This highlights the effectiveness of the model in capturing the complex recombination processes within kesterite solar cells and in providing a valuable tool for understanding and optimizing the performance of solar cells based on short-lifetime materials, particularly kesterite-based devices with one-sided junction characteristics.

Self-assembled molecules (SAMs) have emerged as highly promising materials for interface engineering in perovskite solar cells, yet significant challenges remain in terms of the mechanisms of interfacial interactions within the devices. In this study, we synthesized BrPA-CPA by introducing two bromine atoms at the electron-donating end of the SAM molecule TPA-CPA. As an additive for printable mesoscopic perovskite solar cells (p-MPSCs), this modification, while reducing the surface electrostatic potential of the electron acceptor and weakening its interaction with Pb²⁺ defects, unexpectedly enhanced the passivation effect due to the introduction of multiple passivation sites, a true “blessing in disguise.” In addition to this, BrPA-CPA facilitates the oriented growth of perovskite crystals, minimizing defect formation and significantly suppressing non-radiative recombination. The band bending at the interfaces between the perovskite and electron transport layer/carbon electrode promotes efficient charge transport across the interfaces. As a result, the power conversion efficiency (PCE) of p-MPSCs increases from 16.01% to 17.17%. This work presents a novel, highly effective strategy for the design of SAM additives, leveraging the control of active sites and surface electrostatic potential, thereby offering a new pathway for optimizing perovskite solar cell performance.

Obtaining high-quality repeatability data is the basis for improving measurement precision. Due to the inherent instantaneous fluctuation nature of field test conditions, obtaining high quality repeatability measurement results of photovoltaic (PV) modules in the field is still challenging. In this paper, firstly, we defined repeatability of PV modules measurement in the field, including repeatability and relative repeatability of measured and standard test conditions (STC)-corrected electrical parameters for fielded PV modules. Because STC is quite difficult to directly obtain outdoors, the correction procedure 4 in IEC 60891:2021 is used to obtain module STC characteristics. Then, the effect of the correction procedure on repeatability of electrical parameters of PV modules in the field was studied. The results show that repeatability of electrical parameters is changed before and after correction process. The variation reason was revealed by the established repeatability error propagation model. It is remarkable that there exist module maximum power point offsets before and after module characteristics correction. Moreover, the covariance terms contribute significantly to repeatability variation for fielded PV modules. Finally, the effect of field test conditions variation on repeatability of electrical parameters of PV modules was studied. The relative repeatability precision of module STC maximum power between field and indoor measurements was also compared. It is found that there is a greater probability to obtain indoor-level repeatability results within 0.7–1.0 kW/m² irradiance ranges (3.29%–5.04%) than that within 0.3–0.7 kW/m² irradiance ranges (0.47%–2.90%) for PV measurements in the field. The obtained results in this paper can provide new insights into precise performance measurement of PV modules under dynamic outdoor environmental conditions.

The purpose of this study was to investigate the long-term reliability of various photovoltaic technologies in Japan under humid subtropical climatic conditions. The five investigated technologies were p-type aluminum back surface field (Al-BSF) single-crystalline silicon (p-type Al-BSF sc-Si), p-type Al-BSF multi-crystalline silicon (p-type Al-BSF mc-Si), copper indium gallium (di)selenide (CIGS), hydrogenated amorphous silicon (a-Si:H), and a-Si:H and hydrogenated microcrystalline silicon tandem (a-Si:H/μc-Si:H) photovoltaic modules. The monthly performance ratio (PR) was calculated based on the power outputs of the photovoltaic arrays and global solar irradiance in the same plane as the photovoltaic arrays, which were measured at 10-min intervals over 12 years. The PR was corrected to 25°C (PR_T=25) as defined by the standard test conditions. Furthermore, the power outputs of all the photovoltaic modules were measured by a pulsed solar simulator (indoor flash testing) from 2012 to 2019. The PR and PR_T=25 values showed that the annual degradation rates of the p-type Al-BSF sc-Si, p-type Al-BSF mc-Si, CIGS, a-Si:H/μc-Si:H, and a-Si:H photovoltaic modules were approximately 0.0%/year, 0.2%/year, 1.1%/year, 0.6%/year, and 1.2%/year, respectively, which were consistent with the results of the indoor flash testing. These results indicate that p-type Al-BSF sc-Si and mc-Si photovoltaic modules can show little annual degradation and should retain high, stable power generation performance for over 20 years. In contrast, the higher annual degradation rates of the investigated thin-film photovoltaic technologies suggest that they did not maintain performance of over 90% of the nominal power outputs even for 12 years.