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Inverted perovskite solar cells (PSCs) comprising formamidinium‐cesium (FA‐Cs) lead triiodide have garnered considerable attention due to their impressive efficiency and remarkable stability. Nevertheless, synthesizing high‐quality FA‐Cs alloyed perovskite films presents challenges, primarily attributable to the intricate interphase process involved and the absence of methylammonium (MA+) and mixed halogens. Here, the additive 3‐phosphonopropanoic acid (3‐PPA) is introduced, with bifunctional phosphonic acid groups, into the perovskite precursor to modulate the crystal growth and provide passivation at grain boundaries. In situ characterization reveals that the 3‐PPA can form a "rapid nucleation, slow growth" mechanism, resulting in perovskite films with enlarged grains and enhanced crystallinity. In addition, 3‐PPA serves to passivate grain boundary defects and release residual strain by forming molecular bridging, leading to the passivated films achieving a fluorescence lifetime of 5.79 microseconds with a favorable n‐type contact interface. As a result, the resulting devices incorporating 3‐PPA achieve a champion power conversion efficiency (PCE) of 24.05% and an ultra‐high fill factor (FF) of 84.22%. More importantly, the optimized devices exhibit satisfactory stability under various testing conditions. The findings underscore the pivotal role of multifunctional additives in crystallization control and defect passivation for high‐performance MA‐free and pure iodine PSCs. [ABSTRACT FROM AUTHOR]

Despite the enormous potential of all-inorganic perovskite solar cells due to their exceptional thermal stability in the field of photovoltaics, the performance of devices is still severely limited by interface defects. The electron transport layer (ETL)/perovskite interface plays a crucial role in the crystallization of perovskite film and the transport of charge carriers. However, perovskite film based on the solution method inevitably have a large number of defects at the interface. In this paper, a biocompatible potassium amino acid salt was introduced into carbon-Based all-Inorganic perovskite solar cells without hole transport layer (HTL). It can facilitate the formation of a smoother and more uniform interface between ETL and perovskite, thereby reduce the defect density. In addition, which can also rearrange the energy levels at the interface, improve the crystalline quality of the upper perovskite film, and suppress the hysteresis effect. Through the introduction of the functional material, the all-inorganic perovskite solar cell with high-efficiency and low-hysteresis was prepared. The optimzed device achieved the highest efficiency of 12.11%, which show 16.4% improvement when campared with the control samples. [ABSTRACT FROM AUTHOR]

The limited exciton lifetime (τ, generally <1 ns) leads to short exciton diffusion length (LD) of organic semiconductors, which is the bottleneck issue impeding the further improvement of power conversion efficiencies (PCEs) for organic solar cells (OSCs). However, efficient strategies to prolong intrinsic τ are rare and vague. Herein, we propose a facile method to efficiently reduce vibrational frequency of molecular skeleton and suppress exciton‐vibration coupling to decrease non‐radiative decay rate and thus prolong τ via deuterating nonfullerene acceptors. The τ remarkably increases from 0.90 ns (non‐deuterated L8‐BO) to 1.35 ns (deuterated L8‐BO‐D), which is the record for organic photovoltaic materials. Besides, the inhibited molecular vibration improves molecular planarity of L8‐BO‐D for enhanced exciton diffusion coefficient. Consequently, the LD increases from 7.9 nm (L8‐BO) to 10.7 nm (L8‐BO‐D). The prolonged LD of L8‐BO‐D enables PM6 : L8‐BO‐D‐based bulk heterojunction OSCs to acquire higher PCEs of 18.5 % with more efficient exciton dissociation and weaker charge carrier recombination than PM6 : L8‐BO‐based counterparts. Moreover, benefiting from the prolonged LD, D18/L8‐BO‐D‐based pseudo‐planar heterojunction OSCs achieve an impressive PCE of 19.3 %, which is among the highest values. This work provides an efficient strategy to increase the τ and thus LD of organic semiconductors, boosting PCEs of OSCs. [ABSTRACT FROM AUTHOR]

Silicon (Si) is a low‐cost, stable photovoltaic market contributor which is approaching its single‐junction theoretical efficiency limit. To further elevate the efficiency of crystalline Si (c‐Si) afterward, Si solar cells (SCs) need a proper top cell absorber in Si tandem SCs. Herein, the top cell absorber is studied by evaluating their current state of the art, the existing challenges, and possible future solutions which can enhance their efficiency. The progress of perovskite/Si tandem SC both for monolithic and four terminals is exceptional but still many challenges limit their commercialization. In view of these challenges, the relative's solutions are prescribed in detail to make possible their realization. III–V semiconductors being mature candidates still face a growth/fabrication problem, which makes them a costly option for III–V/Si tandem SCs. Effective growth strategies along with technical solutions are discussed in detail. Emerging chalcogenides are considered the future of tandem technology. Recent developments in the chalcogenides/Si tandem SC are highlighted and the possible options are presented. In the end, a short note is given on the near future tandem materials for Si tandem SCs. [ABSTRACT FROM AUTHOR]

Although the certified power conversion efficiency of organic-inorganic perovskite solar cells (PSCs) has reached 25.7%, their thermal and long-term stability is a major challenge due to volatile organic components. This problem has been a major obstacle to their large-scale commercialization. In the last few years, carbon-based all-inorganic perovskite solar cells (C−IPSCs) have exhibited high stability and low-cost advantages by adopting the all-inorganic component with cesium lead halide (CsPbI3−xBrx, x = 0 ~ 3) and eliminating the hole-transporting layer by using cheap carbon paste as the back electrode. So far, many astonishing developments have been achieved in the field of C−IPSCs. In particular, the unencapsulated CsPbBr3 C-IPSCs exhibit excellent stability over thousands of hours in an ambient environment. In addition, the power conversion efficiencies of CsPbI3 and CsPbI2Br C-IPSCs have exceeded 15%, which is close to that of commercial multicrystalline solar cells. Obtaining high-quality cesium lead halide-based perovskite films is the most important aspect in the preparation of high-performance C-IPSCs. In this review, the main challenges in the high-quality film fabrication process for high performance C-IPSCs are summarized and the film fabrication process strategies for CsPbBr3, CsPbIBr2, CsPbI2Br, and CsPbI3 are systematically discussed, respectively. In addition, the prospects for future film fabrication processes for C-IPSCs are proposed. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs), one of the most promising photovoltaic technologies, have been widely studied due to their high power conversion efficiency (PCE), low cost, and solution processability. The architecture of PSCs determines that high PCE and stability are highly dependent on each layer and the related interface, where nonradiative recombination occurs. Conventional synthetic chemical materials as modifiers have disadvantages of being toxic and costly. Natural molecules with advantages of low cost, biocompatibility, and being eco-friendly, and have improved PCE and stability by modifying both functional layers and interface. In this review, we discuss the roles of natural molecules on PSCs devices in terms of the perovskite active layer, interface, carrier transport layers (CTLs), and substrate. Finally, the summary and outlook for the future development of natural molecule-modified PSCs are also addressed. [ABSTRACT FROM AUTHOR]

Two polymerized naphthalimide derivatives, named as N‐TBHOB and N‐DBH, are prepared by quaternization. They exhibit excellent performance as electron‐transport layers (ETLs) in inverted organic solar cells (i‐OSCs). The results indicate N‐TBHOB with a reticulated structure owns a superior performance on electron extraction, electron transport, thickness tolerance, and less carrier recombination compared with N‐DBH with linear structure. The i‐OSCs based on N‐TBHOB with PTB7‐Th:PC71BM as the active layer achieve power conversion efficiencies (PCEs) of 10.72% and 10.03% under the thickness of 11 and 48 nm respectively, which indicates N‐TBHOB possesses better thickness tolerance than most of organic ETLs in i‐OSCs. N‐TBHOB also shows more competent performance than N‐DBH and ZnO in nonfullerene i‐OSCs for comprehensively improved Jsc, Voc, and fill factor (FF) values. Its i‐OSC with PM6:Y6 blend presents a high PCE of 16.78%. The study provides an efficient strategy to prepare ETLs by combining conjugated and nonconjugated units with a reticulated structure in the backbone for high‐performance i‐OSCs. [ABSTRACT FROM AUTHOR]

Hole transport layer‐free, carbon‐based, all‐inorganic CsPbI3 perovskite solar cells (PSCs) have exhibited great potential in photovoltaic applications owing to their low cost and excellent thermal stability. However, the low power conversion efficiency (PCE) hampers its development, mainly due to the existence of defects inside the CsPbI3 film or at TiO2 electron transport layer/CsPbI3 interface. Herein, these issues were addressed through a facile TiO2 post‐treatment strategy using 1‐butyl‐3‐methylimidazole hexafluorophosphate (BMIMPF6) ionic liquid. First, BMIMPF6 can passivate TiO2/CsPbI3 interface defects by forming strong bond between the electron‐rich N atoms and uncoordinated ions. Second, BMIMPF6‐modified TiO2 shows reduced hydrophilicity, inducing decreased heterogeneous nucleation and is favorable for obtaining high‐quality CsPbI3 film. Thirdly, the non‐volatile BMIMPF6 can diffuse to the perovskite film surface during annealing, further passivating defects located at perovskite grain boundaries and surface. Based on this one‐step ionic liquid interface‐to‐bulk modification, the modified device achieves a champion PCE of 15.09%, which is 14% higher than the control device (13.27%). In addition, the modified device also shows enhanced long‐term stability, which remains 96% of initial PCE after 30 days storage in dry air. The work demonstrates the superiority of multifunctional ionic liquid applied to all‐inorganic carbon‐based PSCs, providing a guidance for its commercialization. [ABSTRACT FROM AUTHOR]

The molecular design of a wide-bandgap polymer donor is critical to achieve high-performance organic photovoltaic devices. Herein, a new dibenzo-fused quinoxalineimide (BPQI) is successfully synthesized as an electron-deficient building block to construct donor–acceptor (D–A)-type polymers, namely P(BPQI-BDT) and P(BPQI-BDTT), using benzodithiophene and its derivative, which bears different side chains, as the copolymerization units. These two polymers are used as a donor, and the narrow bandgap (2,20-((2Z,20Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo [3,4-e]thieno[2,″30′:4′,50]thieno[20,30:4,5]pyrrolo[3,2g]thieno[20,30:4,5]thieno[3,2-b]indole-2,10 diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile) Y6 is used as an acceptor to fabricate bulk heterojunction polymer solar cell devices. Y6, as a non-fullerene receptor (NFA), has excellent electrochemical and optical properties, as well as a high efficiency of over 18%. The device, based on P(BPQI-BDTT):Y6, showed power conversion efficiencies (PCEs) of 6.31% with a JSC of 17.09 mA cm−2, an open-circuit voltage (VOC) of 0.82 V, and an FF of 44.78%. This study demonstrates that dibenzo-fused quinoxalineimide is a promising building block for developing wide-bandgap polymer donors. [ABSTRACT FROM AUTHOR]

The water pollution currently constitutes a severe threat to our living life, and MOF (metal–organic framework)-based photocatalysts offer an efficient route to clean various water pollutants in an eco-friendly manner. Integration of metal nanoparticles (MNPs) with photoactive MOFs has proven an effective way to further boost the photocatalytic performance. In this work, Ag/UiO-66-NH2 composites (UiO = University of Oslo) have been facilely assembled in two steps involving first wet impregnation of AgNO3 into UiO-66-NH2 followed by chemical reduction with NaBH4. Benefited from the built-in heterostructure that can promote both the electron–hole separation, and the absorption of the visible-light, Ag/UiO-66-NH2 composites exhibited an enhanced photocatalytic performance than the pristine UiO-66-NH2 towards photodegradation of RhB (Rhodamine B) dye under the irradiation of UV–Visible light. About 96% of RhB can be degraded by Ag/UiO-66-NH2 in a period of 40 min. Besides, Ag/UiO-66-NH2 demonstrated a good recycling stability which showed an only slight drop in the dye photodegradation efficiency after three consecutive runs. The current work suggests that Ag/UiO-66-NH2 composites have a great potential in practical application toward water remediation. [ABSTRACT FROM AUTHOR]

• The PPPF is proposed for radiative cooling of commercial silicon solar cells. • The PPPF has an average transmittance of >0.9 in the wavelength range of 0.3-1.1 µm. • The PPPF has an average emissivity of approximately 1 in the mid-infrared region. • The PPPF is suitable for passive cooling of curved surfaces, such as lasers and detectors. Radiative cooling is an electricity-free method for solar cells to dissipate waste heat, which has drawn much attention in recent years. In this paper, a periodic pyramid-textured polydimethylsiloxane (PDMS) film is proposed for radiative cooling of encapsulated commercial silicon solar cells. Spectral tests show that the proposed pyramid-textured PDMS film emits like a blackbody and simultaneously has an average transmittance of >0.9 in the silicon absorption spectrum from 0.3 µm to 1.1 µm. Outdoor cooling tests demonstrate that the encapsulated commercial silicon solar cells with the proposed textured PDMS film can be cooled by over 2 °C. Due to its good optical and flexible properties, the textured PDMS film has great potential for applications in the photovoltaic industry. [ABSTRACT FROM AUTHOR]

Growing concerns over non-renewable fossil fuel resources and anthropogenic emissions of greenhouse gases have attracted global interests towards development of sustainable and renewable energies using functional nanostructures. A sustainable approach that can confer multiple advantages is the engineering of nanostructures from the recycling of electronic waste (e-waste) materials. The present work reports a simplified, high-yield, and controllable strategy to prepare Cu-based heterojunction ultrathin films with a stratified morphology, in which the number, composition, and structure of two-dimensional (2D) Cu-based layers can be tailored. As electrodeposited, the bilayer Cu/Cu2O–Cu(OH)2 exhibited a pseudocapacitance behaviourwith high power density offering a promising potential for energy storage applications. A rapid post heat-treatment at a low temperature led to a partial transformation of Cu and Cu2O–Cu(OH)2 layers into CuO, resulting in the formation of a trilayer heterojunction ultrathin film with high energy harvesting performance as a photocathode for hydrogen production, in which the enhanced electron/hole separation and increased number of active sites across the interfacial regions resulted in photoelectrochemical current density as high as 2.6 mA cm−1 at −0.6 V vs. Ag/AgCl. To evaluate the environmental impacts associated with the valorisation process, a Life Cycle Assessment (LCA) containing four possible scenarios was comprehensively conducted. The LCA results highlighted (a) the critical requirement for sustainable and less-polluting chemical agents and substrates, and (b) the importance of such value-added recycling for the environment and the immense potential of e-waste applicability in developing advanced functional nanomaterials. [ABSTRACT FROM AUTHOR]

Recently, carbon-based perovskite solar cells have attracted wide attention in academia and industry because of their simple preparation process, low cost, and adaptability to roll-to-roll industrial production. The combination of ternary perovskite composition and carbon electrode configuration is expected to meet the requirements of device performance and stability. However, low grain size, and high density of grain boundary and surface defect states result in serious non-radiative recombination, which is one of the main gaps between the carbon-based perovskite solar cells and metal-electrode-based devices. Based on the consideration of crystal tuning and defect passivation of ternary CsFAMA thin films, the additive molecule 5-(Difluoromethoxy)-2-mercapto-1H-benzimidazole (DMB) with multifunctional groups were introduced into the film. XRD show that the (100) and (200) crystal plane orientation growth directed by the DMB additive lead to the formation of the micro-sized perovskite. XPS suggests that DMB not only modulates the crystallization of the films but also exists at the grain boundaries, and realizes the passivation of undercoordinated Pb2+ defects and inhibits the generation of Pb0. The defect state density is significantly reduced, and the carrier lifetime is greatly improved. The possible mechanism for perovskite crystal growth as well as defect passivation based on Lewis acid-base coordination and hydrogen bond was also proposed. After the introduction of DMB, a power conversion efficiency of 14.40% was achieved, which was 13.4% higher than that of the control device. After nearly 1200 h of environmental stability test, the DMB modified device still retained 95% of the original efficiency. This work emphasizes the feasibility of simultaneously realizing the crystallization modulation and defect passivation of carbon-based perovskite solar cells using the additive with multifunctional groups, and provides a reference for the commercialization of carbon-based perovskite solar cells. [Display omitted] • Commercially available carbon was used instead of the noble metals. • Crystallization modulation and defect passivation are realized simultaneously. • The C-PSC based on DMB additive show 13.4% increase in PCE. • The C-PSC based on DMB additive possess exceptional long-term stability. [ABSTRACT FROM AUTHOR]

Hole transporting layer (HTL)-free, carbon-based all-inorganic CsPbI 2 Br perovskite solar cells have attracted great attention with suitable band gap, excellent thermal stability, low manufacturing cost and simplified procedure processes. Focusing on issues including energy level match and contact between the carbon electrode and the perovskite layer that limit the device performance, passivation strategies are widely applied on the interfaces within perovskite solar cells. Herein, the effect of synergistic passivation of ethylammonium iodide (EAI) and phenethylammonium iodide (PEAI) on all-inorganic perovskite (CsPbI 2 Br) solar cells is studied for the first time. Results indicate that α-/δ-phase heterojunction and localized 2D/3D heterojunction formed on the CsPbI 2 Br film surface tend to reduce the trap density and promotes the energy level gradient arrangement. In addition, EA+ ions enter into the lattice and passivate the bulk phase defects of perovskite. As a result, the synergistic passivated devices (active area 0.0706 cm2) exhibit an increased PCE from 11.74% to 13.76% and a high fill factor (FF) of 80.32%, as well as promising long-term stability. [Display omitted] • The α-/δ-phase heterojunction and localized 2D/3D heterojunction were constructed by EAI and PEAI synergistic passivation. • The synergistic passivation reduces the trap density and promotes the energy level gradient arrangement. • It achieves a champion PCE 13.76% with a high FF of 80.32% based on HTL-free carbon-based CsPbI 2 Br PSCs. [ABSTRACT FROM AUTHOR]

Vertically aligned, free-standing crystallized TiO nanotube arrays with a length of 32 μm have been fabricated by a two-step anodization method. The TiO nanotube membrane can be detached from the Ti substrate through the secondary anodization process. The influence of the secondary anodization voltage on the morphology, crystalline phase and photovoltaic performance of the as-fabricated samples has been investigated. Results show that the side wall of TiO nanotubes becomes obviously thin as the secondary anodization voltage increases and leads to crack when the voltage reaches 25 V. The mass fraction of the anatase reduces by the increase of the voltage. Furthermore, the dye-sensitized solar cells (DSSCs) based on TiO nanotube arrays have been assembled. The energy conversion efficiency decreases with the increase of secondary anodization voltage, and a highest energy conversion efficiency of 10.6 % under UV illumination (368.1 nm) is obtained from the cell with TiO nanotube membrane re-anodizad at 15 V. [ABSTRACT FROM AUTHOR]

Because of its exceptional photoelectric qualities, exceptional stability, and plentiful element resources, the antimony selenide (Sb 2 Se 3) can be used as an absorber layer. The performance of solar cells needs to be further improved. Comprehending the various surface treatment conditions is instrumental in optimizing device performance. In this research, we pre-treated the fluorine-doped tin oxide (FTO) surface with ultraviolet ozone (UV/O 3) and investigated how the device (FTO/CdS (53 nm)/Sb 2 Se 3 (203 nm)/Spiro(120 nm)/Au(80 nm)) performance was affected by temperature of the substrate during the UV/O 3 treatment. It's interesting to note that the solar cells made with FTO after exposure to UV/O 3 have better interface quality and lower recombination losses, which significantly improves the Open circuit voltage (V OC) and Fill factor (FF). The result is an improvement in the device's Power Conversion Efficiency (PCE) from 7.13% to 8.14%. The work is aimed at developing an efficient strategy to improve the performance of Sb 2 Se 3 solar cells. [ABSTRACT FROM AUTHOR]

• A shape editing approach of single-DoF thick-panel deployable structures is proposed. • The mobility of thick-panel deployable structures is analyzed using screw theory. • The design of novel solar panels and space exposing platforms is further explored. Thick-panel deployable structures have great engineering prospects in aerospace large-scale structures. However, achieving any desired shape of the deployable structure without seams, compact folding, and single-degree-of-freedom (single-DoF) deployment is a significant challenge for aerospace engineering applications. In this study, we propose an approach to edit the shape of kirigami-inspired thick-panel structures that enable single-DoF flat deploying and compact folding. First, based on two-vertex six-crease kirigami-inspired TPUs, modular assembly of single-DoF thick-panel deployable structures are achieved. Second, the single-DoF characteristics of resulting thick-panel structures are verified using screw theory and topology. Third, panel cutting and merging of the assembled thick-panel structures is performed to ensure the topological closed-loop characteristics in the desired shape of the structures while maintaining its single-DoF characteristics. In addition, their potential engineering applications in space solar arrays and exposing platforms are further explored. The proposed method provides some references for the design of future thick-panel deployable structures. [ABSTRACT FROM AUTHOR]

We report the fabrication of intermediate-band solar cells (IBSCs) based on quantum dots (QDs), which consists of a standard P-I-N structure with multilayer stacks of InAs/GaAs QDs in the I-layer. Compared with conventional GaAs single-junction solar cells, the IBSCs based on InAs/GaAs QDs show a broader photo-response spectrum (> 1330 nm), a higher short-circle current (about 53% increase) and a stronger radiation hardness. The results have important applications for realizing high efficiency solar cells with stronger radiation hardness. [ABSTRACT FROM AUTHOR]

The organic-inorganic perovskite solar cells (PSCs) have recently attracted significant attention owing to their remarkable photovoltaic performance. Herein, we fabricate a novel perovskite absorber Cs 0.05 (FA 0.83 MA 0.17) 0.95 Pb 1−x Zn x (I 0.83 Br 0.17) 3 by using ZnBr 2 as an additive. The introduction of zinc increases the grain size and reduces the grain boundary defects. At the optimized concentration of 0.5 mol% ZnBr 2 additive, the x-ray diffraction (XRD) shows the perfect crystallization of the perovskite film. The enhanced crystallization of the perovskite structure suppresses the non-radiative recombination loss and prolongs the carrier lifetime. The optimized PSC presents a champion power conversion efficiency (PCE) of 15.64 % and shows a negligible hysteresis effect. Moreover, the increased built-in electric field (V bi) between the n-type Zn doped perovskite and the p-type CuSCN creates more driving force for the separation of photogenerated carriers and increases the open-circuit photovoltage (V oc) of the device. The unencapsulated device maintains more than 87 % of its original PCE after aging for 90 days in the ambient condition, while the control device can only maintain 60 % of its original PCE. These results suggest that the simple B-site ion-doped perovskite could be a good option for the future improvement of PSCs. [Display omitted] • A novel Cs 0.05 (FA 0.83 MA 0.17) 0.95 Pb 1−x Zn x (I 0.83 Br 0.17) 3 was fabricated by using ZnBr 2 additive. • The introduction of Zn promotes the perovskite crystallization and increases the grain size. • The optimized carbon-based PSCs obtained a PCE of 15.64 % with a negligible hysteresis. • Carbon-based Zn doped PSCs displays high air and thermal stability. [ABSTRACT FROM AUTHOR]

• Lead (Pb)-free perovskite Cs 2 SnI 6-n Br n can used as a top cell absorber for silicon heterojunction (SHJ) tandem solar cells. • Cs 2 SnI 5 Br/SHJ tandem solar cell with 39.1% PCE is achieved theoretically. • Highly stable and environment-friendly Cs 2 SnI 6-n Br n has the potential to replace toxic and unstable perovskites. Emerging Lead (Pb)-free perovskite solar cells are environment-friendly and show higher stability. Such materials are considered the future of the photovoltaic industry. However, the detailed understanding of these materials is still very limited experimentally as well as theoretically. In this work, all inorganic Pb-free perovskites Cs 2 SnI 6-n Br n have been studied as top cell materials for silicon heterojunction (SHJ)-based tandem solar cells. The optoelectronics characteristics including bandgap, optical absorption, effective masses and carrier mobility of Cs 2 SnI 6-n Br n have been calculated by the first-principle with varying Br- alloying. Details theoretical study show that the bandgap of Cs 2 SnI 6-n Br n can tuned over a range of 1.05 eV to 1.99 eV. In addition, carrier mobility has been modelled for the studied perovskites by deformation potential theory. Based on the calculated optoelectronics characteristics, a standalone Cs 2 SnI 6-n Br n solar cell is simulated and 20.5 % efficiency is reported. SHJ-based solar cell is used as the bottom cell with 28.5 % standalone efficiency under standard spectrum illuminations. Finally, the Cs 2 SnI 6-n Br n /SHJ tandem solar cell is designed and a simulated PCE of 39.1 % has been achieved with n = 1. The highest 1.46 V Voc is obtained with a 40.5 mA/cm2 matched current between the top and bottom cells. The proposed work gives a detailed study of Cs 2 SnI 6-n Br n perovskites and is expected to facilitate the production of Pb-free perovskites/SHJ tandem solar cells. [ABSTRACT FROM AUTHOR]

Abstract: Optical sensing of F−, Cl−, Br−, I−, OAc−, , , and by cis-dithiocyanatobis(2,2′-bipyridyl-4,4′-dicarboxylic acid)ruthenium(II) (N3) and bis(tetrabutylammonium) cis-dithiocyanatobis(2,2′-bipyridine-4-COOH,4′-COO−)ruthenium(II) (N719) have been investigated in dimethyl sulfoxide (DMSO), by means of UV–Vis absorption and emission spectrophotometric titrations. Additions of F−, OAc−, and in DMSO solution caused obvious UV–Vis spectral changes with appearance of several isosbestic points, and remarkable emission enhancements along with large blue shifts in emission bands. The values of F−-induced emission intensity enhancement factor (emission quantum yield enhancement factor), I/I 0 (φ/φ 0), were found to be 40 (86) and 38 (58) for N3 and N719, respectively. No obvious spectral changes were observed upon addition of Cl−, Br−, I−, and in DMSO solutions. Luminescent F− sensing in DMSO/H2O (4:1, v/v) has also been demonstrated to be operative with a luminescence enhancement factor of 12, indicating that N3 is very potential for practical application as fluorescent anion sensor in aqueous solution. An interaction mechanism of anion-induced deprotonation of N3 and N719 was confirmed, and the deprotonation reaction equilibrium constants of N3 and N719 were derived as well. [Copyright &y& Elsevier]

• A configuration of twofold spectrum split is proposed for high exergy efficiency in PV/T systems. • A coupling model of PV/T system is constructed and validated by our experiments. • Tailoring the spectral selectivity and deep temperature decoupling is enabled by our configuration. • Total energy and exergy efficiencies reach 0.829 and 0.276 for solar concentration of 30. Photovoltaic/thermal (PV/T) systems are improved from PV systems to harvest both electrical and thermal energy from the solar radiation, as well as cooling the PV cells. While the previous configurations with liquid-absorptive filters have partly solved the temperature coupling of PV cells and heat collector, the unsatisfactory spectral selectivity and inevitably interlayer heat transfer remain restrict the improvement of total exergy efficiency in PV/T systems. In this study, a twofold spectrum split configuration with both Therminol VP-1/Ag nanofluid and pure water is proposed. The complementary optical properties and free flow rate controls open a window to tailoring the spectral selectivity and deep temperature decoupling. A coupling model is constructed to describe the system, which is well validated by our simplified PV/T experiment and literature. Results show that the nanofluid absorbs the shorter unsuited radiation, and water captures the longer, leading to a high spectral match parameter (0.71) and low heat generation parameter (0.26) when for nanofluid thickness of 1 mm, water thickness of 10 mm and Ag nanoparticle volume fraction of 0.01 %. Total exergy efficiency increases with solar concentration, and the highest value of 0.276 is reached for solar concentration of 30 when flow rates of nanofluid and water are 0.032 and 0.029, with an accompanying total energy efficiency of 0.829. As a comparison, two previous PV/T systems have highest total exergy efficiencies even lower than 0.25. Temperature distributions revealed that the deep temperature decoupling in the proposed PV/T system enables a high-temperature heat collection during the low-temperature work of PV cells, which is responsible for the improvement. Our study points out an approach to combine the advantages of two liquid filters, to achieve both good spectral selectivity and deep temperature decoupling. [ABSTRACT FROM AUTHOR]

Ce-doped TiO 2 nanorod arrays as the mesoporous supporting layer and TiO 2 compacted electron blocking layer was simultaneously fabricated by one-pot hydrothermal method. Ce-doped TiO 2 nanorod was utilized as down-conversion luminescence centers and commercial available carbon was used in hole-transport-free perovskite solar cells. SEM indicated that the doping of Ce reduced the diameter of TiO 2 nanorods. XRD and EDS spectra demonstrate the successful incorporation of Ce ions. UV–Vis absorption spectra and PL emission spectra show that the down-conversion center Ce4+ can effectively utilize ultraviolet light and extend the absorption into the ultraviolet region. The carbon-based device using the optimized Ce doping concentration achieved power conversion efficiency (PCE) of 10.1%, which was 24.6% higher than that of undoped device. Ce doping changes the band gap of TiO 2 and the Fermi energy level, and thus improve the open circuit voltage. The open circuit voltage decay curve show that Ce-doped TiO 2 prolongs electron lifetime. EIS analysis hints that more carriers are generated. The UV stability has also been significantly improved., PCE of the optimized Ce-doped device still retains 90% of the initial value, however, the undoped device decreases to 55% of the initial value under light irradiation at ambient atmosphere for 12 h. • Ce dopnant change TiO 2 fermi energy level and improve the open circuit voltage. • Ce-doped device get 24.6% increase in conversion efficiency. • PCE of Ce-doped device retains 90% of the initial value. [ABSTRACT FROM AUTHOR]

In this study, a Yb3+, Er3+ co-doped TiO 2 inverted pyramid nanorod (NR) array and a compact TiO 2 film are simultaneously fabricated as the mesoporous support layer and electron-blocking layer, respectively, by a one-pot hydrothermal method. The scanning electron microscopy results show that the incorporation of Er3+ and Yb3+ causes changes not only in the growth rate of the NRs, but also in the TiO 2 NR morphology. The Er3+, Yb3+ co-doped TiO 2 NRs exhibit an inverted pyramidal morphology, which is beneficial for perovskite permeation and light utilization. Notably, the Er3+, Yb3+ co-doping causes changes in the band gap of TiO 2 and leads to 25% increase in the current density. The electrochemical impedance spectroscopy results show that the device based on the doped TiO 2 NRs has a higher recombination resistance and a lower transfer resistance than those of the undoped device, and thereby, the doped device exhibits a lower electron recombination rate. In addition, the upconversion Er and Yb co-doped device exhibits 25% higher current density and 17% higher photon-to-electron conversion efficiency, as revealed by the J-V test results. Moreover, the optimized efficiency of the TiO 2 NR array-based perovskite solar cell is determined to be 10.02%. Furthermore, the Er and Yb co-doped device exhibits a near-infrared response, an efficiency of 0.1% is achieved under infrared light (800–1100 nm) irradiation. This upconversion material can widen the photovoltaic responses of solar cells into the near-infrared region and improve the utilization of sunlight. Inverted pyramid TiO 2 : Yb3+, Er3+ nanorod array and the compacted electron blocking layer were simultaneously fabricate by one-pot hydrothermal method. The characterization results show that doped of Yb3+, Er3+ influenced the morphology of NRs and changed the band gap of TiO 2. Furthermore, the perovskite solar cell based on upconversion Er and Y co-doped TiO 2 device get 25% increase in current density and lead to 17% increase in photon-to-electron conversion efficiency. J-V test proves TiO 2 : Yb3+, Er3+ NRs had a response in near-infrared light and a PCE of 0.1% was achieved in 800–1100 nm. The impedance spectrum shows that the cell based on Yb3+, Er3+ doped has lower transfer resistance and higher recombination resistance. Image 1 • Inverted pyramid TiO 2 : Yb3+, Er3+ nanorod array and the compacted electron blocking layer was simultaneously fabricated. • Yb3+, Er3+ dopant changed the morphology and the band gap of TiO 2 NRs. • The co-doped device get 25% increase in current density and 17% increase in conversion efficiency. • The co-doped device had near-infrared response and a PCE of 0.1% was achieved in 800–1100 nm. [ABSTRACT FROM AUTHOR]

Abstract Sb 2 (S,Se) 3 are considered as a promising absorber material for solar cells owing to its earth-abundant, nontoxic constituent, simple phase and long-term durability. In this work, a facile chemical bath deposition followed by post-selenization was introduced to prepare Sb 2 (S,Se) 3 thin film, which leads to a graded band gap structure. The sulfoselenide Sb 2 (S,Se) 3 thin films with smooth morphology were obtained through optimizing the selenization process. Meanwhile, a low cost and substitutable carbon electrode was used as hole selection material. Sequentially, the full-inorganic Sb 2 (S,Se) 3 device with efficiency of 2.64% was also fabricated according to structure of FTO/CdS/Sb 2 (S,Se) 3 /Carbon, which is the highest value in CBD processed FTO/CdS/Sb 2 (S, Se) 3 /Carbon solar cells. Graphical abstract Image 1 Highlights • Full in-organic Sb 2 (S,Se) 3 device is fabricated by CBD route followed post-selenization. • A gradient band gap in Sb 2 (S,Se) 3 device is formed and exhibits efficiency of 2.64% with Voc of 645mV. • The development of the crystal structure and morphology with increasing temperature was investigated carefully. • The characteristics of the Sb2(S,Se)3 device were fully investigated. [ABSTRACT FROM AUTHOR]