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The origins of parasitic heating for photovoltaic (PV) technologies based on silicon, perovskites, and their combination in monolithic tandems are investigated. To quantify heating losses, the cooling score (CS) as a new simple metric, representing the percentage of incident solar irradiance not contributing to module heating is introduced. This is a function of both the optical structure and power conversion efficiency (PCE) of the PV modules and allows a fair comparison between different technologies under identical performance‐evaluation scenarios. Silicon single‐junction devices have the lowest CS due to their low bandgap (causing significant carrier thermalization losses) and their use of light‐trapping structures to increase their PCE which also undesirably increases parasitic absorption of sub‐bandgap photons. Conversely, perovskite single‐junction devices show the highest CS in all studied performance‐evaluation scenarios thanks to their wider bandgap and high absorption coefficient, enabling absorption of all solar photons that may contribute to the photocurrent without requiring light‐trapping structures. While perovskite/silicon tandems minimize thermalization losses, they also usually employ light‐trapping structures in their bottom cell to increase their PCE, which lowers their CS. Through simulation and outdoor experiments, it is demonstrated that an efficient module‐cooling environment may significantly suppress the detrimental effects associated with a low CS. [ABSTRACT FROM AUTHOR]

Image processing is a mainstream processing method. When people enjoy artists' singing videos, there will be a problem that the subtitles of the lyrics are out of sync with the singer's mouth shape. This problem needs to be solved using image processing technology, letting the computer realize lip-reading recognition function and correct the mouth shape and lyrics subtitles in the image according to the extracted lip-reading data, so that the mouth shape and lyrics in singing practice can be synchronized. Lip-reading information can effectively improve the accuracy of language cognition, save part of capital and manpower investment, and make viewers get a good audio-visual interactive experience. The results show the following: (1) After the UI test, the system user interface function design is reasonable and there is no bad BUG. We can find that the average processing time of each frame is 628 ms, the system performance evaluation is good, and the success rate can be as high as 98.80%. 0.36724 s is the average time for each step when the system processes the image. (2) The human image can basically identify the portrait area and lip area from various angles. (3) Compared with DCT and DWT, the recognition rate of the two cascade lip region feature extraction methods is improved by nearly 10%, and the feature vector dimension is reduced by nearly 65%. (4) Classify the mouth shape more finely and optimize the image of the tester's mouth shape to make the mouth shape closer to the standard mouth shape. (5) After systematic correction of mouth shape and subtitles, the success rate is higher than 90%. Finally, we can find that the running effect is good and the method has achieved high results, which can carry out the details of the next optimization work. [ABSTRACT FROM AUTHOR]

Perovskite single-junction devices show highest CS, followed by perovskite/silicon tandems. Cooling score, parasitic heating, perovskites, silicon, tandem Keywords: cooling score; parasitic heating; perovskites; silicon; tandem EN cooling score parasitic heating perovskites silicon tandem 1 1 1 06/27/23 20230623 NES 230623 B Cooling Score b In article number 2300013, Lujia Xu, Stefaan De Wolf, and co-workers introduce the cooling score (CS) to quantify parasitic heating for photovoltaic technologies. [Extracted from the article]

Perovskite solar cells (PSCs) have witnessed a meteoric rise in device performance. However, maintaining photostability, particularly under thermal stress, remains a challenge due to defect formation in the perovskite layer. This study introduces europium (III) trifluoromethanesulfonate [Eu(OTF)3] as a multifunctional additive in two‐step processed perovskite films, significantly improving the performance and high‐temperature photostability of n‐i‐p PSCs. Density function theory (DFT) calculations reveal that the OTF− anion strongly coordinates with Pb2+, effectively inhibiting iodine vacancy defect formation. The addition of Eu(OTF)3 promotes perovskite grain growth to ≈2 µm and enhances film crystallinity. PSCs with a structure of ITO/SnO2/perovskite/PDCBT/NiOx/Au achieve a champion power conversion efficiency (PCE) of 23.8%. Under 85 ± 5 °C and 1 sun illumination at an open circuit in ambient air, the PSCs with Eu(OTF)3 retain 82% of their initial PCE after aging for 1500 h. [ABSTRACT FROM AUTHOR]

Some N‐tosylhydrazone derivatives were effectively synthesized under solvent‐free conditions by using a grinding method at room temperature. The short reaction time, clean and mild process with simple workup and easy purification of the target compounds were salient features of the present protocol, which enables straightforward access to N‐tosylhydrazones. Among the tosylhydrazone derivatives evaluated, compound 3 l exhibits excellent apoptosis‐promoting and anticancer potential against triple‐negative breast cancer (TNBC) cell lines. This research shows that our synthesized compound 3 l may be a desirable and effective therapeutic drug against TNBC. Daily grind: Some N‐tosylhydrazone derivatives are effectively synthesized under solvent‐free conditions by using a grinding method. The short reaction time, clean and mild process with simple workup and easy purification of target compounds are salient features of the protocol, which enables straightforward access to N‐tosylhydrazones. Among the tosylhydrazone derivatives evaluated, one compound exhibits excellent apoptosis‐promoting and anticancer potential against triple‐negative breast cancer (TNBC) cell lines, indicating that our synthesized compound may be a desirable and effective therapeutic drug for TNBC. [ABSTRACT FROM AUTHOR]

In this work, tunnel SiO 2 /a-Si:H stacks are trialed as passivated contacts to laser doped p + and n + regions. The passivation performance and contact resistivity are investigated as a function of the tunnel SiO 2 thickness and annealing condition. We find that the SiO 2 /a-Si:H stack provides excellent passivation to laser doped n + regions, with corresponding low recombination current density ( J o ) values. A lower level of surface passivation is achieved by the SiO 2 /a-Si:H stack on laser doped p + regions. A post-deposition forming gas anneal (FGA) at 400 °C is found to improve the passivation performance to laser doped p + regions and deteriorate the passivation to laser doped n + regions. Acceptable contact resistivity ( ρ c ) values have been obtained for both laser doped n + and p + regions after aluminum metallization and a post FGA to activate the alloying process between the a-Si:H and aluminum layer. In the final part of this work implementation of the passivated contacts to laser doped regions into a simplified interdigitated back-contact (IBC) solar cell fabrication process is proposed. Simulation result suggests that IBC device with an efficiency of up to 23% can be achieved using the obtained experimental results. [ABSTRACT FROM AUTHOR]

We present an approach to characterize the relative saturation current density (Joe) and sheet resistance (RSH) of laser doped regions on silicon wafers based on rapid photoluminescence (PL) imaging. In the absence of surface passivation layers, the RSH of laser doped regions using a wide range of laser parameters is found to be inversely proportional to the PL intensity (IPL). We explain the underlying mechanism for this correlation, which reveals that, in principle, IPL is inversely proportional to Joe at any injection level. The validity of this relationship under a wide range of typical experimental conditions is confirmed by numerical simulations. This method allows the optimal laser parameters for achieving low RSH and Joe to be determined from a simple PL image. [ABSTRACT FROM AUTHOR]

This paper outlines the development of fully screen-printed, uniformly diffused, bifacial, n -type silicon solar cells produced using a lean processing sequence and industry-standard equipment. An average batch efficiency of 21.4% was measured at standard test conditions for an optimised bifacial cell batch (i.e. illumination on the front surface only). The results of open circuit voltage ( V OC ) and fill factor ( FF ) loss analyses are presented for select batches. By targeting reductions in the largest recombination components, optimised batch V OC was increased by 15 mV compared to the baseline case. The two largest recombination components limiting V OC in optimised devices are front contact recombination and passivated rear surface recombination. The largest FF loss components for optimised devices are the emitter sheet resistance and front contact resistance. [ABSTRACT FROM AUTHOR]

Parasitic absorption in transparent electrodes is one of the main roadblocks to enabling power conversion efficiencies (PCEs) for perovskite‐based tandem solar cells beyond 30%. To reduce such losses and maximize light coupling, the broadband transparency of such electrodes should be improved, especially at the front of the device. Here, the excellent properties of Zr‐doped indium oxide (IZRO) transparent electrodes for such applications, with improved near‐infrared (NIR) response, compared to conventional tin‐doped indium oxide (ITO) electrodes, are shown. Optimized IZRO films feature a very high electron mobility (up to ≈77 cm2 V−1 s−1), enabling highly infrared transparent films with a very low sheet resistance (≈18 Ω □−1 for annealed 100 nm films). For devices, this translates in a parasitic absorption of only ≈5% for IZRO within the solar spectrum (250–2500 nm range), to be compared with ≈10% for commercial ITO. Fundamentally, it is found that the high conductivity of annealed IZRO films is directly linked to promoted crystallinity of the indium oxide (In2O3) films due to Zr‐doping. Overall, on a four‐terminal perovskite/silicon tandem device level, an absolute 3.5 mA cm−2 short‐circuit current improvement in silicon bottom cells is obtained by replacing commercial ITO electrodes with IZRO, resulting in improving the PCE from 23.3% to 26.2%. [ABSTRACT FROM AUTHOR]