The construction of high-quality crystalline junctions is pivotal for unlocking the full potential of perovskite optoelectronics, yet it remains challenging, especially via solution processing in ambient air. Here, we demonstrate a rapid epitaxial growth strategy for fabricating orientation-controlled perovskite homojunctions using a solvent-mediated thermal-shock process. This air-based epitaxy leverages the synergy between thermal-shock-induced flash crystallization and the inverse temperature solubility of 2-methoxyethanol, which maintains interfacial stability while enabling directional growth, thus combining solution-processing simplicity with epitaxial precision. The resultant 3D/3D perovskite homojunction exhibits a highly consistent (001) orientation (Hermans’ orientation factor of −0.3643) and a low trap-state density. Consequently, the corresponding homojunction perovskite solar cell (PSC) achieves a remarkable power conversion efficiency of 25.58% with outstanding operational stability, maintaining 93%, 97%, and 94% of its initial efficiency under International Summit on Organic Photovoltaic Stability (ISOS)-D-1, ISOS-L-1I, and ISOS-D-2I protocols, respectively.

Controlling the photoluminescence and tunable luminescent chromaticity properties of inorganic phosphors is crucial for achieving high-security-level anti-counterfeiting and information encryption storage systems, remaining a persistent challenge. In this work, a dual-emission center construction strategy was used to modify silicate phosphors. The resulting K7Tb3Si12O32 & centerdot;4H2O:Eu3+(KTSO:Eu3+) phosphor displays tunable luminescence under different UV wavelength excitations while maintaining high stability. The energy-transfer process, governed by a multipolar interaction mechanism, proceeds efficiently from the active Tb3 + host framework to the Eu3+ ions residing in the structural channels. Furthermore, based on the optical signals of the KTSO:Eu3+ phosphor, this work designed a series of security identification and information encryption demonstrations for Changchun University of Science and Technology (CUST) and Jilin University (JLU), confirming the broad potential application prospects of these phosphors in the fields of anti-counterfeiting and information encryption.

Developing lead-free low-dimensional organic-inorganic metal halides (OIMHs) with highly efficient photoluminescence and superior stability is crucial for advancing next-generation solid-state lighting technologies. However, rationally selecting suitable organic molecules to precisely tailor their crystalline structures and photophysical properties remains a key challenge. Herein, we present the rational design and one-pot synthesis of two guanidinium-based manganese halides, namely [(Gua)(EA)]MnBr4 and (Gua)2MnBr4 (Gua+ = guanidinium, EA+ = ethylammonium), employing 1-ethyl-3-guanidinothiourea hydrochloride as the sole organic precursor. Single-crystal X-ray diffraction (SCXRD) analysis confirms that [(Gua)(EA)]MnBr4 features discrete tetrahedral [MnBr4]2- anions, whereas (Gua)2MnBr4 comprises face-sharing octahedral [Mn3Br12]6- trimeric clusters, both of which are stabilized by robust N- H & sdot;& sdot;& sdot;Br hydrogen-bonding networks. Photophysical characterization demonstrates that the distinct Mn2+ coordination configurations enable tunable luminescence, with [(Gua)(EA)]MnBr4 exhibiting green emission at 516 nm, and (Gua)2MnBr4 displaying red emission at 628 nm, both originating from the characteristic 4T1(G) -> 6A1(S) d-d transitions of Mn2+ ions. Notably, both Gua-based Mn-halides exhibit excellent ambient and thermal stability. By employing the green-emitting [(Gua)(EA)]MnBr4 and red-emitting (Gua)2MnBr4 as phosphors, we fabricated a UV-pumped white light-emitting diode (WLED) that achieves a correlated color temperature of 5897 K, a color rendering index of 88.8, and superior spectral stability, meeting the performance requirements for indoor lighting applications. This work presents a facile one-pot approach for the simultaneous synthesis of two functionally distinct hybrid Mn-halide crystals and further validates guanidine derivatives as versatile precursors, thereby offering an efficient and scalable strategy for constructing high-performance manganese halides for advanced solid-state lighting.

Perovskite materials have revolutionized optoelectronics by virtue of their tunable bandgaps, exceptional optoelectronic properties, and structural flexibility. Notably, the state-of-the-art performance of perovskite solar cells has reached 27%, making perovskite materials a promising candidate for next-generation photovoltaic technology. Although numerous reviews regarding perovskite materials have been published, the existing reviews generally focus on individual material systems (e.g., organic-inorganic hybrid perovskites) and specific optimizations in one particular optoelectronic application (e.g., stability engineering for solar cells), lacking a systematic overview of the progress and challenges across diverse perovskite types. This review breaks this limitation by providing a systematic overview of all perovskite categories used in solar cells classified by different criteria, including composition (organic-inorganic hybrid perovskites, all-inorganic perovskites, lead-free perovskites, and metal-free perovskites), dimensionality (3D and low-dimensional perovskitoids), and crystallinity (poly-crystal thin film and single-crystal perovskites). The recent progress and future perspectives for each category of perovskite solar cells are focused on, aiming to establish a holistic roadmap for perovskite solar cells toward technological innovations and industrial viability.

Organic-inorganic halide perovskite single crystals (SCs) have shown great potential in radiation detection applications due to their large radiation stopping power and excellent carrier transport properties. The spatial-confined inverse-temperature crystallization (ITC) method has been widely adopted to obtain large-sized SCs. However, they usually face the problems of uneven stress distribution and high defect density due to the limited crystal growth space and varied growth rate with the increase in temperature, making it difficult to fabricate highly sensitive and stable radiation detectors. In this study, the steady-state inverse-temperature crystallization method (SS-ITC) is developed to regulate the growth process of SCs by controlling the growth speed precisely to achieve a constant rate of growth as the temperature increases. Compared with the conventional ITC-grown samples, the lattice spacing of SCs prepared by the SS-ITC method is reduced by 1.2% due to tensile stress relaxation, resulting in a lower defect density of 7.93 x 10(9) cm(-3) and a remarkable uniformity over a large area. As a result, the co-planar X-ray detectors based on these high-quality SCs exhibit a high sensitivity of 1.67 x 10(5) mu C Gy(air)(-1) cm(-2), representing the best performing MAPbBr3-based X-ray detectors reported to date.

Tin (Sn)-based perovskites have made notable advances with external quantum efficiency of over 20%, but still exhibit low electroluminescence brightness insufficient for outdoor displays. Here, it is demonstrated that compact phenethylammonium tin iodide (PEA2SnI4) films with an intact crystal structure can offer high luminance by optimizing the perovskite crystallization rate simultaneously with engineering the grain surface. Ammonium thiocyanate is added to the precursor solution to generate the film with PEA2SnIxSCN4-x and NH4I after spin-coating. Sn2+ and SCN- have a strong interaction that slows crystallization to improve PEA2SnI4 crystal quality. During the subsequent annealing, I- from NH4I replaces SCN- in PEA2SnIxSCN4-x by forming thiourea, which can escape from the film to leave intact PEA2SnI4 crystals. It is found that the optimized PEA2SnI4 emitting layers can provide outstanding film coverage, high crystallinity, low trap state density, and superior photophysical performance. Consequently, an impressive brightness of 8285 cd m-2 for pure red electroluminescence is achieved, the first report of Sn-based perovskite light-emitting diodes that meet outdoor display requirements.

The pressure-induced emission luminogens (PIEgens) opened the door to highly emissive materials. However, the high-pressure phase with excellent optoelectrical properties is difficult to stabilize at ambient conditions, seriously limiting the practical applications. Here, we first lighted up non-emissive zero-dimensional (0D) metal halide (C 25 H 22 P) 2 SnCl 6 via pressure engineering, ultimately yielding the bright emission. Note that the quenched (C 25 H 22 P) 2 SnCl 6 after pressure treatment of 20.0 GPa exhibited very bright blue–white emission. This irreversible photoluminescence (PL) transition was associated with irreversible amorphization by increasing the potential barrier of phase transition through the steric hindrance effect. The increased distortion of inorganic octahedra and the enhanced hydrogen bond interaction within the amorphous (C 25 H 22 P) 2 SnCl 6 after pressure treatment were responsible for the bright emission. Thus, pressure-triggered PL turn-on behavior can serve as a robust optical switchable logic gate from the initially dark state “0” to the bright state “1”. Furthermore, the pressure-treated (C 25 H 22 P) 2 SnCl 6 exhibited an unexpected excitation-dependent emission. The unique characteristic of “PIE” with different colors can be decoded the Morse code encrypted with the pressure-treated (C 25 H 22 P) 2 SnCl 6 and different excitations. The quenched (C 25 H 22 P) 2 SnCl 6 -based phosphor-converted light-emitting diodes (pc-LEDs), X-ray dose rate detection and centimeter-level patterns highlighted great potentials in lighting, display, scintillators, and anti-counterfeiting.

Lead-free organic-inorganic hybrid perovskites are one class of promising optoelectronic materials that have attracted much attention due to their outstanding stability and environmentally friendly nature. However, the intrinsic band gap far from the Shockley-Queisser limit and the inferior electrical properties largely limit their applicability. Here, a considerable band-gap narrowing from 2.43 to 1.64 eV with the compression rate up to 32.5% is achieved via high-pressure engineering in the lead-free hybrid perovskite MA(3)Sb(2)I(9). Meanwhile, the electric transport process changes from the initial interaction of both ions and electrons to only the contribution of electrons upon compression. The alteration in electrical characteristics is ascribed to the vibration limitation of organic ions and the enhanced orbital overlap, resulting from the reduction of the Sb-I bond length through pressure-induced phase transitions. This work not only systematically investigates the correlation between the structural and optoelectronic properties of MA(3)Sb(2)I(9) but also provides a potential pathway for optimizing electrical properties in lead-free hybrid perovskites.

Metal halide perovskite single crystals (SCs) emerge as a promising candidate for ionizing radiation detection. The realization of top-performing radiation detectors typically relies on careful crystal selection from broad candidate groups, as residual strain remains unavoidable during the SC growth process, which often leads to the formation of ferroelastic domains with varied orientations. Here, we introduce an in-line tempering strategy to alleviate microstrain and homogenize the domain orientation across methylammonium lead iodide (MAPbI 3 ) perovskite SCs. The progressive strain relief during the phase transition in situ, demonstrated by the removal of ferroelastic domain walls, substantially enhances the crystallinity and the optoelectronic properties of the MAPbI 3 SCs. As a result, the gamma-ray energy spectrum detector leveraging these strain-relaxed SCs achieves an energy resolution of 7.2% at 59.5 keV for a 241 Am gamma-ray source, and the 25-pixel device performs highly uniformly with concentrated current distribution, which paves the way for its implementation in high-resolution radiation spectroscopy.

Exploration of pressure-resistant materials largely facilitates their operation under extreme conditions where a stable structure and properties are highly desirable. However, under extreme conditions, such as a high pressure over 30.0 GPa, fluorescence quenching generally occurs in most materials. Herein, pressure-induced emission enhancement (PIEE) by a factor of 4.2 is found in Ga2O3 nanocrystals (NCs), a fourth-generation ultrawide bandgap semiconductor. This is mainly attributed to pressure optimizing the intrinsic lattice defects of the Ga2O3 nanocrystals, which was further confirmed by first-principles calculations. Note that the bright blue emission could be stabilized even up to a high pressure of 30.6 GPa, which is of great significance in the essential components of white light. Notably, after releasing the pressure to ambient conditions, the emission of the Ga2O3 nanocrystals can completely recover, even after undergoing multiple repeated pressurizations. In addition to stable optical properties, synchrotron radiation shows that the Ga2O3 nanocrystals remain in the cubic structure described by space group Fd3m upon compression, demonstrating the structural stability of the Ga2O3 nanocrystals under high pressure. This study pays the way for the application of oxide nanomaterials in pressure anti-counterfeiting and pressure information memory devices.

Despite light-emitting diodes (LEDs) based on quasi-two-dimensional (Q-2D) perovskites being inexpensive and exhibiting high performance, defects still limit the improvement of electroluminescence efficiency and stability by causing nonradiative recombination. Here, an organic molecule, 1-(o-tolyl) biguanide, is used to simultaneously inhibit and passivate defects of Q-2D perovskites via in situ synchronous crystallization. This molecule not only prevents surface bromine vacancies from forming through hydrogen bonding with the bromine of intermediaries but also passivates surface defects through its interaction with uncoordinated Pb. Via combination of defect inhibition and passivation, the trap density of Q-2D perovskite films can be significantly reduced, and the emission efficiency of the film can be improved. Consequently, the corresponding LED shows an external quantum efficiency of 24.3%, and its operational stability has been increased nearly 15 times.

Radiation detectors based on metal halide perovskite (MHP) single crystals (SCs) have exhibited exceptional sensitivity, low detection limit, and remarkable energy resolution. However, the operational stability issue still dramatically impedes their commercialization due to degradation induced by high-energy irradiation and large bias. Here, we propose an innovative infrared healing strategy to restore the devices that have undergone severe damage from both long-term biasing and X-ray irradiation. Compared to the slow and inefficient intrinsic self-healing process of MHPs, the infrared healing method demonstrates the capacity to achieve rapid recovery of the detection performance of the degraded devices within just 1 h. We reveal that the healing mechanism is mainly related to the reduction of the ion-migration activation energy in MHP SCs under infrared illumination, which promotes the back diffusion of the displaced ions to their original lattice positions and remedies defects. Finally, the healing effect is further confirmed through the gamma-ray spectroscopy acquisition with degraded MHP SCs, whose energy resolution at 59.5 keV of 241Am source is improved from 36% to 12% following infrared illumination. These results present infrared healing as a simple and economic method to extend the service life of MHP SC-based detectors.

Pseudohalide doping promoting luminescence properties of lead-free CsMnBr3-based crystals.

The inherent dynamic behavior observed in 2D-3D interfaces in perovskite solar cells (PSC), driven by ion diffusion and migration, poses a significant challenge in establishing a stable passivation and barrier interface that can fulfill the device's complete lifecycle requirements. In this work, we construct large sterically hindered one-dimensional (1D) perovskite crystals integrated with the perovskite surface and observed their evolution during accelerated aging for the first time. The results show that this strong interfacial bonding not only effectively passivates surface defects but also prevents interface reconstruction due to migration, even under elevated temperatures. Moreover, it serving as an effective barrier can significantly suppress the interdiffusion between the copper electrode and the perovskite layer. Resultantly, our approach attained a remarkable effi-ciency of 23.3% via a scalable coating process in FA0.3MA0.7PbI3 PSC device. Notably, these devices exhibited significantly enhanced operational stability (T95 approximate to 1200 h, 55 +/- 5 degrees C) and thermal stability (T90 approximate to 700 h, 85 degrees C).

PbS quantum dot (QD) solar cells harvest near-infrared solar radiation. Their conventional hole transport layer has limited hole collection efficiency due to energy level mismatch and poor film quality. Here, how to resolve these two issues by using Ag-doped PbS QDs are demonstrated. On the one hand, Ag doping relieves the compressive stress during layer deposition and thus improves film compactness and homogeneity to suppress leakage currents. On the other hand, Ag doping increases hole concentration, which aligns energy levels and increases hole mobility to boost hole collection. Increased hole concentration also broadens the depletion region of the active layer, decreasing interface charge accumulation and promoting carrier extraction efficiency. A champion power conversion efficiency of 12.42% is achieved by optimizing the hole transport layer in PbS QD solar cells, compared to 9.38% for control devices. Doping can be combined with compressive strain relief to optimize carrier concentration and energy levels in QDs, and even introduce other novel phenomena such as improved film quality.

Recent advances in luminescent materials have highlighted zero-dimensional (0D) hybrid metal halides as highly efficient candidates. Notably, In3+-based organic-inorganic metal halides (OIMHs) are increasingly recognized as promising materials for solid-state light emission. However, the relatively low light yields of these materials significantly limit their application in advanced optoelectronic devices. In this study, we designed a novel 0D hybrid indium halide, (C13H14N3)3InBr6, where C13H14N3 represents 1,3-diphenylguanidine. This compound features a structure in which the halogen anionic polyhedron is completely isolated by large guanidine cations and is regularly arranged at considerable distances on these cations, thus forming an almost ideal host-guest structure. Impressively, the 0D indium halide exhibits intrinsic broadband yellow-orange light emission, achieving a photoluminescence quantum yield (PLQY) of 86.12%, which is the highest PLQY ever reported for In-based OIMHs. Additionally, we successfully fabricated white-light-emitting diodes (WLEDs) using (C13H14N3)3InBr6 as a yellow phosphor, thereby demonstrating the potential of novel guanidine-based indium halides in solid-state lighting applications. Recent advances in luminescent materials have highlighted zero-dimensional (0D) hybrid metal halides as highly efficient candidates.

Self-trapped exciton (STE) luminescence, typically associated with structural deformation of excited states, has attracted significant attention in metal halide materials recently. However, the mechanism of multiexciton STE emissions in certain metal halide crystals remains largely unexplored. This study investigates dual luminescence emissions in HCOO- doped Cs3Cu2I5 single crystals using transient and steady-state spectroscopy. The dual emissions are attributed to intrinsic STE luminescence originating from the host lattice and extrinsic STE luminescence induced by external dopants, respectively, each of which can be triggered independently at distinct energy levels. Theoretical calculations reveal that multiexciton emission originates from structural distortion of the host and dopant STEs within the 0D lattice in their respective excited states. By meticulously tuning the excitation wavelength and selectively exciting different STEs, the dynamic alteration of color change in Cs3Cu2I5:HCOO- crystals is demonstrated. Ultimately, owing to an extraordinarily high photoluminescence quantum yield (99.01%) and a diminished degree of self-absorption in Cs3Cu2I5:HCOO- crystals, they exhibit remarkable X-ray scintillation characteristics with light yield being improved by 5.4 times as compared to that of pristine Cs3Cu2I5 crystals, opening up exciting avenues for achieving low-dose X-ray detection and imaging.

Three-dimensional (3D) cationic lead halide hybrids constructed by organic ions and inorganic networks via coordination bonds are a promising material for solid-state lighting due to their exceptional environmental stability and broad-spectrum emission. Nevertheless, their fluorescence properties are hindered by the limited lattice distortion from extensive connectivity within the inorganic network. Here, a dramatic 100-fold enhancement of self-trapped exciton (STE) emission is achieved in 3D hybrid material [Pb2Br2][O2C(CH2)4CO2] via pressure-triggered phase transition. Notably, pressure-treated material exhibits a 110 nm redshift with 1.5-fold enhancement compared to the initial state after pressure was completely released. The irreversible structural phase transition intensifies the [PbBr3O3] octahedral distortion, which is highly responsible for the optimization of quenched emission. These findings present a promising strategy for improving the optical properties of 3D halide hybrids with relatively high stability and thus facilitate their practical applications by pressure-driven phase transition engineering.

There exist some perovskites materials with no photoluminescence (PL), which will greatly limit the practical applications in photodetection, display and lighting. Here, we achieve an exotic pressure-induced emission (PIE) at a mild pressure of 0.8 GPa from initially non-emissive 2D all-inorganic perovskite Cs3Sb2Br9 quantum dots, when the sample was subjected to external pressure. With the increase of pressure, the PL intensity gradually increases and the emission color transforms from red to green. Combined with subsequent experiments and computations, thus PIE behavior and piezochromism result from the SbBr6 octahedral distortion, accompanied by a structural phase transition from trigonal to monoclinic under pressure. Our work provides a robust strategy to boost the emission efficiency and to construct multi-functional PIE materials with piezochromism in environmentally friendly perovskites, thus facilitating the diverse applications in futural practices.

Developing effective strategy to passivate surface defects in quantum dots (QDs) is critical to achieving high-efficiency and long-life perovskite light-emitting diodes (LEDs). Here, the supramolecular interaction underpinning of organic-inorganic components is exploited and a facile method is proposed to generate multiple-hydrogen-bonded supramolecular-perovskite crystal structures on QD surfaces by introducing O-Tolylbiguanide (O-Tg) during QD synthesis, enabling bright, conductive, and water-resistant CsPbI3 QDs. Compared with commonly used oleic acid and oleylamine ligands, the biguanide functional group in O-Tg not only forms multiple hydrogen bond interactions with lead halide octahedra passivating both bridging- and terminal-halogen ion defects, but also compatibly occupies the A-site position stabilizing the crystal structure simultaneously. With fewer nonradiative defects and introduced hydrophobic benzene rings preventing eroding of polar molecules, CsPbI3 QDs exhibit remarkable photoluminescence quantum yields of 96%, and their film can be submerged in water for 30 h without degrading. The corresponding LEDs display a high external quantum efficiency (21.2%) and offer superior operational stability with a lifetime (T-90) of 25 h at a constant current density as high as 50 mA cm(-2).