​Enhanced bulk photovoltaics in polar 2D hybrid perovskite via pressure-strengthened organic-inorganic interactions – Dr. Xujie Lü

The bulk photovoltaic effect (BPVE) has attracted increasing attention as a promising paradigm for next-generation photovoltaic and self-powered optoelectronic devices. Thus far, the BPVE performance of two-dimensional (2D) organic-inorganic hybrid perovskite (OIHP) ferroelectrics remains far from practical requirements. This challenge is largely due to the lack of a well-established structure-property relationship connecting organic-inorganic interactions, structural polarization, and BPVE output. A research team led by Dr. Xujie Lü from the Center for High Pressure Science and Technology Advanced Research (HPSTAR), in collaboration with Dr. Junhua Luo and Dr. Zhihua Sun from the Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, report enhanced bulk photovoltaics in polar 2D hybrid perovskite via pressure-strengthened organic-inorganicinteractions. The team demonstrated that stronger hydrogen bonding under pressure can simultaneously increase the photocurrent and photovoltage of a polar two-dimensional hybrid perovskite. At 1.5 GPa under 405 nm illumination, the bulk photovoltaic efficiency of 2D BDA(EA)₂Pb₃Br₁₀ reached 0.18%, approximately 530 times the initial value. The work, entitled “Enhanced Bulk Photovoltaics in Polar 2D Hybrid Perovskite via Pressure-Strengthened Organic-Inorganic Interactions”, was recently published in Advanced Materials.

The bulk photovoltaic effect allows non-centrosymmetric crystals to generate electrical output without a p-n junction. Polar organic-inorganic hybrid perovskites offer a versatile platform for studying this effect, but the connection between their molecular interactions, polarization and photovoltaic output has remained insufficiently understood. Pressure provides a way to follow these changes continuously in the same material without changing its chemical composition.

The researchers investigated the Dion-Jacobson perovskite BDA(EA)₂Pb₃Br₁₀, where BDA is 1,4-butanediammonium and EA is ethylammonium. Hydrogen bonds at both ends of the BDA²⁺ cations bridge adjacent inorganic layers, coupling molecular orientation to the geometry of the PbBr₆ framework. In a two-electrode device inside a diamond anvil cell, the short-circuit current increased from 9.6 pA to 0.44 nA at 1.5 GPa, while the open-circuit voltage rose from 0.06 V to 0.69 V. These changes correspond to factors of 45.8 and 11.5, respectively. The measured efficiency exceeded those of the previously reported polar 2D hybrid perovskites compared in the paper.

In situ high-pressure powder and single-crystal X-ray diffraction, together with infrared and Raman spectroscopy, traced the structural origin of this enhancement. Compression shortened and reorganized the N-H···Br hydrogen-bond network, promoted orientational ordering of the organic cations, and increased Pb off-centering and PbBr₆ octahedral distortion. These cooperative changes strengthen structural polarization, promoting the separation and transport of photogenerated carriers and increasing both current and voltage.

Pressure also stabilized the ferroelectric state: temperature-dependent second-harmonic generation measurements showed that the Curie temperature rose from 373 K at ambient pressure to 433 K at 1.9 GPa. The photovoltaic response reached its maximum at 1.5 GPa and declined at higher pressures, as a structural transition near 1.8 GPa disrupted organic-cation orientational order. The response was largely reversible on decompression.

The findings identify hydrogen-bond-mediated coupling between molecular orientation and inorganic distortion as a route to optimizing bulk photovoltaics. They also provide a structural basis for future ambient-pressure materials design through tailored organic-inorganic interactions.

Caption: Pressure strengthens organic-inorganic interactions, coupling molecular ordering and octahedral distortion to enhance polarization and bulk photovoltaic output.

Publication：Enhanced Bulk Photovoltaics in Polar 2D Hybrid Perovskite via Pressure-Strengthened Organic-Inorganic Interactions. Advanced Materials, 2026, e75197.

体光伏效应可在无需p-n结的非中心对称材料中产生光生电流和光电压，在新一代光伏和自驱动光电器件等领域受到广泛关注。然而，二维有机-无机杂化钙钛矿铁电体的体光伏性能距离实际应用需求仍有极大差距，其关键原因之一在于有机-无机相互作用、结构极化与体光伏输出之间的微观联系尚缺乏清晰认识。针对这一问题，北京高压科学研究中心（HPSTAR）吕旭杰团队联合中国科学院福建物质结构研究所罗军华、孙志华团队等，以Dion-Jacobson型二维有机-无机杂化钙钛矿BDA(EA)₂Pb₃Br₁₀ 为研究对象，通过压力调控实现了体光伏效应的显著增强，揭示了氢键增强驱动有机阳离子有序和无机八面体畸变的协同机制。北京高压科学研究中心的博士生房诗玉，卜克军博士为该文章共同第一作者。复旦大学、上海前瞻物质科学研究院等单位的研究人员参与了合作。成果发表于《先进材料》（Advanced Materials）。