【摘要】 金属卤化物钙钛矿凭借其卓越的光电特性,在光电子器件领域显示出独特的战略价值,其中,铅基体系作为典型代表,在太阳能电池、发光二极管及半导体激光技术方向实现了突破性进展。然而,铅的高毒性及其在环境中可能造成的重金属污染,严重阻碍了其广泛应用和产业化进程。非铅金属卤化物钙钛矿作为绿色环保的替代体系,可以通过等价或异价离子替换铅元素的策略,实现带隙可调、高载流子迁移率及宽光谱响应等性能,成为新兴的研究热点。特别是在激光领域,非铅金属卤化物钙钛矿在低阈值激射、波长可调谐性及新型光学反馈机制方面取得了较大进展。本文围绕非铅金属卤化物钙钛矿的晶体结构和发光机理展开综述,系统分析铅替代元素对能带结构与发光性能的调控作用,以及自陷态激子发光在提升光致发光量子产率上的潜在优势,最后总结了近年来其在激光器件中取得的重要成果,旨在为无铅基钙钛矿高效激光技术的发展提供理论支撑与参考。更多还原

【Abstract】 Significance Metal halide perovskites（MHPs） exhibit high absorption,tunable bandgap,and high carrier mobility,making them promising for next-generation photovoltaics,light-emitting diodes（LEDs）,and coherent light sources.However,the toxicity of lead with persistent environmental effects severely limits commercial viability and sustainability.Recently lead-free metal halide perovskites（LFMHPs） have attracted growing attention as environmentally friendly alternatives with compelling opto-electronic characteristics.In addition to ecological benefits,LFMHPs exhibit diverse structural and photophysical properties,which provide new approaches in coherent light generation.Their compatibility with solution-based synthesis,soft lattice characteristics,and defect tolerance extend applications for miniaturized,tunable,and flexible photonic devices,particularly in the field of semiconductor lasers.With the growth of global demand for lead-free compatible technology,LFMHPs stand as a promising platform to meet the dual goals of performance and sustainability in photonic applications.Progress The attempt to develop LFMHPs has mainly followed two substitution strategies:isovalent cation substitution(e.g.,Sn²⁺,Ge²⁺) and heterovalent cation substitution(e.g.,Ag⁺/Bi³⁺ or Cu⁺/Sb³⁺ combinations).These approaches derive a series of perovskite structures,ranging from traditional 3D ABX₃ lattices to low-dimensional and double perovskite configurations such as A₂B（Ⅰ）B（Ⅲ）X₆ and A₃B（Ⅲ）₂X₉（Fig.3）.These diverse structural motifs not only influence band structure and stability,but also govern exciton dynamics and emission mechanisms.Among isovalent systems,Sn-based perovskites（e.g.,ASnX₃） show potentiality due to their direct band gaps,tunable PL spectrum from visible to near-infrared regions,and high carrier mobility（Fig.4）.Their lasing performance has been demonstrated in various cavities,for instance,（PEA）₂SnI₄ and CsSnBr₃ single crystals have exhibited lowthreshold lasing and high Q-factor.To mitigate issues such as Sn²⁺oxidation and lattice degradation,recent studies have introduced molecular additives and low-dimensional structures that enhance photo stability and emission performance.The substitution of Pb²⁺ions with heterovalent cations introduces disparities in electronic configuration and oxidation state,which profoundly affect the crystal structure,bandgap,and electronic state distribution of the host lattice.In such systems,excitons are strongly localized by both lattice defects and the presence of heterovalent dopants,often leading to the formation of self-trapped excitons（STEs）.STEs arise when excitons become localized due to strong exciton-phonon coupling,resulting in emission energies significantly lower than the material’ s bandgap.The localization typically manifests as a pronounced Stokes shift,increased exciton binding energy,and extended photoluminescence lifetimes.These characteristics can be effectively investigated through temperature-dependent photoluminescence spectroscopy and transient absorption measurements.Materials such as Cs₂AgNaInCl₆ and Cs₃Cu₂X₅ exhibit broad emission spectra,large Stokes shifts,and high PLQYs（photoluminescence quantum yields） up to 80%（Fig.5）.The photophysical characteristics of LFMHPs render them suitable as gain media for various laser configurations.A wide variety of laser architectures such as whispering gallery mode（WGM）,Fabry-Pérot（FP）,distributed feedback（DFB）,vertical cavity surface emitting lasers（VCSELs）,and random lasers（RL） have been realized using different LFMHP compositions and nanostructures.In2023,Lin and colleagues developed Cs₃Cu₂I₅ thin films via dual-source co-evaporation and integrated them within a vertical cavity formed by two distributed Bragg reflectors（DBRs）,achieving lasing at 440 nm under femtosecond excitation with a threshold of1.12 μJ/cm².By incorporating an additional gain layer and DBR,dual-wavelength lasing at 458.8 nm and 505.6 nm was realized with a threshold of 5.62 μJ/cm².Concurrently,Petrozza s group patterned dielectric gratings using electron-beam lithography and reactive ion etching,followed by spin-coating a～110 nm-thick PEA₂SnI₄ perovskite layer.At 77 K,the resulting DFB laser demonstrated a narrow linewidth（0.9 nm） and low threshold energy density（19 μJ/cm²）,highlighting the potential of LFMHPs in high-coherence light generation.Alternative cavity strategies include bio-inspired platforms:in 2016,Sum and co-workers employed natural photonic crystal structures derived from butterfly wings as optical resonators.Using CsSnI₃ films with 20% SnF₂ additive to suppress Sn²⁺oxidation,they achieved single-mode near-infrared lasing with a threshold energy density of～15 μJ/cm²,demonstrating compatibility with non-planar and flexible substrates.Further extending this approach,Lee’s team synthesized CsSnI3 quantum dots and embedded them in a cholesteric liquid crystal（CLC） resonator to construct a tunable DFB laser.The device exhibited ultralow threshold energy（0.15 μJ per pulse）,narrow linewidth（0.20 nm）,and wavelength tunability from 582 to 606 nm.Impressively,it retained～87% of its initial efficiency after six months of storage under ambient temperature and high humidity,underscoring the environmental resilience of optimized LFMHP-based laser architectures（Table 1）.Conclusions & Prospects LFMHPs have progressed from eco-friendly alternatives to a distinct class of photonic semiconductors,characterized by exceptional compositional versatility and tunable optoelectronic properties.Their demonstrated compatibility with multiple lasing architectures combined with low thresholds,wide spectral tunability,and defect-tolerant nature,position them as strong candidates for future coherent light sources.Nonetheless,achieving practical deployment demands further progress in enhancing environmental and operational stability,mitigating defect-induced nonradiative losses,and deepening the understanding of exciton-lattice coupling.Advances in material design,surface passivation,microcavity integration,and theoretical modeling will be essential to overcome current limitations.LFMHP-based lasers hold strong prospects for enabling high-performance and sustainable photonic te chnologies.更多还原