Low-cost air-stable perovskite solar cells by incorporating inorganic materials

Herein, we demonstrate a new fabrication strategy for low-cost and stable-operation perovskite solar cells (PSCs) suitable for commercialization.

Alkali-metal-ion-doping strategy to improve the photovoltaic properties of Ag2BiI5 solar cells

An efficient alkali-metal-ion-doping strategy is proposed to improve the photovoltaic properties of Ag₂BiI₅ solar cells.

The structural properties of silicon-doped DBrTBT/ZnSe solar cell materials: a theoretical study

A new molecular design for solar cell materials is reported for the silicon-doped 4,7-di(5-bromothiophen-2-yl)-2,1,3-benzothiadiazole adsorbed on ZnSe(100) and ZnSe(111) surfaces.

First-Principles Study of Ferroelastic Twins in Halide Perovskites

We present an ab initio simulation of 90° ferroelastic twins that were recently observed in methylammonium lead iodide. There are two inequivalent types of 90° walls that we calculate to act as either electron or hole sinks, which leads us to propose a mechanism for enhancing charge carrier separation in photovoltaic devices. Despite separating nonpolar domains, we show these walls to have a substantial in-plane polarization of ∼6 μC cm^-2, due in part to flexoelectricity. We suggest this in turn could allow for the photoferroic effect and create efficient pathways for photocurrents within the wall.

TiO₂ Photocatalysis for Transfer Hydrogenation

Catalytic transfer hydrogenation reactions, based on hydrogen sources other than gaseous H₂, are important processes that are preferential in both laboratories and factories. However, harsh conditions, such as high temperature, are usually required for most transition-metal catalytic and organocatalytic systems. Moreover, non-volatile hydrogen donors such as dihydropyridinedicarboxylate and formic acid are often required in these processes which increase the difficulty in separating products and lowered the whole atom economy. Recently, TiO₂ photocatalysis provides mild and facile access for transfer hydrogenation of C=C, C=O, N=O and C-X bonds by using volatile alcohols and amines as hydrogen sources. Upon light excitation, TiO₂ photo-induced holes have the ability to oxidatively take two hydrogen atoms off alcohols and amines under room temperature. Simultaneously, photo-induced conduction band electrons would combine with these two hydrogen atoms and smoothly hydrogenate multiple bonds and/or C-X bonds. It is heartening that practices and principles in the transfer hydrogenations of substrates containing C=C, C=O, N=O and C-X bond based on TiO₂ photocatalysis have overcome a lot of the traditional thermocatalysis' limitations and flaws which usually originate from high temperature operations. In this review, we will introduce the recent paragon examples of TiO₂ photocatalytic transfer hydrogenations used in (1) C=C and C≡C (2) C=O and C=N (3) N=O substrates and in-depth discuss basic principle, status, challenges and future directions of transfer hydrogenation mediated by TiO₂ photocatalysis.

Lead-free hybrid perovskites for photovoltaics

This review covers the state-of-the-art in organo-inorganic lead-free hybrid perovskites (HPs) and applications of these exciting materials as light harvesters in photovoltaic systems. Special emphasis is placed on the influence of the spatial organization of HP materials both on the micro- and nanometer scale on the performance and stability of perovskite-based solar light converters. This review also discusses HP materials produced by isovalent lead(II) substitution with Sn2+ and other metal(II) ions, perovskite materials formed on the basis of M3+ cations (Sb3+, Bi3+) as well as on combinations of M+/M3+ ions aliovalent to 2Pb2+ (Ag+/Bi3+, Ag+/Sb3+, etc.). The survey is concluded with an outlook highlighting the most promising strategies for future progress of photovoltaic systems based on lead-free perovskite compounds.

Graphene-Based Inverted Planar Perovskite Solar Cells: Advancements, Fundamental Challenges, and Prospects

Metal halide based perovskite solar cells (PSCs) are considered among the most promising photovoltaic technologies, and already present certified efficiencies that surpass 22 %. The high performance and low fabrication cost make this technology competitive with that of state-of-the-art thin-film photovoltaics. However, PSCs present some striking disadvantages that hinder their commercialization, including short operational lifetimes, high toxicity, and hysteresis effects, which lower both the performance and long-term stability of the devices. Herein, work conducted within the last two years is summarized with regard to addressing the challenges of low-temperature-processed planar inverted PSCs composed of graphene-based materials. In addition, critical challenges and the prospects of this field are discussed and some prospects for future research directions are proposed.

A theoretical study of perovskites related to CH3NH3PbX3(X = F, Cl, Br, I)

MAPIand related perovskites have been studied using a hybrid DFT/HF DFT method with a simplified “corner” model. Bond dissociation energies and¹H,¹³C,¹⁵N and²⁰⁷Pb absolute shieldings were calculated.

Unexpected high binding energy of CO2 on CH3NH3PbI3 lead-halide organic–inorganic perovskites via bicarbonate formation

The adsorption kinetics of CO₂ was experimentally characterized in ultra-high vacuum (UHV). In addition, density functional theory (DFT) calculations were included.

Near-infrared-excitable perovskite quantum dots via coupling with upconversion nanoparticles for dual-model anti-counterfeiting

Upconversion nanoparticle-coupled perovskite quantum dots give efficient emissions under single near-infrared excitation.