Chunpeng Song

Poor device reproducibility and insufficient processing robustness hinder organic photovoltaics (OPVs) industrialization, primarily due to poor morphological reproducibility of the active layer. Here, we establish a direct correlation between the morphology evolution pathway and morphological reproducibility. When evolution is governed by solid‐state relaxation, the active layer converges into energetically similar low‐energy metastable ensembles, yielding highly reproducible morphologies. In contrast, rapid quenching traps the active layer in a broad distribution of low‐energy metastable states, leading to poor morphological reproducibility. This principle is validated through two independent approaches: molecular structure design and additive engineering. Chemically, acceptor dimerization (PM6:DY2) shifts evolution from quenching‐ to relaxation‐dominated, reducing the coefficient of variation ( CV , a reproducibility measure) from 2.14% to 1.19% and increasing the performance figure of merit ( P‐FOM , a robustness measure) from 0.925 to 0.944. Physically, replacing the additive 1,2,4‐TCB with 1,3,5‐TIB delays the evolution of PM6:L8‐BO to the relaxation stage, achieving 19.59% PCE while achieving a record‐low CV of 0.86% (reduced from 1.55%) and increasing P‐FOM from 0.935 to 0.955. These findings establish a general principle: solid‐state relaxation‐dominated evolution leads to morphological convergence and device performance consistency, providing a theoretical basis for rational design toward high reproducibility and robustness in OPVs.

Organic solar cells (OSCs) have emerged as a promising next‐generation photovoltaic technology owing to their unique advantages, including flexibility, light weight, and solution processability. Although the power conversion efficiency (PCE) of single‐junction devices has exceeded 21%, insufficient thermal stability remains a major bottleneck to commercialization. This review systematically summarizes three major mechanisms responsible for thermally induced degradation in photovoltaic devices: insufficient intrinsic thermal stability of the constituent materials, thermally induced morphological evolution of the active layer, and interfacial aging. On this basis, representative advances in improving thermal stability are reviewed from three perspectives: intrinsic material design, morphology‐locking strategies, and interface engineering. Finally, the challenges associated with simultaneously optimizing efficiency and thermal stability are discussed, highlighting the importance of coordinated design across the entire device architecture for advancing organic photovoltaics toward practical applications.

Strong interactions between large dipole moment additives and host materials have been widely used to modulate molecular packing in organic solar cells (OSCs), while most studies focuses on dipole moment magnitude instead of the polarization properties orientation. Here, we challenge this oversimplified view by demonstrating that the polarization properties orientation—determined by both dipole orientation and polarizability anisotropy, rather than dipole magnitude alone – is the important factor. To quantify this, we introduce the “polarization properties orientation coupling degree” ( P ), which quantifies the matching of dipole orientation and polarizability distribution between additives and acceptors. Employing 1,4‐diiodobenzene (DIB) and 1,3,5‐triiodobenzene (TIB) as additives in the PM6:Y6 system with identical dipole moment magnitude but different orientation, we find that TIB exhibits a much higher p value (1.455 vs. 0.191), resulting in stronger intermolecular interactions. Consequently, TIB induces the formation of S‐type and S′‐type dimers of Y6, which optimizes exciton and charge transport behavior, boosting the performance from 17.53% to 18.08%. Furthermore, this principle is validated in high‐performance systems of PM6:L8‐BO (19.33%) and PM6:BTP‐eC9 (19.23%), and shows significant advantages in large‐area fabrication and reproducibility. This study highlights the significant role of polarization properties orientation, offering rational design strategy for high‐performance OSCs.

The ambient laser shock annealing (LSA) strategy enables crystallization kinetics optimization in quasi-two-dimensional (Q-2D) perovskites, yielding photovoltaic devices with high efficiency and stability. This process initiates ultrafast crystallization through the formation of a stable PbI2 intermediate phase, driven by synergistic thermal and shock-wave effects that operate on the timescale of the laser pulse and deliver a peak pressure of 8.91 GPa. The consequent uniform stress field (attenuation below 5% over 500 nm) facilitates the development of a refined microstructure in the Q-2D perovskite, manifested as grain growth, texturing, and dipole moment reduction. Such a microstructure supports a power conversion efficiency (PCE) of 20.41%, achieved by suppressing non-radiative recombination and optimizing polaron dynamics via aligned organic cations. Furthermore, reinforced inorganic-organic interactions coupled with an elevated Young's modulus of 28.38 GPa underpin the substantially improved long-term stability. These coordinated improvements demonstrate that LSA is an effective strategy grounded in well-defined mechanisms for advancing perovskite device performance.

Mixed-halide perovskites are susceptible to ion migration due to their high lattice flexibility, resulting in a decrease in device efficiency and the degradation of device stability. In this work, by utilizing the unique pulse characteristics and thermal effects of the nanosecond laser shock annealing (LSA) technique, we can effectively inhibit ionic migration in mixed-halide perovskites, which in turn ameliorates the optoelectronic properties of perovskites. The results show that, compared with traditional thermal annealing (TA), the perovskite films treated by LSA exhibit a more uniform ionic distribution, eliminating the nonphotoactive δ-phase caused by ionic segregation. The reduction in ionic migration is attributed to the enhanced interaction among the inter-ionic forces in the inorganic framework and the optimization of crystallization kinetics in a mixed-halide perovskite, resulting from the ultrafast shock pressure in the range of 0.95-1.64 GPa and the rapid heating/cooling thermal effects of LSA. Furthermore, the perovskite fabricated by LSA significantly reduces the defect density, mitigating defect-driven ionic migration. Therefore, the photophysical processes of perovskites were optimized, which extended the carrier lifetime and enhanced the carrier mobility. In conclusion, the LSA technique provides an efficient approach to addressing the problem of ion migration in mixed-halide perovskites by modulation of the crystal structure and ionic interactions.

This review comprehensively summarizes the recent advances in OSC reproducibility of organic solar cells from material synthesis, film preparation, and interfacial & electrode, which would provide significant insights into large-scale fabrication.

Surface‐enhanced Raman scattering (SERS) is a frontier technology for high‐sensitivity analysis of molecules and chemical substances, and a useful tool in the sensing field relying on fingerprint recognition ability, high sensitivity, multiple detection, biocompatibility, and so forth. SERS substrates have been well concerned attributed to their ability to enhance Raman signals, which makes them useful in various applications, including sensing and detection. At the same time, flexible SERS substrates enable sample loads to meet requirements and, therefore, have high sensitivity for Raman detection, but the detection capacity is still limited. In this paper, the basic principle and method of SERS were reviewed, and some new trends of micro‐ and nanostructured SERS substrates were reviewed from the aspects of material, matrix type, preparation, and application.

Additives have found widespread application in perovskite optoelectronic devices, playing a crucial role in enhancing the performance and stability of these devices by optimizing the crystallization kinetics of the perovskite. However, the nonuniform distribution of additives in perovskite films caused by the bottom-up volatilization of low-boiling-point additives during traditional thermal annealing is a challenging issue that needs to be solved. In this work, we propose a strategy that integrates laser processing technology with the dithieno[3,2-b:2',3'-d]thiophene (DTT) additive process, which enables it to reduce defects by interacting with the octahedral inorganic framework of perovskite. Initially, the micro-nanostructure of the perovskite film is enhanced by the fast crystallization induced by high-energy pulsed laser irradiation, which in turn modulates the evaporation of the solution to regulate the distribution of DTT. Concurrently, the shock pressure generated by the pulsed laser further restricts the accumulation of DTT and promotes its uniform distribution within the perovskite film. As a result, by optimizing the crystallization kinetics of perovskite through pulsed laser and DTT, the crystal structure and electronic structure optimization of perovskite film lead to a reduction in defect density. The optimization of carrier dynamics further enhances the performance of the device with an excellent T₈₀ stability of about 2400 h. This approach will provide a technical framework and theoretical basis for controlling the perovskite crystal growth and defect passivation to achieve large-scale commercial applications.

Organic solar cells (OSCs) are developing as a crucial technology for sustainable energy, attaining power conversion efficiencies (PCEs) of over 20%. The morphology of the active layer is essential in influencing PCE, but its exact manipulation is difficult because of the complex interactions between donor and acceptor molecules. The molecular weight ( M _w ) of polymers is a crucial parameter that significantly affects morphological development, including domain size, purity, crystallinity, and molecular orientation. Here the trade‐offs of M _w regulation are examined, emphasizing that high‐ M _w polymers improve stability and crystallinity but may hinder phase separation. In contrast, low‐ M _w polymers promote finer phase separation at the cost of mechanical integrity. Moreover, current achievements are synthesized to clarify methodologies for optimizing M _w to achieve balanced morphological features, to enhance active layer design, and maximize the potential of OSCs. These insights facilitate the resolution of existing difficulties and promote the advancements of OSCs toward useful and sustainable applications.

Surface‐enhanced Raman scattering (SERS) is a frontier technology for high‐sensitivity analysis of molecules and chemical substances, and a useful tool in the sensing field relying on fingerprint recognition ability, high sensitivity, multiple detection, biocompatibility, and so forth. SERS substrates have been well concerned attributed to their ability to enhance Raman signals, which makes them useful in various applications, including sensing and detection. At the same time, flexible SERS substrates enable sample loads to meet requirements and, therefore, have high sensitivity for Raman detection, but the detection capacity is still limited. In this paper, the basic principle and method of SERS were reviewed, and some new trends of micro‐ and nanostructured SERS substrates were reviewed from the aspects of material, matrix type, preparation, and application.