Small
·
2025
·Vol. 21
·期 46
·2500761
·
IF 12.1
Yalong Shen,Yuan Zhu,Jia Jia,Yanni Bi,Yinqian Hu,Jun Huang,Hu Sun,Zaizhi Yang,Xinxing Li,Yue Wang,Jiawei Chen
Halide perovskites hold significant promise for photodetection applications due to their high carrier mobility, long carrier diffusion lengths, and solution-processing compatibility. However, lead toxicity in lead-based perovskites and the indirect bandgap nature of lead-free perovskites have limited their practical application. In this work, a solution-based method is used to synthesize lead-free Bi-based Cs 3 Bi 2 I 9 perovskite nanoplatelets (NPs) in situ with large lateral sizes, high crystallinity, and smooth surface. Theoretical calculation results and optical properties indicate that the reduced dimensionality enables Cs 3 Bi 2 I 9 NP with a direct-indirect bandgap nature, while excitonic absorption dominates the absorption edge and obscures the electronic bandgap. Benefiting from this, as-fabricated vertical-structure photodetector (PD) based on Cs 3 Bi 2 I 9 NPs demonstrates outstanding photodetection performance with a high responsivity of 47.4 mA W −1 and a fast rise/fall time of 0.86/2.21 ms. Besides, the device exhibits excellent long-term stability, retaining 95% of its initial current density after three months of exposure to the air. This work provides valuable design guidelines and insights into developing lead-free perovskites for high-performance PD.
研究领域:
光电子学
·
材料科学
·
纳米技术
·
半导体器件
·
光电探测
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高影响因子
PHYSICA B-CONDENSED MATTER
·
2026
·
IF 3.2
Jiayi Shen,Long Li,Chengwu Yang,Wei-Hsiang Chen,Lu Chen,Jinxin Bian,Fan Wu
Thermal annealing is standard for perovskite fabrication; however, for lead-free Cs 3 Bi 2 I 9 , it triggers a fatal trade-off between crystallinity and surface stoichiometry. We reveal that thermal stress induces severe iodine volatilization, generating deep-level vacancy traps that pin the Fermi level and reverse surface band bending, thereby sabotaging electronic properties. To decouple crystallization from defect generation, we introduce an annealing-free, room-temperature crystallization paradigm, exploiting the material's unique 0D molecular nature to drive spontaneous self-assembly. Consequently, non-annealed films maintain superior stoichiometry, delivering a >300% enhancement in charge separation efficiency and significantly prolonged carrier lifetimes. Kinetic modeling confirms that annealing introduces a rapid (∼75 ns) surface decay pathway while leaving the bulk carrier lifetime (∼150 μs) largely intact, identifying the surface as the exclusive locus of defect-induced degradation. These findings establish a 'less-is-more' methodology for optimizing volatile optoelectronic materials, shifting the processing focus from grain size optimization to stoichiometric integrity.
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Journal of Physical Chemistry C
·
2022
·
IF 4.177
Luji Li,Gang Ye,Tianyuan Luo,Xiayan Chen,Gaojie Zhang,Hao Wu,Li Yang,Wenfeng Zhang,Haixin Chang
The detection of broadband spectroscopy is a huge challenge for modern optoelectronics, especially for extremely high- or low-energy photons. For metal halide perovskites significant progress has been made in high-energy photons such as X-rays, but there is little exploration of the perovskites in the high-performance detection of low-energy photons, especially mid- or far-infrared photons. Most infrared photodetectors suffer large dark currents, and perovskite photodetectors’ performances are significantly limited by ion migration. Here, a facile solution evaporation method is developed to grow a centimeter-scale zero-dimensional (0D), lead-free perovskite Cs3Bi2I9 single crystal for high-performance mid-infrared photodetectors with ultralow dark current drifts. The 0D Cs3Bi2I9 perovskite single crystal (PSC) photodetector shows an ultralow dark current drift (1.67 × 10–17 A cm–2 V–1 s–1, 9 orders of magnitude smaller than that of MAPbI3) and ultralow power consumption (smaller than 1 pA at 1 V bias) for greatly inhibited ion migration. The photodetector achieves effective photodetection from the ultraviolet to the mid-infrared (from 343 to 4000 nm) at room temperature based on the photoelectric and photobolometric effects with the best responsivity of 3.15 mA/W and detectivity of 8.7 × 108 jones at the wavelength of 343 nm at 0.033 mW/cm2. This work opens a door for low-dimensional perovskite-based mid-infrared detectors and provides a new path for the development of infrared perovskite photonics.
研究领域:
光电子学
·
材料科学
·
钙钛矿光子学
·
红外探测
·
半导体器件
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DOI
高影响因子
ACS Applied Materials & Interfaces
·
2026
·Vol. 18
·期 33
·45407-45419
·
IF 7.8
Liu Hongyang,Chen Jin,Zhan Enyu,Sun Yu,Yang Jing,Zhang Canyun,Kong Jinfang,Li Lan,Wang Fengchao
The evolution toward a genuinely intelligent Internet of Things envisions future optical wireless networks anchored by extensive terminal nodes to facilitate pervasive sensing and communication. This vision places unprecedented demands on the underlying hardware, particularly in terms of scalability, energy efficiency, and cost-effectiveness. As the pivotal component within these terminal nodes, the system integrability and manufacturing cost of photodetectors are of critical importance. Accordingly, a Cs 3 Bi 2 I 9 /SnO 2 heterojunction photodetector was developed entirely via an ambient-air, solution-based technique. The device exhibits a spectral response from 365 to 520 nm and, at zero external bias, achieves a peak responsivity of 11.7 mA/W, a specific detectivity of 2.9 × 10 11 Jones, and a rapid response time of 33/52 μs. It retained its key performance metrics after more than 2160 h of storage in ambient air, demonstrating excellent long-term environmental stability. Under operational testing, only marginal performance degradation was observed after continuous illumination for over 4000 s, confirming its reliability for sustained use. As the core receiving device, it faithfully converted ASCII-encoded optical inputs into high-fidelity electrical signals, enabling accurate text recovery across three independent communication bands. This study provides a viable strategy for developing functional and sustainable photodetectors for open Internet of Things systems.
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ACS Applied Nano Materials
·
2026
·Vol. 9
·期 29
·13832-13841
·
IF 5.8
Li Guihua,Tang Lingzhi,Wang Jingjuan,An Shuailing,Sun Mengjuan,Jiao Yinan,Yang Zhigang,Ren Shuxia,Liu Jinxi
A flexible, eco-friendly, and photoelectrically modulated
synaptic
resistive random access memory (ReRAM) device has been developed using
a lead-free nanoscale Cs 3 Bi 2 I 9 Quantum
Dot (QD) graphene oxide (GO) composite film. The Ag/PMMA/Cs 3 Bi 2 I 9 QD/GO/ITO device exhibits a remarkable
ON/OFF ratio exceeding 10 4 under illumination, representing
approximately 200-fold enhancement compared to its performance in
darkness (∼10 2 ). The device demonstrates exceptional
mechanical and environmental stability, withstanding 10,000 bending
cycles (4.6 mm radius) and 72 h of ambient exposure (25 ° C, 35%
RH). Furthermore, when implemented in an artificial neural network
(ANN) for supervised learning, the device enables a recognition accuracy
of 94.3%. We attribute this enhanced performance to a synergistic
mechanism associated with the nanoscale dimension and uniform dispersion
of Cs 3 Bi 2 I 9 QD in the composite.
First, a poly(methyl methacrylate) (PMMA) protective layer effectively
suppresses leakage current, thereby elevating the high-resistance
state (HRS). Second, photogenerated holes within the Cs 3 Bi 2 I 9 QD are efficiently trapped, promoting
the formation of I – vacancies (V I – ). This synergistic effect facilitates the formation
of hybrid Ag/V I – conductive filaments,
reducing both SET voltage (by 47.7%) and low-resistance state (LRS)
resistance under illumination. These findings underscore the pivotal
role of optoelectronic coupling in optimizing resistive switching
behavior, paving the way for sustainable neuromorphic computing systems.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Jiayi Shen,Long Li,Jinxin Bian,Lu Chen,Ninghao Zheng,Xiaoxun Wu,Fan Wu
Surface functionalization with the dye Z907 reconfigures the electronic landscape of lead-free Cs 3 Bi 2 I 9 perovskite photodetectors and triples zero-bias performance. The dye modification layer leaves morphology intact ( R a ≈12 nm) yet passivates traps, as SCLC confirms. Kelvin-probe mapping discloses a 300 mV Fermi-level downshift that aligns the valence band of Cs 3 Bi 2 I 9 with the highest ccupied molecular orbital of P3HT, enabling efficient hole extraction. The Cs 3 Bi 2 I 9 /Z907/P3HT stack delivers a surface photovoltage of 325 mV and cuts rise/decay constants from 496/313–285/286 ms. Transient surface photovoltage traces reveal a polarity reversal, seven-fold surface photovoltage amplification, and a lengthened tail, evidencing redirected carrier flow and suppressed trap-assisted back-transfer. Dynamic intensity-modulated photocurrent spectra display an order-of-magnitude reduction in charge-transfer time and a larger high-frequency phase lead, confirming faster interfacial hole extraction and lower recombination resistance. These dynamics yield a bias-free responsivity and detectivity 2–3 times higher than in bare films, while the device cleanly encodes 8-bit ASCII via binary light pulses, illustrating the promise of molecular interface engineering for energy-autonomous visible-light communication.
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