Search

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]

High coverage film could be obtained from precursor film PEDOT: PSS-based inverted perovskite solar cell, via decreasing the amount of residual DMSO or mediating the evaporation rate of DMSO with continuous gradient annealing (GA) process at 65°C–85°C (heating rate of 20°C/5 min). • A remanent solvent management strategy was employed to prepare uniform film. • The influence of residual DMSO on the properties of the MAPbI 3 film was investigated. • High device reproducibility was obtained with gradient thermal annealing. Perovskite solar cells (PSCs) have been attracting tremendous attention due to ease of processing, flexibility, and high performance. Dimethyl sulfoxide (DMSO) and N, N-dimethylformamide (DMF) are the two most widely used solvents to dissolve perovskite precursors. Here, we investigate the impact of residual amount and evaporation rate of the DMSO inside the precursor films on the microstructure of the ultimate perovskite films. We decouple the DMSO and DMF solvents and demonstrate that DMSO component exhibits great and dominant influence on the final film morphology by using quasi in-situ photoluminescence (PL) measurement and X-ray diffraction (XRD) characterization of the wet films after spin-coating. Much more smooth and uniform perovskite films are obtained by careful management of remanent solvent, including decreasing residual amount by shelving the precursor films prior to heating and retarding the evaporation of the solvent via adopting a gradient annealing (GA) process. In consequence, the as-prepared PEDOT: PSS-based inverted PSCs yield a champion efficiency of 15.59% with high reproducibility. This work shows great potential in preparing high-quality perovskite films through a simple remanent solvent management engineering. [ABSTRACT FROM AUTHOR]

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]