The performance of BiVO photoanodes, especially under front-side illumination, is limited by the modest charge transport properties of BiVO. Core/shell nanostructures consisting of BiVO coated onto a conductive scaffold are a promising route to improving the performance of BiVO-based photoanodes. Here, we investigate photoanodes composed of thin and uniform layers of BiVO particles coated onto Sb-doped SnO (Sb:SnO) nanotube arrays that were synthesized using a sacrificial ZnO template with controllable length and packing density. We demonstrate a new record for the product of light absorption and charge separation efficiencies (η × η) of ∼57.3 and 58.5% under front- and back-side illumination, respectively, at 0.6 V. Moreover, both of these high η × η efficiencies are achieved without any extra treatment or intentional doping in BiVO These results indicate that integration of Sb:SnO nanotube cores with other successful strategies such as doping and hydrogen treatment can increase the performance of BiVO and related semiconductors closer to their theoretical potential.
N2,N2,N8,N8‐tetrakis(4‐(methylthio)phenyl)dibenzo[b,d]thiophene‐2,8‐diamine (DBTMT) is synthesized from three commercial monomers for application as a promising dopant‐free hole‐transport material (HTM) in perovskite solar cells (pero‐SCs). The intrinsic properties (optical properties and electronic energy levels) of DBTMT are investigated, proving that DBTMT is a suitable HTM for the planar p–i–n pero‐SCs. The champion power conversion efficiency (PCE) of the optimized pero‐SCs (with structure as ITO/pristine DBTMT/MAPbI3/C60/BCP/Ag) reaches 21.12% with a fill factor (FF) of 83.25%, which is among the highest PCEs and FFs reported for planar p–i–n pero‐SCs based on dopant‐free HTMs. The Fourier‐transform infrared spectroscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy spectra of MAPbI3 and DBTMT–MAPbI3 films demonstrate that there is an interaction between DBTMT and MAPbI3 at the interface through the sulfur atoms in DBTMT to passivate the defects, which is corresponding to the higher FF and PCE of the corresponding device.
Hexagonal boron nitride (h-BN) atomic layers were utilized as a passivation coating in this study. A large-area continuous h-BN thin film was grown on nickel foil using a chemical vapor deposition method and then transferred onto sputtered copper as a corrosion passivation coating. The corrosion passivation performance in a Na2SO4 solution of bare and coated copper was investigated by electrochemical methods including cyclic voltammetry (CV), Tafel polarization and electrochemical impedance spectroscopy (EIS). CV and Tafel analysis indicate that the h-BN coating could effectively suppress the anodic dissolution of copper. The EIS fitting result suggests that defects are the dominant leakage source on h-BN films, and improved anti-corrosion performances could be achieved by further passivating these defects.
For
the stability and commercial development of the perovskite
solar cells (PVK-SCs), synthesizing high-efficiency dopant-free hole-transport
materials (DF-HTMs) and exploring how the DF-HTM structure affects
the photovoltaic performance is inevitable. Two small-molecule DF-HTMs
based on 2,2′-bithiophene as a central part (denoted by BT-MTP
and DFBT-MTP) were designed and synthesized. DFBT-MTP, with two more
fluorine atoms substituted on the 2,2′-bithiophene group, exhibited
enhanced photovoltaic property as DF-HTMs, including larger backbone
planarity, declining highest occupied molecular orbit (HOMO) energy
level, increasing hole transportation, more effective passivation,
and efficient charge extraction. With fluorinated DFBT-MTP being applied
as DF-HTMs in p–i–n PVK-SCs, an efficiency of 20.2%
was achieved, showing ∼35% efficiency increase compared with
the nonfluorinated BT-MTP-based devices. The leading power conversion
efficiency (PCE) indicates that the fluorinated compounds should be
a promising direction for exploring high-performance DF-HTMs in the
p–i–n PVK-SCs.
Two-dimensional (2D) transition metal di-nitrides (TMN2) have been arousing great interest for their unique mechanic, electronic, optoelectronic, and magnetic properties. The recent successful growth of monolayer MSi2N4 (M = Mo...
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