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Perovskite solar cells (PSCs) have attracted extensive attention in the photovoltaic field, with their highest power conversion efficiency (PCE) reaching 26%. However, the commercialization of PSCs is severely hindered by the instability of precursor solutions and the narrow annealing window for perovskite films. Here, 2,3,5‐trichlorobenzaldehyde (3Cl‐BZH) is introduced into the organic salt precursor solution to eliminate excess organic amines through Schiff‐base reactions, avoiding subsequent irreversible amine‐cation reaction of formamidine‐methylammonium (FA‐MA+) and improve the stability of the precursor solution. Meanwhile, the chemical interaction between C═O group of 3Cl‐BZH and formamidinium (FA+) in the perovskite precursor contributes to the slow release of organic ions, which reduces the reaction rate between organic salt and PbI2, retarding the crystallization of perovskite film. The PSCs with a conventional annealing process achieve a champion efficiency of 24.08%, which derives from the defect passivation effect of 3Cl‐BZH. The PSCs with an ultrawide annealing window of 240 h for wet perovskite film in the air still maintain an efficiency of 22.01%. The aging‐resistant precursor and ultrawide annealing window are beneficial for reproducible, efficient, and low‐cost PSCs, which brings great prospects for the commercialization of PSCs. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) based on planar SnO2 (p‐SnO2) demonstrate excellent performance due to the superior properties of SnO2 as electron transporting layer (ETL). However, at present mesoporous SnO2 (m‐SnO2) still lags behind p‐SnO2 due to problems in the fabrication process of m‐SnO2. In this paper, a new strategy for preparing m‐SnO2 ETL is introduced which owns two valuable features: First, it applies a low temperature process to make mesoporous structure, which favors preserving the pristine properties of the raw SnO2 nanocrystals. Second, the degree of porosity and roughness of the m‐SnO2 layer can be well controlled, making it friendly to the following deposition process of PSCs. The performance of the PSCs based on the m‐SnO2 ETL prepared from this strategy shows an obvious improvement which is mainly from the improvement in Jsc and FF, suggesting a higher carrier collection efficiency for the m‐SnO2 ETL. The relevant characterizations including PL, TRPL, EIS, and KPFM confirm that the m‐SnO2 ETL possesses stronger electron extraction capability than the p‐SnO2 ETL. Hence, the proposed strategy can manifest the advantages of m‐SnO2 ETL meanwhile refrain its negative impacts, and thus promote the progress of the m‐SnO2 ETL‐based PSCs. [ABSTRACT FROM AUTHOR]

As-doped p-type ZnO films were grown on GaAs by sputtering and thermal diffusion process. Hall effect measurements showed that the as-grown films were of n-type conductivity and they were converted to p-type behavior after thermal annealing. Moreover, the hole concentration of As-doped p-type ZnO was very impressible to the oxygen ambient applied during the annealing process. In addition, the bonding state of As in the films was investigated by x-ray photoelectron spectroscopy. This study not only demonstrated an effective method for reliable and reproducible p-type ZnO fabrication but also helped to understand the doping mechanism of As-doped ZnO. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have attracted intense research interest in the last few years due to their excellent properties. However, the trap states at grain boundary (GBs) of perovskite films lead to charge recombination and perovskite film decomposition, which deteriorate the stability of PSCs. It has been demonstrated that the GBs passivation is an effective way to eliminate trap states and enhance the stability of PSCs. In this work, ethyl acetate (EA) and chlorobenzene (CB) were used as anti-solvent, mixing with phenyl-C61-butyric acid methyl ester (PC61BM) to replace pure antisolvent CB to control the GBs passivation of perovskite film. Meanwhile, enhanced interfacial hydrophobic characteristic effectively restricted the penetration of moisture. Correspondingly, with optimizing the volume ratio of EA/CB, the power conversion efficiency of PSCs based on CH3NH3PbI3 increased from 14.4 to 16.1% and the stability is greatly improved. This shows the adoption of a mixed solvent for EA and CB contained PC61BM as the solute can be used as an efficient tactic to passivate the surface crystal boundary, improve charge carrier transportation and device performance. [ABSTRACT FROM AUTHOR]

Remarkable progress has been achieved in organometallic halide perovskite solar cells (PSCs). However, poor environmental stability of PSCs has been proved to be challenging and needs further improvement. Here, a strategy of butylated hydroxytoluene (BHT) antioxidant additive with hydrophobic tert butyl and hydrophilic hydroxyl is developed to enhance the hydrophobicity, control nucleation rate and passivate the defect states of perovskite. The tert butyl group effectively prevents the penetration of moisture, as well as the formed hydrogen bond between hydroxyl group and iodine controls the assembly process of BHT and perovskite. By optimizing weight ratio of BHT and MAPbI3 in precursor solution, the power conversion efficiency of PSCs increased from 14.93% to 18.28% and greatly enhanced device stability compared with control device. We believe that our tactic of BHT additive can be applied to various perovskite films and will facilitate the realization of stable perovskite optoelectronics. In this work, BHT was added to the precursor. The main mechanism is proposed to be that the tert-butyls of BHT and the strong hydrogen bonds between hydroxyl and I atoms of MAPbI3 lead to the self-assembling behavior of BHT on the surface of perovskite layer, then forming lots of hydrophobic groups which work as a shield to resist the entry of water and oxygen. Hence, BHT can be fixed on perovskite surface to improve device stability. [ABSTRACT FROM AUTHOR]

Abstract: The growth of highly lattice-mismatched InAs0.3Sb0.7 films on (100) GaAs substrates by magnetron sputtering has been investigated and even epitaxial InAs0.3Sb0.7 films have been successfully obtained. A strong effect of the growth conditions on the film structure was observed, revealing that there was a growth mechanism transition from three-dimensional nucleation growth to epitaxial layer-by-layer growth mode when increasing the substrate temperature. A qualitative explanation for that transition was proposed and the critical conditions for the epitaxial layer-by-layer growth mode were also discussed. [Copyright &y& Elsevier]

Planar perovskite solar cells (PSCs) have been demonstrated as a promising architecture for efficient, large-scale, flexible and tandem solar cell. To date, unfortunately, most planar PSCs suffer from current-voltage hysteresis, which derives from interface mismatch, surface defects, ion migration, and ferroelectric property et al. Here, we demonstrate a facile strategy to significantly reduce the hysteresis and improve the performance of planar PSCs by doping gallium (Ga) into tin oxide (SnO 2) nanocrystal electron-transport layer using low-temperature solution‐processed method. It is revealed that the Ga-doped SnO 2 ETL owning better band alignment with the perovskite absorption layer, which is helpful for electron extraction. It is found that gallium doping severely decreases the trap state density in SnO 2 , leading to a lower recombination rate and negligible hysteresis. With the optimized doping concentration of Ga ions, the champion device achieves a highest PCE of 18.18% and the hysteresis index is reduced from 23.9% to 1.7%. Image 10894 • The Ga-doped SnO 2 is used as efficient electron transport layer in planar perovskite solar cells. • With gallium doping optimized, a maximum PCE of 18.18% and 1.7% hysteresis are achieved. • Optimized band alignment, decreased trap-state density and increased electron extraction are beneficial to less hysteresis. [ABSTRACT FROM AUTHOR]

There has been extensive investigation into phase orientation and phase distribution for improving charge transfer in 2D perovskites-based PSCs, but very few reports have focused on the enhancement of inter-phase charge transfer by passivation. In this work, a synergetic strategy is developed by introducing hydrochloric acid and [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) as additives to modulate phase distribution and passivate defects in (BA) 2 (FA) n−1 Pb n I 3n+1 (n = 9) quasi-2D perovskite films. In this process, perovskite films with suppressed phase segregation and PCBM molecules coated along the grain boundaries are obtained. PCBM is found to reduce the trap density by compensating defects, which accelerate inter-phase charge transfer and restrain nonradiative recombination, resulting in improved performance of quasi-2D PSCs. As a consequence, a high PCE of 15.01% with negligible hysteresis for quasi-2D PSCs is achieved. A synergetic strategy of phase distribution control and grain boundary passivation is developed for quasi-2D perovskite solar cells. The incorporation of PCBM into quasi-2D perovskite films with uniform phase distribution improves carrier lifetime and accelerates carrier extraction, resulting in an enhanced PCE. [Display omitted] • PCBM additive modifies the anti-solvent-assisted one-step process to fabricate the quasi-2D PSCs. • Inter-phase charge transfer is improved by the cooperation of optimised concentration of PCBM. • PCE is enhanced and hysteresis is eliminated for the devices with optimised PCBM incorporation. [ABSTRACT FROM AUTHOR]

Abstract: Sb-doped and undoped ZnO thin films were deposited on Si (100) substrates by radio frequency (RF) magnetron sputtering. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses revealed that all the films had polycrystalline wurtzite structure and c-axis preferred orientation. Room temperature Hall measurements showed that the as-grown films were n-type and conducting (ρ∼1–10Ωcm). Annealing in a nitrogen ambient at 400°C for 1h made both samples highly resistive (ρ>103 Ωcm). Increasing the annealing temperature up to 800°C, the resistivity of the undoped ZnO film decreased gradually, but it increased for the Sb-doped ZnO film. In the end, the Sb-doped ZnO film annealed at 800°C became semi-insulating with a resistivity of 104 Ωcm. In addition, the effects of annealing treatment and Sb-doping on the structural and electrical properties are discussed. [Copyright &y& Elsevier]

Combining two kinds of electron transport layer (ETL) which have complementary advantages into a bilayer structure to form a bilayer ETL is an effective way to transcend inherent limitations of single-layer ETL, which is very helpful in the development of perovskite solar cells (PSCs). In this work, a strategy is proposed to break constraints on the application of the staggered bilayer ETL in high-efficiency PSC, namely utilizing a built-in field to overcome the dilemma in E CBM making it possible to improve V OC and FF simultaneously by tuning the Fermi level of ETLs properly. According to the strategy, a bilayer ETL structure comprised of C-TiO 2 and SnO 2 layer and corresponding Li-doping process are developed, and the characterization results confirm the effectiveness of the strategy, making the potentials of the C-TiO 2 (Li)/SnO 2 bilayer ETL fully released for its application in high-efficiency PSCs: a V OC of 1.201 V for an ordinary triple-cation-perovskite-based PSC and a photoelectric conversion efficiency of 24.3% for a low-bandgap-perovskite-based PSC with high haze FTO superstrate are successfully achieved, indicating that the C-TiO 2 (Li)/SnO 2 bilayer ETL is a successful application paradigm of the proposed strategy and very promising in the application of high-efficiency PSCs., (© 2022 Wiley-VCH GmbH.)