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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]

Over the past few years, perovskite solar cells have arisen as a technology to potentially side with mainstream silicon photovoltaics (PVs) to help drive the transition towards renewable sources of energy. The coupling of perovskites with silicon in a tandem configuration may accelerate this development due to the remarkably high power conversion efficiencies possible with such devices. However, most of the perovskite/silicon tandem achievements so far have been confined to the lab environment, with only a few reported tests under outdoor conditions, using packaged devices. Nevertheless, one of the major challenges for perovskite/silicon tandem technologies, in addition to scale‐up, lies in the cell‐to‐module (CTM) translation, which for the perovskite/silicon tandem concept is complicated by perovskite‐imposed constrains such as a low‐temperature resilience, imposing challenges regarding tabbing and lamination, as well as a high sensitivity to moisture ingress, mandating the search for adequate encapsulation materials and methods. Herein, these challenges are described and assessed in depth and a perspective on future directions toward module design, tailored for perovskite/silicon tandem PVs is given, combining high performance with excellent durability. The discussion also holds relevance for all‐perovskite and other emerging PV technologies seeking market entry. [ABSTRACT FROM AUTHOR]

High carrier recombination loss at the contact regions has become the dominant factor limiting the power conversion efficiency (PCE) of crystalline silicon (c‐Si) solar cells. Dopant‐free carrier‐selective contacts are being intensively developed to overcome this challenge. In this work, vanadium oxide (VOx) deposited by atomic layer deposition (ALD) is investigated and optimized as a potential hole‐selective contact for c‐Si solar cells. ALD VOx films are demonstrated to simultaneously offer a good surface passivation and an acceptable contact resistivity (ρc) on c‐Si, achieving a best contact recombination current density (J0) of ≈40 fA cm−2 and a minimum ρc of ≈95 mΩ.cm2. Combined with a high work function of 6.0 eV, ALD VOx films are proven to be an effective hole‐selective contact on c‐Si. By the implementation of hole‐selective VOx contact, the state‐of‐the‐art PCE of 21.6% on n‐type c‐Si solar cells with a high stability is demonstarted. These results demonstrate the high potential of ALD VOx as a stable hole‐transport layer for photovoltaic devices, with applications beyond c‐Si, such as perovskite and organic solar cells. [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]

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]

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]