Dimethyl Ferrocene-Induced Ambient-Processed High-Quality Films toward Efficient Perovskite Solar Cells for Industrial Application.

Metal halide perovskite solar cells (PSCs) have recently made significant progress with power conversion efficiencies (PCEs) boosted from 3.8% to a certified one over 26.1%, partially benefiting from the high-quality perovskite film enabled by the effective one-step spin-coating route.

Built-in Electric Field in Quasi-2D CsPbI Perovskites Using High-Polarized Zwitterionic Spacer for Enhanced Charge Separation/Transport.

Two-dimensional (2D) halide perovskites are promising candidates for the fabrication of stable and high-efficiency solar cells. However, the low power conversion efficiency (PCE) of cell devices using 2D perovskites is attributed to reduced charge transport caused by poor organic barrier conductivity. In this study, we propose the use of a high-polarized organic zwitterionic spacer, -aminobenzoic acid (PABA), to construct novel quasi-2D perovskite structures with enhanced self-driven charge separation and transfer.

Energy Level Matching and Band Edge Reconfiguration for Enhanced Charge Transport in Dion-Jacobson 3D/2D Perovskite Heterojunctions.

Generally, the 2D CsPbI layer capping on 3D counterparts has been considered as an effective strategy for both enhancing photovoltaic efficiency and stability. However, the intrinsically poor out-of-plane charge transport through the 2D layer remarkably hinders the overall performance of solar devices. To overcome such a challenge, we report the rationally designed 3D-CsPbI/2D-(PY)PbI ( = 1-4) heterojunctions with desirable energy level matching.

Improving Out-of-Plane Charge Mobility and Phase Stability of Dion-Jacobson Lead-Free Perovskites via Intercalating π-Conjugated Aromatic Spacers.

The layered quasi-2D perovskites are recognized as one of the effective strategies to resolve the big problem of intrinsic phase instability of the perovskites. However, in such configurations, their performance is fundamentally limited due to the correspondingly weakened out-of-plane charge mobility. Herein, the π-conjugated p-phenylenediamine (PPDA) is introduced as organic ligand ions for rationally designing lead-free and tin-based 2D perovskites with the aid of theoretical computation.

Enhancing the Stability of Orthorhombic CsSnI Perovskite Oriented π-Conjugated Ligand Passivation.

Lead-free orthorhombic CsSnI (Bγ-CsSnI) perovskite has been emerging as one of the potential candidates of photovoltaic materials with superior performance. However, the instability induced by rapid reconstructive phase transition and the oxidation of Sn greatly limits their future application. We thus reported a strategy, oriented π-conjugated ligand passivation, for enhancing the stability of Bγ-CsSnI, simulated using a Bγ-CsSnI slab model based on the first-principles computation.

Stable Bandgap-Tunable Hybrid Perovskites with Alloyed Pb-Ba Cations for High-Performance Photovoltaic Applications.

The intrinsic poor stability of MAPbI hybrid perovskites in the ambient environment remains as the major challenge for photovoltaic applications. In this work, complementary first-principles calculations and experimental characterizations reveal that metal cation alloyed perovskite (MABa PbI) can be synthesized and exhibit substantially enhanced stability via forming stronger Ba-I bonds. The Ba-Pb alloyed perovskites remain phase-pure in ambient air for more than 15 days.

Elimination of S Vacancy as the Cause for the n-Type Behavior of MoS from the First-Principles Perspective.

Molybdenum disulfide (2H-MoS) based low-dimensional nanostructure materials have great potential for applications in electronic and optoelectronic devices. However, some of the properties such as the origin of the native n-type electrical conductivity (EC) observed in these materials still remain elusive. Here, the defect properties in the 2H-MoS bulk system are systematically investigated by first-principles calculation to address these issues.

Recoil effects in valence band photoemission of organic solids.

Recoil effects in valence band X-ray photoelectron spectroscopy (XPS) are studied for both abb-trifluorostyrene and styrene molecular crystal systems. The gradual changes of XPS spectra excited by several photon energies are theoretically investigated within the tight-binding approximation and harmonic approximation of lattice vibrations and have been explained in terms of not only atomic mass but also atomic orbital (AO) population. The recoil effect of valence band photoemission strongly depends on the population and partial photoionization cross section (PICS) of AOs as well as the masses of composite atoms.