Haibing Xie

TL;DR: A consensus between researchers in the field is reported on procedures for testing perovskite solar cell stability, which are based on the International Summit on Organic Photovoltaic Stability (ISOS) protocols, and additional procedures to account for properties specific to PSCs are proposed.

TL;DR: In this paper, a large improvement of Cu2ZnSnSe4 solar cell efficiency is presented based on the introduction of a Ge superficial nanolayer, which is explained by three complementary effects: the formation of a liquid Ge-related phase, the possible reduction of Sn multicharge states, and formation of GeOx nanoinclusions.

TL;DR: In this article, a hierarchical ITO/Fe2O3/FeTiO5/FeNiOOH multi-layer composites for photoelectrochemical water splitting is presented, and a series of systematic experiments designed to elucidate the mechanism underlying the interfacial coupling effect of the quaternary hematite composite.

TL;DR: It is found that Sn(S,Se) can form on the surface either because of stoichiometric deviation or by condensation, and a phenomenological model is proposed for this passivation, which may open new perspectives for the development of CZTSSe-based solar cells.

Abstract: A spike-like conduction band alignment of kesterite absorbers with a CdS buffer layer is one of the key factors for high-performance solar cells using this buffer/absorber heterojunction combination. However, it can also be the origin of fill factor and current-reducing distortions in current–voltage curves, such as light/dark curve crossover, or an s-like curve shape for long wavelength monochromatic illumination (red kink) if light-dependent defect states are present in the buffer layer. In this work, we show that by changing the cadmium precursor source from sulfate to nitrate salts for the chemical bath deposited cadmium sulfide for Cu2ZnSnSnSe4/CdS heterojunction solar cells red kink can be eliminated, and crossover greatly improved (and eliminated entirely after light soaking). These improvements lead to a decrease in series resistance and an increase in fill factor and increase power conversion efficiency from 7.0% to 8.2%. We attribute this improvement to a reduction of deep level acceptor-like traps states inside the CdS layer, which are responsible for an increase of the conduction band spike up to a current blocking value for the sulfate precursor case. Furthermore, the effects of light soaking will be discussed. Copyright © 2015 John Wiley & Sons, Ltd.