The buried interface between self-assembled monolayers (SAMs) and perovskite absorbers critically governs charge extraction and stability in inverted perovskite solar cells, yet remains structurally mismatched and poorly controlled. Here, we report a buried-interface engineering strategy inspired by non‑covalent molecular templating, enabled by complementary triphenylamine-based molecular building blocks. A triphenylamine-based ammonium salt, 2-(4-(diphenylamino)phenyl)ethanammonium iodide (TPANI), is introduced into the perovskite precursor, while a structurally matched triphenylamine-based bisphosphonic acid SAM deposited on ITO serves as the hole-selective layer. Non-covalent interactions at the buried interface induce molecular templating and interfacial organization of TPANI, strengthening SAM/perovskite adhesion and reducing intergranular groove depth at the buried side of the perovskite film. The resulting monolithically integrated interface suppresses buried interfacial defects, improves energy-level alignment, and facilitates hole extraction. Consequently, inverted devices achieve a power conversion efficiency of 26.58% with an exceptionally high fill factor of 86.72%, together with markedly enhanced operational stability. These results demonstrate that non‑covalent molecular templating provides an effective and general strategy for engineering buried interfaces in perovskite photovoltaics.

Light-emitting colloidal lead halide perovskite nanocrystals (PeNCs) are considered promising candidates for next-generation vivid displays. However, the operational stability of light-emitting diodes (LEDs) based on PeNCs is still lower than those based on polycrystalline perovskite films, which requires an understanding of defect formation in PeNCs, both inside the crystal lattice ("bulk") and at the surface. Meanwhile, uncontrollable ion redistribution and electrochemical reactions under LED operation can be severe, which is also related to the bulk and surface quality of PeNCs, and a well-designed device architecture can boost carrier injection and balance radiative recombination. In this review, we consider bulk and surface reconstruction of PeNCs by enhancing the crystal lattice rigidity and rationally selecting the surface ligands. Degradation pathways of PeNCs under applied voltage are discussed, and strategies are considered to avoid both undesirable ion migration and electrochemical reactions in the PeNC films. Subsequently, other critical issues hindering the commercial application of PeNC LEDs are discussed, including the toxicity of Pb in lead halide perovskites, scale-up deposition of PeNC films, and design of active-matrix prototypes for high-resolution LED modules.

Chemically modifiable self-assembled monolayer (SAM)-based hole transport layers are crucial for achieving high-efficiency inverted perovskite solar cells (PSCs). However, designing molecular structures that simultaneously ensure strong binding affinity, interfacial stability, and optimized energy level alignment remains challenging. Here, we introduce TPA2P ((2-(4-(diphenylamino)phenyl)-1-phosphonovinyl)phosphonic acid), a novel SAM material featuring a conjugated bisphosphonic acid anchoring group. This dual phosphonic acid configuration enhances substrate binding on indium tin oxide (ITO), improves SAM uniformity, and increases interfacial stability. Furthermore, the ethylene bridge facilitates efficient intramolecular charge transfer (ICT) from the electron-donating triphenylamine unit to the electron-accepting bisphosphonic acid group. This ICT induces significant charge redistribution in TPA2P, resulting in a deep HOMO level at -5.47 eV. This optimized energy alignment reduces interfacial energy losses and significantly enhances hole extraction efficiency. As a result, TPA2P-based inverted PSCs achieve a high power conversion efficiency of 26.11%, an exceptional fill factor of 85.03%, and outstanding operational stability under continuous illumination. These findings provide an effective molecular design strategy for advancing high-performance and stable perovskite photovoltaics.

The PEDOT:PSS has been utilized extensively as a hole transport layer (HTL) in organic solar cells (OSCs) due to its excellent compatibility with various bulk heterojunction (BHJ) active layers. However, its intrinsically low electrical conductivity and suboptimal surface morphology limit hole extraction, ultimately constraining the performance of OSCs. To address this, we constructed an advanced heterojunction interface by introducing a wide-bandgap perovskite (CsPbBr3) interlayer between the PEDOT:PSS and BHJ. The textured CsPbBr3 interlayer serves as an efficient hole transport modifier by enhancing extraction and transport efficiency, while simultaneously functioning as an energy donor via Förster resonance energy transfer (FRET) and as a photosensitizer capable of generating photocarriers independently through its intrinsic optoelectronic properties. This synergetic enhancement of charge generation, extraction, and transport properties resulted in an increase in the power conversion efficiency (PCE) of PM6:Y6-based OSCs from 16.80% to 17.74%, along with improved photocurrent and fill factor (FF). The universality of this approach was further demonstrated in state-of-the-art PM6:BTP-eC9:L8-BO systems, achieving a PCE of 19.02%. Our work elucidates the multifunctional role of CsPbBr3 in managing interfacial properties, presenting a feasible interface engineering strategy to achieve high-performance OSCs.

The application of carbazole phosphonic acid (CPA) molecules for interfacial modification in optoelectronic devices is often constrained by poor solubility in non-polar solvents, limiting their processability. To address this issue, a novel CPA molecule, (4-(3,6-bis(7H-dibenzo[c,g]carbazol-7-yl)-9H-carbazol-9-yl)butyl)phosphonic acid (BFC-BPA), is synthesized, featuring an optimized molecular structure. This design incorporates carbazole and 7H-dibenzo[c,g]carbazole as terminal groups, linked by a four-carbon chain, with phosphonic acid functioning as the anchoring group. BFC-BPA exhibits excellent solubility in chlorobenzene (CB), enabling efficient blending with poly(9-vinylcarbazole) (PVK) to form a hybrid hole transport layer (HTL). This integration enhances the NiOx/HTL interface and improves the wettability of the organic HTL, facilitating the formation of high-quality quasi-2D perovskite films with superior crystallinity. The hybrid HTL not only regulates hole injection and transport but also ensures balanced charge transport in perovskite light-emitting diodes (PeLEDs). This synergistic design enables high-efficiency sky-blue PeLEDs, achieving a maximum external quantum efficiency (EQE) of 18.57% and an average EQE increase from 6.94% to 17.01%, compared to bare PVK-based devices. This study highlights the importance of rational molecular design in overcoming solubility challenges, enhancing CPA functional versatility, and expanding their potential applications in advanced optoelectronic devices.

Solution-processed metal halide perovskites are widely studied for their potential in high-efficiency light-emitting diodes, yet they are facing several challenges like insufficient brightness, short operational lifetimes, and reduced power conversion efficiency under practical operation conditions. Here, we develop an interfacial amidation reaction on sacrificial ZnO substrates to produce perovskite films with low trap density (1.2 × 1010 cm−3), and implement a device structure featuring a mono-molecular hole-injection layer and an all-inorganic bi-layered electron-injection layer. This design leads to green perovskite light-emitting diodes with a brightness of ~ 312,000 cd m−2, a half-lifetime of 350 h at 1000 cd m−2, and a power conversion efficiency of 15.6% at a current density of 300 mA cm−2. Furthermore, the perovskite films show a low amplified spontaneous emission threshold of 13 μJ cm−2. Thus, our approach significantly advances the performance of green perovskite light-emitting diodes and opens up an avenue toward perovskite-based electrically pumped lasers. Chen et al. report an interfacial amidation reaction between perovskite precursor and pimelic acid on sacrificial ZnO substrates to fabricate 3D FAPbBr3 films with low trap density of 1.2E10 cm−3. The device structure is further optimised to achieve green LEDs with low efficiency roll-off.

Advances in improving the operational lifetime of highly efficient organic photovoltaic (OPV) and understanding photo-degradation mechanisms in molecular level are currently limited, especially on the promising inverted OPV, posing critical challenges to commercialization. Here, we demonstrate a radical scavenger (3-(3,5-Di-tert-butyl-4-hydroxyphenyl)propionic acid) capped ZnO (BHT@ZnO) nanoparticles as the electron transport layer providing effective surface oxygen vacancy passivation and reactive radical capture capability. Encouragingly, this BHT@ZnO-based empowered device achieves a record inverted OPV efficiency of 19.47% (Certificated efficiency: 18.97%). The devices demonstrate light soaking-free behavior, long-term stability under ISOS-D-1 (94.2% PCE retention after 8904 h in ambient) and ISOS-L-1 testing protocol (81.5% PCE retention after 7724 h in MPP). More importantly, we elucidate detailed degradation mechanism in OPV involving selectively catalytic degradation of donor and acceptor by superoxide and hydroxyl radicals, respectively, as well as the degradation pathway of polymer donor upon radiation exposure. Performance enhancement and mechanism comprehension provide strong support for the development of OPV technology.

Metal halide perovskites, known for their pure and tunable light emission, near-unity photoluminescence quantum yields, favorable charge transport properties, and excellent solution processability, have emerged as promising materials for large-area, high-performance light-emitting diodes (LEDs). Over the past decade, significant advancements have been made in enhancing the efficiency, response speed, and operational stability of perovskite LEDs. These promising developments pave the way for a broad spectrum of applications extending beyond traditional solid-state lighting and displays to include visible light communication (VLC) and lasing applications. This perspective evaluates the current state of perovskite LEDs in those emerging areas, addresses the primary challenges currently impeding the development of perovskite-based VLC systems and laser diodes, and provides an optimistic outlook on the future realization of perovskite-based VLC and electrically pumped perovskite lasers.

Carbazole phosphonic acids (CPAs) that are used in self-assembled monolayers (SAMs) are well-reported. Yet, an understanding of their broader application still needs to be fully established. In this work, we demonstrate that incorporating CPAs into blue quasi-2D perovskite precursors as additives is an effective strategy for fine-tuning phase distribution and enhancing the radiative characteristics of the resultant films. [2-(9H-Carbazol-9-yl)ethyl]phosphonic acid (2PACz) emerges as the most effective molecule for improving device performance. Significantly, when the perovskite film is deposited onto a hole injection structure of ITO/Mg0.1Ni0.9Ox/SAM/poly(9-vinylcarbazole) (PVK), 2PACz preferentially migrates to the PVK/perovskite interface. This phenomenon is driven by the strong interaction between the carbazole components of both PVK and 2PACz, leading to a stabilized interface. Coupled with the controlled phase distribution of the perovskite, this approach results in a marked increase in external quantum efficiency for blue perovskite LEDs, advancing from 11% to beyond 15%. These insights underscore the versatility of CPAs in the development of high-efficiency optoelectronic devices.

The development of advanced perovskite emitters has considerably improved the performance of perovskite light-emitting diodes (LEDs). However, the further development of perovskite LEDs requires ideal device electrical properties, which strongly depend on its interfaces. In perovskite LEDs with conventional p-i-n structures, hole injection is generally less efficient than electron injection, causing charge imbalance. Furthermore, the popular hole injection structure of NiO x /poly(9-vinylcarbazole) suffers from several issues, such as weak interfacial adhesion, high interfacial trap density and mismatched energy levels. In this work, we insert a self-assembled monolayer of [2-(9H-carbazol-9-yl)ethyl]phosphonic acid between the NiO x and poly(9-vinylcarbazole) layers to overcome these challenges at the organic/inorganic heterointerfaces by establishing a robust interface, passivating interfacial trap states and aligning the energy levels. We successfully demonstrate blue (emission at 493 nm) and green (emission at 515 nm) devices with external quantum efficiencies of 14.5% and 26.0%, respectively. More importantly, the self-assembled monolayer also gives rise to devices with much faster response speeds by reducing interfacial capacitance and resistance. Our results pave the way for developing more efficient and brighter perovskite LEDs with quick response, widening their potential application scope.

Metal halide perovskites are considered as promising candidates for lighting applications owing to their excellent optoelectronic properties, such as high electron/hole mobility, high photoluminescence quantum yield, high color purity, and facile color tunability. In recent years, perovskite light-emitting diodes (LEDs) have developed rapidly, and their external quantum efficiencies (EQEs) have exceeded 20% for green and red emissions. However, the EQEs and stabilities of blue (particularly deep-blue) perovskite LEDs are still inferior to the green and red counterparts, which severely restricts the application of perovskite LEDs in high-performance and wide color gamut displays as well as white light illumination. Therefore, summarizing the development of blue perovskite LEDs and discussing the opportunities and challenges associated with their future applications will help to guide the further development of the entire perovskite LED field. In this review, according to the emission color, we divide the blue perovskite LEDs into three parts for a better discussion, i.e., the emissions in the sky-blue, pure-blue, and deep-blue regions. We introduce their developed history and discuss the basic strategies to achieve blue emission. There are three typical methods to obtain perovskite emitters with blue emission, i.e., (1) composition engineering, (2) dimensional engineering, and (3) synthesis of perovskite nanocrystals and quantum dots. For composition engineering, changing ions in perovskite ABX3 structure can easily tune the perovskite emission color, particularly while changing the anions in "X" position. Therefore, modulating the ratio between the X-site anions of Br- and a- can cause perovskites to emit blue photons ranging from 420 to 490 nm, which almost covers the entire blue spectrum. For dimensional engineering, perovskite materials can form a series of low-dimensional structures (layered structures) with the insertion of organic ligands between the perovskite frameworks. This type of low-dimensional perovskite material typically exhibits better lighting properties than those exhibited by its three-dimensional counterpart owing to its unique charge or energy transfer process of charge carriers. Blue perovskite nanocrystals and quantum dots with high photoluminescence quantum yields are excellent candidates for realizing high-performance pure-blue and deep-blue devices because they can easily incorporate a- in their crystals, which is considerably limited in perovskite thin films owing to the poor solubility of inorganic chloride sources in polar solvents. Furthermore, we discuss several challenges associated with blue perovskite LEDs, such as the inferior device performance in the pure-blue and deep-blue regions, difficulty in hole injection, electroluminescence (EL) instability of mixed halide perovskite systems, and lagged operation lifetime, and introduce potential solutions accordingly. Note that the challenges faced by blue perovskite LEDs are also the opportunities for research in this area. Therefore, this review is of a great reference value for the next evolution of blue perovskite LEDs.

The inferior light extraction efficiency (LEE), which is generally less than 20%, based on optical modeling, and the difficulty in achieving white emission are the two main challenges in the metal-halide-perovskite light-emitting diode (PeLED) field. Herein, we report a simple and efficient approach to construct high-performance white PeLEDs with much-enhanced LEE by coupling a blue PeLED with a layer of red perovskite nanocrystal (PeNC) down-converter through a rationally designed multilayer semitransparent electrode (LiF/Al/Ag/LiF). The red PeNC layer allows the extraction of the trapped waveguide mode and surface plasmon polariton mode in a blue PeLED and converts them to red emission, resulting in over 50% LEE improvement. Simultaneously, the complementary emission spectrum of blue photons and down-converting red photons contributes to a white PeLED with a high external quantum efficiency and luminance of more than 12% and approximately 2,000 cd m(-2), respectively, which represent state-of-the-art results in this field.

Recent studies of sky‐blue perovskite light‐emitting diodes (PeLEDs) have extensively promoted optimal device design to achieve an external quantum efficiency (EQE) above 12%. However, the development of thin‐film deep‐blue PeLEDs lags dramatically behind, especially with regards to meeting the latest Rec. 2020 standard. A trichloro(3,3,3‐trifluoropropyl) silane post‐treatment that drives the emission of perovskite into the deep‐blue region, ranging from 440 to 460 nm, which meets the Rec. 2020 standard, is proposed. The chlorine ions released from the organotrichlorosilane molecules during their polycondensation reaction provide an addition halide source to fine tune the composition of the mixed halide perovskite films, leading to increase of bandgap and deep‐blue emission. In addition, hydrogen bonds between the hydroxy groups of silane molecules and halide anions in perovskite can suppress ion migration for improving emission stability. As a result, an optimal PeLED is developed with deep‐blue emission at 458 nm and excellent color stability, which yields an EQE and luminance of 1.1% and 130 cd m −2 , respectively, representing a state‐of‐the‐art result for thin‐film PeLEDs in this emission region. This work paves the way to achieve high‐performance deep‐blue PeLEDs with stable emissions to meet the demand for potential applications such as full‐color display.

In recent years, metal halide perovskites have received extensive attention due to their superior optoelectronic properties and solution processability, which also become a research hotspot in the field of optoelectronics. Among all the perovskite optoelectronics applications, perovskite light-emitting diode (LED) becomes one of the important research topics because it is likely to be used in the next-generation display technique. Based on the high photoluminescence quantum yield (PLQY), facilely tunable bandgaps, and sharp emission of perovskite material, the external quantum efficiency of perovskite LED has increased from less than 1% to over 20% within only five years, showing the most rapid development speed in the LED field. During the 5-year exploration of perovskite LEDs, researchers have focused their efforts on how to realize the crystal-growth control in the perovskite film formation process, enhance PLQY of the perovskite films, and improve the performance of perovskite LEDs. Among all the approaches, the utilization of organic additives including small molecules and polymers proves to be an effective strategy. Here, in this article, we review the recent advances in metal halide perovskite LEDs based on the strategy of organic-additive treatment. We also analyze and discuss the interaction between organic additive and perovskite crystal as well as its influence on the performance of perovskite LED. In the end, we discuss the challenges remaining in perovskite LEDs and the prospects for perovskite LEDs.