Reducing nonradiative recombination for highly efficient inverted perovskite solar cells via a synergistic bimolecular interface.

Reducing interface nonradiative recombination is important for realizing highly efficient perovskite solar cells. In this work, we develop a synergistic bimolecular interlayer (SBI) strategy via 4-methoxyphenylphosphonic acid (MPA) and 2-phenylethylammonium iodide (PEAI) to functionalize the perovskite interface. MPA induces an in-situ chemical reaction at the perovskite surface via forming strong P-O-Pb covalent bonds that diminish the surface defect density and upshift the surface Fermi level.

Enhancing perovskite-silicon tandem solar cells through numerical optical and electric optimizations for light management.

We integrated optical and electrical numerical simulations to precisely investigate the effectiveness of using a pyramidal perovskite (CsFAPb(I,Br)) nanostructured film as an example in perovskite-silicon tandem solar cells to reduce reflective losses and balance the current densities. Through our calculations, the PCE of tandem solar cells can be improved from 29.2% (the planar structures without texturing) to 36.

A ferroelectric fin diode for robust non-volatile memory.

Among today's nonvolatile memories, ferroelectric-based capacitors, tunnel junctions and field-effect transistors (FET) are already industrially integrated and/or intensively investigated to improve their performances. Concurrently, because of the tremendous development of artificial intelligence and big-data issues, there is an urgent need to realize high-density crossbar arrays, a prerequisite for the future of memories and emerging computing algorithms. Here, a two-terminal ferroelectric fin diode (FFD) in which a ferroelectric capacitor and a fin-like semiconductor channel are combined to share both top and bottom electrodes is designed.

Passivating Dipole Layer Bridged 3D/2D Perovskite Heterojunction for Highly Efficient and Stable p-i-n Solar Cells.

Constructing 3D/2D perovskite heterojunction is a promising approach to integrate the benefits of high efficiency and superior stability in perovskite solar cells (PSCs). However, in contrast to n-i-p architectural PSCs, the p-i-n PSCs with 3D/2D heterojunction have serious limitations in achieving high-performance as they suffer from a large energetic mismatch and electron extraction energy barrier from a 3D perovskite layer to a 2D perovskite layer, and serious nonradiative recombination at the heterojunction. Here a strategy of incorporating a thin passivating dipole layer (PDL) onto 3D perovskite and then depositing 2D perovskite without dissolving the underlying layer to form an efficient 3D/PDL/2D heterojunction is developed.

Industrial Kraft Lignin Based Binary Cathode Interface Layer Enables Enhanced Stability in High Efficiency Organic Solar Cells.

Herein, a binary cathode interface layer (CIL) strategy based on the industrial solvent fractionated LignoBoost kraft lignin (KL) is adopted for fabrication of organic solar cells (OSCs). The uniformly distributed phenol moieties in KL enable it to easily form hydrogen bonds with commonly used CIL materials, i.e.

Revealing Charge-Transfer Dynamics at Buried Charge-Selective Heterointerface in Highly Effective Perovskite Solar Cells.

The suboptimal carrier dynamics at the heterointerface between the perovskite and charge transport layer severely limit further performance enhancement of the state-of-the-art perovskite solar cells (PSCs). Herein, we completely map charge carrier extraction and recombination kinetics over a broad time range at buried electron-selective heterointerfaces via ultrafast transient technologies. It is revealed that the heterointerfaces carefully contain the electronic processes of free charge generation in perovskite within ∼2.

4-Terminal Inorganic Perovskite/Organic Tandem Solar Cells Offer 22% Efficiency.

After fast developing of single-junction perovskite solar cells and organic solar cells in the past 10 years, it is becoming harder and harder to improve their power conversion efficiencies. Tandem solar cells are receiving more and more attention because they have much higher theoretical efficiency than single-junction solar cells. Good device performance has been achieved for perovskite/silicon and perovskite/perovskite tandem solar cells, including 2-terminal and 4-terminal structures.

Constructing Chromium Multioxide Hole-Selective Heterojunction for High-Performance Perovskite Solar Cells.

Perovskite solar cells (PSCs) suffer from significant nonradiative recombination at perovskite/charge transport layer heterojunction, seriously limiting their power conversion efficiencies. Herein, solution-processed chromium multioxide (CrO ) is judiciously selected to construct a MAPbI /CrO /Spiro-OMeTAD hole-selective heterojunction. It is demonstrated that the inserted CrO not only effectively reduces defect sites via redox shuttle at perovskite contact, but also decreases valence band maximum (VBM)-HOMO offset between perovskite and Spiro-OMeTAD.

A Transparent Electrode Based on Solution-Processed ZnO for Organic Optoelectronic Devices.

Achieving high-efficiency indium tin oxide (ITO)-free organic optoelectronic devices requires the development of high-conductivity and high-transparency materials for being used as the front electrode. Herein, sol-gel-grown zinc oxide (ZnO) films with high conductivity (460 S cm) and low optical absorption losses in both visible and near-infrared (NIR) spectral regions are realized utilizing the persistent photoinduced doping effect. The origin of the increased conductivity after photo-doping is ascribed to selective trapping of photogenerated holes by oxygen vacancies at the surface of the ZnO film.

Surface Passivation and Energetic Modification Suppress Nonradiative Recombination in Perovskite Solar Cells.

Surface passivation via post-treatment is an important strategy for improving power conversion efficiency and operational stability of perovskite solar cells. However, so far the interaction mechanisms between passivating additive and perovskite are not well understood. Here, we report the atomic-scale interaction of surface passivating additive 2,2-difluoroethylammonium bromine (2FEABr) on the MAPbI.

Li-Doped ZnO Electron Transport Layer for Improved Performance and Photostability of Organic Solar Cells.

Organic solar cells (OSCs) based on an inverted architecture generally have better stability compared to those based on a standard architecture. However, the photoactive area of the inverted solar cells increases under ultraviolet (UV) or solar illuminatiom because of the too-high conductivity of the UV-illuminated zinc oxide (ZnO) interlayer. This limits the potential of the inverted solar cells for industrial applications.

Plasmon-coupled Au-nanochain functionalized PEDOT:PSS for efficient mixed tin-lead iodide perovskite solar cells.

Au nanochains with a coupled plasmonic nanostructure were first introduced into PEDOT:PSS used as a hole transport layer to fabricate mixed tin-lead PSCs. The improved electrical properties and the promotion of optical absorption contributed to a high PCE of 19.2%.

Chlorination Enabling a Low-Cost Benzodithiophene-Based Wide-Bandgap Donor Polymer with an Efficiency of over 17.

Three regioregular benzodithiophene-based donor-donor (D-D)-type polymers (PBDTT, PBDTT1Cl, and PBDTT2Cl) are designed, synthesized, and used as donor materials in organic solar cells (OSCs). Because of the weak intramolecular charge-transfer effect, these polymers exhibit large optical bandgaps (>2.0 eV).

Perovskite-based tandem solar cells.

The power conversion efficiency for single-junction solar cells is limited by the Shockley-Quiesser limit. An effective approach to realize high efficiency is to develop multi-junction cells. These years have witnessed the rapid development of organic-inorganic perovskite solar cells.

Universal and versatile morphology engineering via hot fluorous solvent soaking for organic bulk heterojunction.

After explosive growth of efficiency in organic solar cells (OSCs), achieving ideal morphology of bulk heterojunction remains crucial and challenging for advancing OSCs into consumer market. Herein, by utilizing the amphiphobic nature and temperature-dependent miscibility of fluorous solvent, hot fluorous solvent soaking method is developed to optimize the morphology with various donor/acceptor combinations including polymer/small-molecule, all-polymer and all-small-molecule systems. By immersing blend film into hot fluorous solvent which is utilized as liquid medium with better thermal conductivity, the molecular reorganization is accelerated.

Effect of the Energy Offset on the Charge Dynamics in Nonfullerene Organic Solar Cells.

The energy offset, considered as the driving force for charge transfer between organic molecules, has significant effects on both charge separation and charge recombination in organic solar cells. Herein, we designed material systems with gradually shifting energy offsets, including both positive and negative values. Time-resolved spectroscopy was used to monitor the charge dynamics within the bulk heterojunction.

A Fully Non-fused Ring Acceptor with Planar Backbone and Near-IR Absorption for High Performance Polymer Solar Cells.

Fused-ring electron acceptors have made significant progress in recent years, while the development of fully non-fused ring acceptors has been unsatisfactory. Here, two fully non-fused ring acceptors, o-4TBC-2F and m-4TBC-2F, were designed and synthesized. By regulating the location of the hexyloxy chains, o-4TBC-2F formed planar backbones, while m-4TBC-2F displayed a twisted backbone.

General Construction of 2D Ordered Mesoporous Iron-Based Metal-Organic Nanomeshes.

Nanomeshes with highly regular, permeable pores in plane, combining the exceptional porous architectures with intrinsic properties of 2D materials, have attracted increasing attention in recent years. Herein, a series of 2D ultrathin metal-organic nanomeshes with ordered mesopores is obtained by a self-assembly method, including metal phosphate and metal phosphonate. The resultant mesoporous ferric phytate nanomeshes feature unique 2D ultrathin monolayer morphologies (≈9 nm thickness), hexagonally ordered, permeable mesopores of ≈16 nm, as well as improved surface area and pore volume.

Enhanced and Balanced Charge Transport Boosting Ternary Solar Cells Over 17% Efficiency.

Ternary architecture is one of the most effective strategies to boost the power conversion efficiency (PCE) of organic solar cells (OSCs). Here, an OSC with a ternary architecture featuring a highly crystalline molecular donor DRTB-T-C4 as a third component to the host binary system consisting of a polymer donor PM6 and a nonfullerene acceptor Y6 is reported. The third component is used to achieve enhanced and balanced charge transport, contributing to an improved fill factor (FF) of 0.

Pre-Polymerization Enables Controllable Synthesis of Nanosheet-Based Porphyrin Polymers towards High-Performance Li-Ion Batteries.

The precise regulation of nucleation growth and assembly of polymers is still an intriguing goal but an enormous challenge. In this study, we proposed a pre-polymerization strategy to regulate the assembly and growth of polymers by facilely controlling the concentration of polymerization initiator, and thus obtained two kinds of different nanosheet-based porphyrin polymer materials using tetrakis-5,10,15,20-(4-aminophenyl) porphyrin (TAPP) as the precursor. Notably, due to the π-π stacking and doping of TAPP during the preparation process, the obtained PTAPP-nanocube material exhibits a high intrinsic bulk conductivity reaching 1.

Low-Temperature Aging Provides 22% Efficient Bromine-Free and Passivation Layer-Free Planar Perovskite Solar Cells.

Previous reports of formamidinium/methylamine (FAMA)-mixed halide perovskite solar cells have focused mainly on controlling the morphology of the perovskite film and its interface-for example, through the inclusion of bromine and surface passivation. In this paper, we describe a new processing pathway for the growth of a high-quality bromine-free FAMAPbI halide perovskites via the control of intermediate phase. Through low-temperature aging growth (LTAG) of a freshly deposited perovskite film, α-phase perovskites can be seeded in the intermediate phase and, at the same time, prevent beta-phase perovskite to nucleate.