Self-assembled materials with an ordered hydrophilic bilayer for high performance inverted Perovskite solar cells.

While self-assembled material based inverted perovskite solar cells have surpassed power conversion efficiencies of 26%, enhancing their performance in large-area configurations remains a significant challenge. In this work, we report a self-assembled material based hole-selective layer 4-(7H-dibenzo[c,g]carbazol-7-yl)phenyl)phosphonic acid, with a π-expanded conjugation. The enhanced intermolecular π-π interactions facilitate the self-assembly of 4-(7H-dibenzo[c,g]carbazol-7-yl)phenyl)phosphonic acid molecules to form an ordered bilayer with a hydrophilic surface, which passivates the buried perovskite interface defect and enables high-quality and large-area perovskite preparation, while simultaneously enhancing interfacial charge extraction and transport.

An Intermediate-Aided Perovskite Phase Purification for High-Performance Solar Cells.

In recent years, perovskite solar cells (PSCs) have garnered considerable attention as a prime candidate for next-generation photovoltaic technology. Ensuring the structural stability of perovskites is crucial to the operational reliability of these devices. However, the nonphotoactive yellow phase (δ-FAPbI) of formamidine (FA)-based perovskites is more favorable in thermodynamics, making it challenging to achieve pure α phase in crystallization.

Ultrathin polymer membrane for improved hole extraction and ion blocking in perovskite solar cells.

Highly efficient perovskite solar cells (PSCs) in the n-i-p structure have demonstrated limited operational lifetimes, primarily due to the layer-to-layer ion diffusion in the perovskite/doped hole-transport layer (HTL) heterojunction, leading to conductivity drop in HTL and component loss in perovskite. Herein, we introduce an ultrathin (~7 nm) p-type polymeric interlayer (D18) with excellent ion-blocking ability between perovskite and HTL to address these issues. The ultrathin D18 interlayer effectively inhibits the layer-to-layer diffusion of lithium, methylammonium, formamidium, and iodide ions.

Small-Molecule Hole Transport Materials for >26% Efficient Inverted Perovskite Solar Cells.

Chemically modifiable small-molecule hole transport materials (HTMs) hold promise for achieving efficient and scalable perovskite solar cells (PSCs). Compared to emerging self-assembled monolayers, small-molecule HTMs are more reliable in terms of large-area deposition and long-term operational stability. However, current small-molecule HTMs in inverted PSCs lack efficient molecular designs that balance both the charge transport capability and interface compatibility, resulting in a long-standing stagnation of power conversion efficiency (PCE) below 24.

Molecularly tailorable metal oxide clusters ensured robust interfacial connection in inverted perovskite solar cells.

Interfacial recombination and ion migration between perovskite and electron-transporting materials have been the persisting challenges in further improving the efficiency and stability of perovskite solar cells (PVSCs). Here, we design a series of molecularly tailorable clusters as an interlayer that can simultaneously enhance the interaction with C and perovskite. These clusters have precisely controlled structures, decent charge carrier mobility, considerable solubility, suitable energy levels, and functional ligands, which can help passivate perovskite surface defects, form a uniform capping net to immobilize C, and build a robust coupling between perovskite and C.

Buried Interface Modification Toward Efficient CsPbIBr Based Monolithic Perovskite/Organic Tandem Solar Cells.

Wide-bandgap perovskite sub-cells (WPSCs), one of the most crucial components of perovskite-based tandem solar cells (PTSCs), play a critical role in determining the performance of tandem devices. However, confined by the compromised crystallization properties of wide-bandgap perovskites, WPSCs exhibit significantly lower efficiency than their theoretical limit. In particular, for n-i-p structured all-inorganic WPSCs (AIWPSCs), severe nonradiative recombination due to the buried interface defects severely decreases the photovoltaic performance.

Local Structure-Induced Selective Interactions Enables High-Performance and Burn-in-Free Organic Photovoltaics.

Oligomeric acceptors (OAs) have attracted considerable attention in the organic photovoltaics (OPV) field owing to their capacity in balancing the merits from both monomeric and polymeric acceptors. A delicate control over the distortion between blocks of OAs usually determines the performance and stability of relevant OPV devices. However, it imposes great complexity to realize a controllable degree of distortion by tuning the skeleton of blocks and the position of linker between blocks.

Rational Design of A-Site Cation for High Performance Lead-Free Perovskite X-Ray Detectors.

Design of hypotoxic lead-free perovskites, e.g. Bismuth(Bi)-based perovskites, is much beneficial for commercialization of perovskite X-ray detectors due to their strong radiation absorption.

Multifunctional Buffer Layer Engineering for Efficient and Stable Wide-Bandgap Perovskite and Perovskite/Silicon Tandem Solar Cells.

Inverted perovskite solar cells (PSCs) are preferred for tandem applications due to their superior compatibility with diverse bottom solar cells. However, the solution processing and low formation energy of perovskites inevitably lead to numerous defects at both the bulk and interfaces. We report a facile and effective strategy for precisely modulating the perovskite by incorporating AlO deposited by atomic layer deposition (ALD) on the top interface.

Efficient and Stable Inverted Perovskite Solar Modules Enabled by Solid-Liquid Two-Step Film Formation.

A considerable efficiency gap exists between large-area perovskite solar modules and small-area perovskite solar cells. The control of forming uniform and large-area film and perovskite crystallization is still the main obstacle restricting the efficiency of PSMs. In this work, we adopted a solid-liquid two-step film formation technique, which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovskite films.

Dimensional Regulation from 1D/3D to 2D/3D of Perovskite Interfaces for Stable Inverted Perovskite Solar Cells.

Constructing low-dimensional/three-dimensional (LD/3D) perovskite solar cells can improve efficiency and stability. However, the design and selection of LD perovskite capping materials are incredibly scarce for inverted perovskite solar cells (PSCs) because LD perovskite capping layers often favor hole extraction and impede electron extraction. Here, we develop a facile and effective strategy to modify the perovskite surface by passivating the surface defects and modulating surface electrical properties by incorporating morpholine hydriodide (MORI) and thiomorpholine hydriodide (SMORI) on the perovskite surface.

Selenium substitution for dielectric constant improvement and hole-transfer acceleration in non-fullerene organic solar cells.

Dielectric constant of non-fullerene acceptors plays a critical role in organic solar cells in terms of exciton dissociation and charge recombination. Current acceptors feature a dielectric constant of 3-4, correlating to relatively high recombination loss. We demonstrate that selenium substitution on acceptor central core can effectively modify molecule dielectric constant.

Top-Down Induced Crystallization Orientation toward Highly Efficient p-i-n Perovskite Solar Cells.

Crystallization orientation plays a crucial role in determining the performance and stability of perovskite solar cells (PVSCs), whereas effective strategies for realizing oriented perovskite crystallization is still lacking. Herein, a facile and efficient top-down strategy is reported to manipulate the crystallization orientation via treating perovskite wet film with propylamine chloride (PACl) before annealing. The PA ions tend to be adsorbed on the (001) facet of the perovskite surface, resulting in the reduced cleavage energy to induce (001) orientation-dominated growth of perovskite film and then reduce the temperature of phase transition, meanwhile, the penetrating Cl ions further regulate the crystallization process.

Efficient all-small-molecule organic solar cells processed with non-halogen solvent.

All-small-molecule organic solar cells with good batch-to-batch reproducibility combined with non-halogen solvent processing show great potential for commercialization. However, non-halogen solvent processing of all-small-molecule organic solar cells are rarely reported and its power conversion efficiencies are very difficult to improve. Herein, we designed and synthesized a small molecule donor BM-ClEH that can take advantage of strong aggregation property induced by intramolecular chlorine-sulfur non-covalent interaction to improve molecular pre-aggregation in tetrahydrofuran and corresponding micromorphology after film formation.