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In recent years, organic–inorganic hybrid perovskite (PVK) devices have attracted widespread attention with their high absorption coefficient and low-cost fabrication process. Formamidinium lead iodide (FAPbI3) perovskite solar cells (PSCs) have been reported to obtain high power conversion efficiencies (PCEs) due to the narrow bandgap. Zinc oxide (ZnO) has better electrical conductivity and high transmittance than tin (IV) dioxide (SnO2). However, the deprotonation behavior of ZnO limits its use in formamidinium (FA) or methylammonium (MA) devices, so it is mostly used in all-inorganic PSCs. In this work, to avoid the deprotonation behavior of ZnO, we prepared FAPbI3 PSCs using ZnO/SnO2 as bilayer electron transporting layers (ETLs), which improved the conductivity of the ETLs and promoted electron extraction and transfer. In addition, the decrease in the oxygen vacancy (Ov) on the bilayer ETLs contributed to the suppression of the non-radiative recombination of the device, thus enabling the achievement of a higher fill factor. As a result, the modified ETLs increased the PCE of FAPbI3 PSCs from 20.24% to 21.42% and improved the stability of the devices. The PCE of unpackaged devices increased steadily to 21.91% when stored in an N2 atmosphere for 183 days. [ABSTRACT FROM AUTHOR]

Semitransparent perovskite solar cells (ST‐PSCs) are highly promising for application in building‐integrating photovoltaics (BIPVs) due to their potential in tunable transparency and color. However, the comprehensive performance of ST‐PSCs falls quite short of the ideal requirements for BIPV. Herein, more attention is to review how to balance transparency and power conversion efficiency for ST‐PSCs. Optimizing transparent electrodes and the active layers are interesting strategies to achieve the transparency required by devices. In addition, to obtain color ST‐PSCs, tuning the bandgap of perovskite layers and designing the optical structure of the electrode are effective strategies. Last but not least, three significant optical evaluation indexes of ST‐PSCs are described in the supporting information: average visible transmittance, color rendering index, and light utilization efficiency. [ABSTRACT FROM AUTHOR]

In order to fabricate nickel oxide (NiOX)-based perovskite solar cells with high efficiency and stability, adverse reaction and lattice mismatch are two urgent problems to be overcome. In this respect, interface engineering was carried out by multi-layer passivation NiOX HTLs (NiOX/2PACz/Poly-TPD/PEAI) to provide optimized interface contact between NiOX and perovskite, ameliorate band alignment, and saturate the defect states. Application of 2PACz avoids direct contact of the hydroxyl groups (which causes degeneration of a device), improves conductivity, and reduces interfacial defects. The poly-TPD modification can provide an appropriate band alignment at the interface of NiOX/perovskite. PEAI was used to modify the Poly-TPD surface, and its −NH3 group can passivate unbonded Pb ions of perovskite. Thus, compared with previously reported single-function passivation materials, the multilayer passivation proposed in this paper integrates multiple functions. As a result, the NiOX/2PACz/Poly-TPD/PEAI-based wide bandgap PSCs obtain a champion power conversion efficiency (PCE) of 20.21% and maintain over 95% of their initial PCE values after storage in a nitrogen atmosphere for 1000 h. This finding provides a practical approach for fabricating high-performance regular PSCs with NiOX-based HTLs and supports their commercialization. [ABSTRACT FROM AUTHOR]

Although perovskite solar cells (PSCs) based on SnO2 have reached a power conversion efficiency (PCE) over 25%, large-scale fabrication remains the main obstacle to the commercialization of PSCs. Therefore, considering the process compatibility, low-temperature processing and large-area fabrication technologies have received widespread attention as those are ideal for upscaling of single and tandem devices. Herein, we demonstrated an effective atomic layer deposition (ALD) process by using H2O2 as an oxygen source and the deposition temperatures can be lowered up to 50 °C due to the high activity of H2O2. The low temperature deposition enables conformal coverage of the substrate and results in a pinhole-free film with high optical transmittance, excellent electron extraction properties, and large area uniformity. Notably, a high PCE of 20.70% is achieved for single junction PSCs based on ALD-SnO2 (50 °C). When the ALD-SnO2 applied to p-i-n structure perovskite/silicon heterojunction tandem solar cell, an efficiency of 26.67% was obtained. The results demonstrate the potential of the low-temperature ALD processed metal oxide for large-scale manufacturing of optoelectronic devices with competitive performances. [ABSTRACT FROM AUTHOR]

Flexible perovskite solar cells (FPSCs) with high efficiency and excellent mechanical flexible properties have attracted enormous interest as a promising photovoltaic technology in recent years. However, the performance or stability of FPSCs is still far inferior to that of conventional glass‐based perovskite solar cells (PSCs). Herein, a cross‐linking agent called aluminum acetylacetonate (Al(acac)3) is introduced as an interface layer between electron transport layer and perovskite absorber. Due to the well‐matched energy levels and improved grain size and crystallinity of the perovskite, a champion device with the highest power conversion efficiency (PCE) of 20.87% is achieved on the FPSCs. The device retains about 80% of its initial performance after 1000 h under >50% relative humidity without encapsulation. In addition, attributed to the Al(acac)3 super bending resistance, more than 91% of the original PCE is retained after 1500 bending cycles. This work proposes the substrate side optimization for improving device efficiency and stability which may provide a novel concept for promoting the development of FPSCs. [ABSTRACT FROM AUTHOR]

Abstract: The BaCo0.7Fe0.3− y Nb y O3− δ oxides (BCFNy, y =0.00–0.12) were synthesized by the conventional solid state reaction process and investigated as a novel cathode for intermediate temperature solid oxide fuel cells(IT-SOFCs). Cubic perovskite, with enhanced phase stability at higher Nb concentration, was obtained at y ⩾0.04. The unit cell volumes increased with y, reached a maximum at y =0.10, and then decreased. The niobium doping concentration also had a significant effect on the electrochemical performance of BCFNy materials. Among the various BCFNy oxides tested, BCFN0.10 possessed the smallest interfacial polarization resistance (R p). The R p was as low as 0.9406, 0.1300, 0.0211, and 0.0082Ωcm2 at 500, 600, 700, and 800°C, respectively. With a 220μm-thick Sm0.2Ce0.1O1.9 (SDC) as electrolyte and BCFN0.10 as the cathode, a fuel cell provides maximum power densities of 202, 350, 569, 820, and 1006mWcm−2 at 600, 650, 700, 750, and 800°C, respectively. The encouraging results suggested that BCFN0.10 was a very promising cathode material for IT-SOFCs. [Copyright &y& Elsevier]

Abstract: PrBaCo2O5+δ (PBCO) powder was prepared by a combined EDTA and citrate complexing method. The electrochemical performance of PBCO as a cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs) was evaluated. A porous layer of PBCO was deposited on a 42μm thick electrolyte consisting of Ce0.8Sm0.2O1.9 (SDC), prepared by a dry-pressing process. A fuel cell with a structure PBCO/SDC/Ni-SDC provides a maximum power density of 866, 583, 313 and 115mWcm−2 at 650, 600, 550 and 500°C, respectively, using hydrogen as the fuel and stationary air as the oxidant. The total resistance of the cell was about 0.41, 0.51, 0.57 and 0.77Ωcm2, respectively. This encouraging data identifies PBCO as a potential cathode material for IT-SOFCs. [Copyright &y& Elsevier]

Abstract: The Pr0.7Sr0.3Co1− y Cu y O3− δ (y =0.05–0.4) were synthesized by a sol–gel method. Crystal structure, electrical conductivity and electrochemical performance of these samples as cathode material for IT-SOFCs have been investigated. X-ray diffraction indicated that the samples with y ≤0.2 were single phase orthorhombic perovskite structure, but in the case of y ≥0.3, traces of a second phase were observed. The electrical conductivity decreased gradually with increasing Cu addition. Compared with Pr0.7Sr0.3CoO3− δ , all prepared Pr0.7Sr0.3Co1− y Cu y O3− δ compositions with y =0.05–0.3 show lower overpotential and the sample with y =0.1 exhibits the lowest overpotential. With Pr0.7Sr0.3Co0.9Cu0.1O3− δ cathode and porous NiO/Ce0.8Sm0.2O1.9 anode, the single cell based on SDC electrolyte was obtained by a dry pressing process. Maximum power density of the cell was 481 mW cm−2 at 750 °C. [Copyright &y& Elsevier]

Highlights • BaCo 0.7 Nb 0.2 Ta 0.1 O 3−δ (BCNT) cathode were prepared was prepared by solid phase reaction method. • The stability evaluation of the cathode showed the BCNT had sufficient stability during the operation. • Maximum power density of SDC electrolyte-supported cell reaches 626.41 mW·cm−2 at 800 °C. Abstract The BaCo 0.7 Nb 0.2 Ta 0.1 O 3−δ (BCNT) perovskite-type oxide was prepared by the conventional solid phase reaction method as a potential electrocatalyst for the oxygen reduction reaction. Its electrochemical properties were characterized. The results indicated that the BCNT oxide sintered at 1100 °C for 10 h had formed a single-phase cubic perovskite structure. And the BCNT–Sm 0.2 Ce 0.8 O 1.9 (SDC) mixture co-sintered at the same conditions showed good chemical compatibility and stability between BCNT and SDC. The BCNT cathode sintered at 1000 °C for 4 h on SDC electrolyte exhibited the lowest the polarization resistance (about 0.0495 Ω·cm2 at 800 °C). Moreover, with a 351 μm-thick SDC as electrolyte and BCNT as the cathode, maximum power densities of the single cell reached 466.81 and 626.41 mW·cm−2 at 750 and 800 °C, respectively, and the corresponding total interface polarization resistance of the cell were 0.0913 Ω·cm2 and 0.0552 Ω·cm2. Short-term stability of the cell showed that the cell was quite stable at 750 °C for 15 h. This suggested that BCNT was a very promising cathode material for IT-SOFCs. [ABSTRACT FROM AUTHOR]