High-performance Perovskite Photodetectors Research Articles

Machine learning-assisted design of high-performance perovskite photodetectors: a review

Machine learning-assisted design of high-performance perovskite photodetectors: a review

Numerical modelling of lead-free perovskite photodetector with GO as ETM and Cz-N as HTM

Photodetectors (PD) are optoelectronic devices that can convert optical signal into electrical signals via the photoelectric effect. A model of CsSn0.5Ge0.5I3 based nip perovskite photodetector (PePd) with graphene oxide (GO) as electron transport material (ETM) and carbazole unit with naphthalene (Cz-N) is used as hole transport material (HTM) are established. The device configuration was analysed using solar cell capacitance simulator-1 dimensional (SCAPS-1D). The effects of absorber thickness, defect density of CsSn0.5Ge0.5I3, metal work function and operating temperature on device architecture have been investigated. For the incident light between 800-820 nm, a maximum responsivity and detectivity 0.65 A/W and 3.6×1013 Jones are obtained respectively. This simulation results will assist in the future research on high-performance lead-free perovskite photodetectors.

High Performance Perovskite Photodiodes via Molecule-Assisted Interfacial and Bulk Modulations.

Metal halide perovskites have attracted significant attention in photodetection due to their superior photophysical properties and improved stability. However, the performance of their photodiodes is predominantly limited by non-radiative recombination within the perovskite layer or at interfaces. Here, molecular engineering via phenylethylammonium chloride for interfacial modulation and methylenediammonium dichloride for bulk modulation is introduced into vertical perovskite photodiodes to boost the photodetection performance. The responsivity at 635 nm excitation increased from 0.09 to 0.33 AW-1 with interfacial modulation, compared to the original perovskite device, and is further improved to 0.40 AW-1 with the combined effects of interfacial and bulk modulations (i.e., synergistic bimolecular engineering). The optimized photodiodes demonstrated high detectivity of over 1011 Jones, a rapid response time of ≈1 µs, and a linear dynamic range of ≈100 dB. Furthermore, the photocurrent exhibited a U-shaped dependence on temperature ranging from 10 to 300 K, with linearity breaking under strong illumination at low temperatures. These results confirmed that molecular engineering is the promising strategy for achieving high-performance perovskite photodetectors.

High-Performance Broadband Photodetectors Combining Perovskite and Organic Bulk Heterojunction Bifunctional Layers

Perovskite can be used to prepare high-performance photodetectors due to its excellent optical properties. However, the detection range of perovskite photodetectors is mostly limited to the visible light range, restricting their further development and application. In recent years, combining perovskite with organic bulk heterojunctions to prepare photodetectors with broadband detection capability has proven to be an effective strategy. Through this approach, the response spectrum of the photodetector can be flexibly regulated, and organic compounds can improve the perovskite film quality by passivating defects and inhibit the penetration of water molecules in the air, thereby improving the device performance and stability. In this work, we propose and demonstrate the feasibility of combining MAPbI3 perovskite with PTB7-Th:COTIC-4F to prepare high-performance photodetectors with wide spectral response characteristics. With the assistance of an organic bulk heterojunction, the defects of perovskite crystals are effectively passivated, and the detection spectrum of the device is successfully extended to about 1100 nm. As a result, the responsivity achieved is 0.58 A/W, 1.19 A/W, and 1.41 A/W under laser illumination of 532 nm, 808 nm, and 980 nm, with the power density of 5 μW/cm2 at the bias voltage of −0.5 V, respectively, which is one of the best performances among vertical device structures of this type. Moreover, the stability of the final hybrid film has been greatly improved. This work provides a new approach to the preparation of high-performance and broadband perovskite photodetectors.

Exploiting coordination between poly (ethylene glycol) bis (carboxymethyl) ether and SnO2 for high-performance perovskite photodetectors

In perovskite detectors that utilize SnO₂ as an electron transport layer (ETL), the preparation of SnO₂ films using the solution method results in a significant number of defects. Additionally, the presence of nano-aggregates in the aqueous solution of untreated SnO₂ colloids leads to surface unevenness in SnO₂ films prepared using the spin-coating method, which can affect the growth and crystallization of perovskite. Defects and surface unevenness in SnO₂ films affect the performance of perovskite detectors. To further optimize the performance of perovskite detectors, SnO₂ incorporating poly (ethylene glycol) bis (carboxymethyl) ether (PBE) was developed, employing the polymer as a modifier. The results of the study showed that the incorporation of PBE had two effects: 1) the ether oxygen within the PBE forms a coordination bond with SnO₂, thereby reducing oxygen vacancies, and 2) reducing nano-aggregation of SnO₂ colloidal aqueous solutions, obtaining more uniform SnO₂ films, and promoting the growth and crystallization of perovskite. Ultimately, the performance of the optimized device was improved. The external quantum efficiency (EQE) improved from 84.82 % to 89.29 %, the dark current density decreased from 3.27 × 10-⁹ A cm-² to 1.03 × 10-¹⁰ A cm-², the linear dynamic range (LDR) increased from 88.5 to 118.3 dB, and the stability was enhanced. The device maintained 64.9 % of its original efficiency after being stored for 23 days at 25 °C and 20–30 % humidity.

Highly efficient self-powered CH3NH3Pbl3 perovskite photodiode with double-sided poly(methyl methacrylate) passivation layers

Hybrid organohalide perovskites have recently attracted significant attention due to their outstanding photovoltaic (PV) conversion capabilities in optoelectronic devices. Herein, to develop a highly sensitive and self-powered perovskite-based PV photodiode (PVPD), we implement the selective use of poly(methyl methacrylate) (PMMA) as noise-current-reducing passivation layers on both the front and rear sides of a CH3NH3PbI3 (MAPbI3) perovskite light-absorbing layer. It is found that the PMMA layers effectively suppress carrier recombinations at the interfaces, resulting in fairly high power conversion efficiency of 17.6%. Additionally, the double-sided PMMA-passivated MAPbI3 PVPD shows exceptional specific detectivity values (1.0 × 1014 Jones from the dark current and 1.3 × 1012 Jones from the noise current), significantly outperforming conventional MAPbI3 PVPDs without passivation layers. The device also exhibits a very wide linear dynamic response range of ∼139 dB, with rapid rise and decay response times of 57 and 18 μs, respectively. The double-sided PMMA-passivated MAPbI3 PVPD also is shown to be highly durable in terms of its dynamic responses even after a prolonged storage period of 1500 h. These results suggest that advanced interface engineering using double PMMA passivation layers holds great potential for developing high-performance self-powered perovskite photodetectors for a range of optoelectronic applications.

Regulating energy band alignment for high-performance broadband perovskite photodetectors

The excellent detection performance of photodetector is realized by adjusting the energy band arrangement at the interface between perovskite and electrode. The optical response mechanism beyond the band gap limit is explained.

Synergistic nucleation regulation using 4,4',4''-tris(carbazol-9-yl)-triphenylamine and moisture for stably air-processed high-performance perovskite photodetectors.

Perovskite photodetectors (PPDs) offer a promising solution with low cost and high responsivity, addressing the limitations of traditional inorganic photodetectors. However, there is still room for improvement in terms of the dark current and stability of air-processed PPDs. In this study, 4,4',4''-tris(carbazol-9-yl)-triphenylamine (TCTA) was utilized as a nucleation agent to enhance the quality of perovskite films. The synergistic effect of TCTA and moisture promotes rapid nucleation of PbI2-PbCl2, resulting in an increased nucleation rate and the elimination of pinholes in the film. By employing additive engineering, we obtained a PbI2-PbCl2 layer with high coverage, leading to a low density of traps in the corresponding perovskite film. Consequently, the modified PPD exhibits a remarkable reduction in dark current density by over one order of magnitude, reaching 2.4 × 10-10 A cm-2 at -10 mV, along with a large linear dynamic range (LDR) of 183 dB. Furthermore, the resulting PPD demonstrates remarkable stability, retaining 90% of the initial external quantum efficiency (EQE) value even after continuous operation for over 3200 hours. Owing to a fast response time in the nanosecond range, the PPD could convert modulated light signals into electrical signals at a speed of 588 Kbit s-1, highlighting the great potential in the field of optical communication.

Surface Microstructure Engineering in MAPbBr3 Microsheets for Performance-Enhanced Photodetectors.

Metal halide-perovskite-based photodetectors have recently emerged as a class of promising optoelectronic devices in various fields. Meanwhile, nano/microstructuring perovskite-based photodetectors are a facile integration with complementary metal-oxide semiconductors for miniaturized imaging systems. However, there are still challenges to be overcome in reducing the losses caused by light reflection on the surface of microstructural perovskites. In this work, surface microstructure engineering is employed in MAPbBr3 microsheets for reducing light reflection and improving light absorption, resulting in high-performance perovskite photodetectors. MAPbBr3 microsheets, which possess different surface morphologies of flat, upright hemisphere arrays and inverted hemisphere arrays (IHAs), are fabricated by a simple microstructure template-assisted space confinement process. The light absorption capacity of IHA MAPbBr3 is significantly higher than that of the other two structures. Hence, IHA photodetectors with excellent figures of merit, including low dark current, decent responsivity, and fast speed, are achieved. Furthermore, the noise of the IHA photodetectors is only ∼10-13 A/, which results in the superior sensitivity for weak light detection with a specific detectivity up to 1011 Jones. Our results demonstrate that surface engineering is a simple, low-cost, yet effective approach to improve the performance of nano-/micro-optoelectronic devices.

Deep-Ultraviolet Transparent Electrode Design for High-Performance and Self-Powered Perovskite Photodetector.

In this study, a highly crystalline and transparent indium-tin-oxide (ITO) thin film was prepared on a quartz substrate via RF sputtering to fabricate an efficient bottom-to-top illuminated electrode for an ultraviolet C (UVC) photodetector. Accordingly, the 26.6 nm thick ITO thin film, which was deposited using the sputtering method followed by post-annealing treatment, exhibited good transparency to deep-UV spectra (67% at a wavelength of 254 nm), along with high electrical conductivity (11.3 S/cm). Under 254 nm UVC illumination, the lead-halide-perovskite-based photodetector developed on the prepared ITO electrode in a vertical structure exhibited an excellent on/off ratio of 1.05 × 104, a superb responsivity of 250.98 mA/W, and a high specific detectivity of 4.71 × 1012 Jones without external energy consumption. This study indicates that post-annealed ITO ultrathin films can be used as electrodes that satisfy both the electrical conductivity and deep-UV transparency requirements for high-performance bottom-illuminated optoelectronic devices, particularly for use in UVC photodetectors.

Exploring the impact of electron transport layer thickness and morphology on perovskite infiltration and photoresponse in HTM-free self-powered photodetector

Methylammonium lead Iodide (MAPbI3) is emerging as the frontrunner for high-performance photo-detection due to its superior optoelectronic characteristics and ease of processing. Titanium dioxide (TiO2) is the commonly employed electron transport layer in conventional perovskite-based photodetectors. However, the fundamental understanding of the role of TiO2 morphology and its thickness on the photodetector performance is yet to be explored explicitly. This work systematically investigates the impact of morphology (mesoporous versus compact TiO2 layer) and thickness of the TiO2 layer (50 nm – 3000 nm) on the MAPbI3 photodetector performance. The devices have been fabricated in a hole transport material (HTM)-free architecture with carbon as the top contact. The heterojunction between MAPbI3 and TiO2 renders the device with self-powered capability. The influence of the perovskite sensitisation in the TiO2 electrodes, carrier recombination characteristics and charge-carrier transfer resistances have been studied using photoluminescence and impedance spectroscopy. The TiO2 layer morphology and thickness affected the MAPbI3 infiltration and film formation kinetics. Impedance and photoluminescence spectroscopies reveal that TiO2 layers, with thickness above 460 nm, negatively affected the device performance. An optimum thickness of 460 nm-mesoporous TiO2 layer exhibited a superior responsivity and rise time of 2.9 A/W and 21 ms, respectively. The poor performance at higher thicknesses is due to the increased interfacial charge transfer resistance and charge carrier recombination. This work is the first report of extensive optimisation and study on the impact of TiO2 film morphology and thickness on the MAPbI3 photodetectors. The present work will be a key for modelling and designing high-performance perovskite photodetectors.

Flexible array of high performance and stable formamidinium-based low-n 2D halide perovskite photodetectors for optical imaging

Metal halide perovskites are attracting increasing attention as photodetectors (PDs) materials due to their excellent photoelectric properties. However, integrating perovskite to realize high-resolution perovskite pixel arrays remains critical to enable practical devices. Herein, we demonstrate a high-responsivity and stable 10 × 10 flexible PDs array based on formamidinium-based quasi-2D Ruddlesden-Popper (BA)2FAPb2I7 (n = 2) (BA= butylammonium, C4H9NH3+) perovskite elements for image sensing. The high-performance (BA)2FAPb2I7 arrays are synthesized on a polyethylene terephthalate (PET) flexible substrate, on a large scale, high quality, and controllable manner by introducing Au nanoparticles to enhance film quality upon the annealing process and recrystallization by applying formamidinium chloride (FACl) post-treatment to reduce perovskite film defects, combined with an innovative SiO2-assisted hydrophilic and hydrophobic surface treatment strategy. The prepared flexible PDs arrays show excellent optoelectronic properties with high responsivity (5.9 A W−1), a detectivity of 8.2 × 1012 Jones, large on/off current ratio (up to 3 × 104), ultimate response speed (12.8 μs/10.1 μs), and wide spectral response range. In addition, the device shows outstanding mechanical stability under severe bending (θ = 120°) and excellent folding durability after thousands of bending cycles. It also exhibits excellent environmental stability with only a slight degradation of photoresponse after 100 days of storage under the ambient environment. Finally, the integrated flexible PDs arrays can be used as an effective visible light image sensor with good spatial resolution, paving a multifunctional and competitive way for future wearable sensors and artificial vision systems. One-sentence summaryLow-dimensional halide perovskite layers pixelized on a polyethylene terephthalate (PET) flexible substrate provide high performance photodetectors.

Facile Vertical Structure Broadband Photodetectors Enabled by Polyvinylpyrrolidone-Regulated Perovskite and Near-Infrared-Sensitive Lead Phthalocyanine.

Broadband photodetectors have drawn tremendous attention in many application areas such as imaging, optical communication, and biochemical sensing. Perovskite is a star material with broad spectral absorption, but it is challenging to develop ultraviolet-visible-near-infrared (UV-Vis-NIR) ultra-broadband photodetectors due to the insufficient absorption in the near-infrared region. Moreover, it is difficult to construct a diode-type photodetector with a simple vertical structure based only on perovskite materials. Here, facile vertical structure broadband photodetectors were fabricated based on heterojunctions that were composed of perovskite MAPbI3 films with UV-Vis absorption spectrum and small organic molecule lead phthalocyanine (PbPc) with strong NIR optical absorption, resulting in UV-Vis-NIR ultra-broadband photodetection. The quality of MAPbI3 films was improved by introducing polyvinylpyrrolidone (PVP) modification, and subsequently, the corresponding MAPbI3/PbPc heterojunction-based photodetectors exhibited rectification characteristics and reduced reverse dark currents. When the PVP mass ratio is 1 wt%, the photodetector achieved the best performance that the spectral response uniformity factor was as high as 0.77, the photoresponsivity exceeded 10 A/W, and the photoresponse time was less than 0.5 ms under a light intensity of 0.013 mW/cm2 in the UV-Vis to NIR spectral range. These results are comparable or superior to those of some inorganic, organic, and perovskite photodetectors reported previously. This study would provide an effective strategy to construct high-performance perovskite photodetectors based on a simple vertical structure, paving the way to the realization of UV-Vis-NIR broadband photodetection.

Improved Perovskite CH3NH3PbI3 Thin Films by ZIF‐67 Additive Assisted Co Ion Doping toward High‐Performance and Stable Photodetectors

AbstractLead halide perovskites are considered important materials for the fabrication of high‐performance optoelectronic devices. However, the poor quality of thin films with abundant grain boundaries and defect states greatly lower the performance and stability of as‐fabricated devices. In the present work, the growth of improved perovskite CH3NH3PbI3 thin films through Co‐based zeolite imidazole framework (ZIF‐67) additive assisted Co ion doping is reported. Investigation of the morphological, structural, optical, and electrical properties shows that the Co ion doped CH3NH3PbI3 (CH3NH3Pb0.98Co0.02I3) thin films exhibit low grain boundaries, low defect states, and improved structural stabilities. The positive roles of suppression of defect states are further demonstrated by improved performance and stability of photodetectors based on CH3NH3Pb0.98Co0.02I3 thin films. Finally, density functional theory calculations are performed to reveal the mechanisms of passivation of undercoordinate Pb2+ vacancy defect states by Co ion doping. The results provided in this work will pave the way toward the fabrication of high performance and stable perovskite photodetectors in the future.

Highly Sensitive Tin-Lead Perovskite Photodetectors with Over 450 Days Stability Enabled by Synergistic Engineering for Pulse Oximetry System.

Low-bandgap tin (Sn)-lead (Pb) halide perovskites can achieve near-infrared response for photodetectors. However, the Sn-based devices suffer from notorious instability and high defect densities due to the oxidation propensity of Sn2+ . Herein, a multifunctional additive 4-amino-2,3,5,6-tetrafluorobenzoic acid (ATFBA) is presented, which can passivate surface defects and inhibit the oxidation of Sn2+ through hydrogen bonds and chelation coordination from the terminal amino and carboxyl groups. The perfluorinated benzene ring structure of ATFBA affords the passivator assembled at the grain boundaries to enhance the water resistance. With the synergistical passivation of these functional groups, the Sn-Pb perovskite photodetector exhibits a remarkable responsivity of 0.52AW-1 and an excellent specific detectivity of 5.34×1012 Jones at 850nm, along with remaining 97% of its initial responsivity over 450 days. Benefitting from high sensitivity, the photodetector is integrated into a pulse oximetry sensor visualization system, yielding accurate blood oxygen saturation and heart rate with less than 2% error. This work paves the avenue toward constructing high-performance and stable Sn-Pb perovskite photodetectors for practical applications.

Single-pixel color imaging based on a high-performance MAPbI3 perovskite photodetector

Metal halide perovskites with excellent optoelectronic properties show great promise in optical imaging. However, the complex fabrication process of high-density perovskite image sensors limits its development. Herein, we report a simple perovskite color imaging system by combining a single high-performance perovskite photodetector (PD) and the advanced Fourier single-pixel imaging algorithm. We introduce an atomic layer deposition-TiO2 layer and a Spiro-OMeTAD layer to optimize the band energy level arrangement of the perovskite PD, suppressing the dark current and improving the photocurrent of the device, respectively. The optimized perovskite PD with flat spectral response covering all visible wavelength exhibits a high responsivity of 238 mA/W at zero bias, a high special detectivity of 1.13 × 1013 Jones, and a linear dynamic range of 132 dB. In order to bypass the fabrication of the high-density perovskite PD array, we set up a single-pixel imaging system based on an optimized high-performance perovskite PD, demonstrating a high-quality color imaging result. This work provides a perspective for perovskite image sensors and injects vitality into the single-pixel imaging technology.

Self-powered CH3NH3PbI3 perovskite photodiode with a noise-suppressible passivation layer of poly(methyl methacrylate).

Organohalide perovskite materials and related optoelectronic applications have drawn significant attention due to their promising high-performance photon-to-electricity conversion efficiencies. Herein, we demonstrate a highly sensitive self-powered perovskite-based photodetector created with a noise-current-suppressible passivation layer of poly(methyl methacrylate) (PMMA) at the interface between a CH3NH3PbI3 light-absorbing layer and a NiOx hole-transporting layer. Along with the defect passivation effect, the PMMA layer effectively diminishes unwanted carrier recombination losses at the interface, resulting in a significant reduction of the leakage/noise current. Consequently, without external bias, a remarkably high level of specific detectivity (∼4.5 × 1013 Jones from the dark current and ∼0.81 × 1012 Jones from the noise current) can be achieved due to the use of the PMMA passivation layer, greatly exceeding those of conventional unpassivated perovskite devices. Moreover, we observed a very wide linear dynamic response range of ∼129 dB together with rapid rise and decay response times of ∼52 and ∼18 µs, respectively. Overall, these results provide a solid foundation for advanced interface-engineering to realize high-performance self-powered perovskite photodetectors for various optoelectronic applications.

Self-Powered and Low-Noise Perovskite Photodetector Enabled by a Novel Dopant-Free Hole-Transport Material with Bottom Passivation for Underwater Blue Light Communications.

Designing dopant-free hole-transport materials (HTMs) is a facile and effective strategy to realize high-performance organic-inorganic hybrid perovskite (OIHP) photodetectors. Herein, a novel phenothiazine polymer, poly[4-(10H-phenothiazin-10-yl)-N,N-bis(4-methoxyphenyl)aniline] (PPZ-TPA), was synthesized and employed as a promising HTM in OIHP photodetectors. The triphenylamine donor unit was combined with a phenothiazine core, furnishing the polymer with a suitable highest occupied molecular orbital level, favorable thermal stability, and appropriate film morphology. The sulfur atom in the phenothiazine functional group can intentionally passivate the undercoordinated Pb2+ of OIHP films, suppressing nonradiative recombination and yielding an ultralow dark current density of 1.26 × 10-7 A cm-2 under -0.1 V, as well as a low-noise current of 3.75 × 10-13 A Hz-1/2 at 70 Hz. Encouragingly, the self-powered PPZ-TPA-based OIHP photodetectors were successfully integrated into a blue light communication system for the first time, demonstrating their application for receiving and transmitting light signals with a transmission rate of 300 bps. In addition, the PPZ-TPA-based devices exhibit nearly 1 year shelf stability without obvious degradation. We believe that PPZ-TPA demonstrates great potential to achieve high-performance perovskite photodetectors, also providing a strategy for the design of novel HTMs.

Surface-Plasmonic-Coupled Photodetector Based on MAPbI3 Perovskites with Au Nanoparticles: Significantly Enhanced Photoluminescence and Photodetectivity

Organic–inorganic metal halide perovskites (OMHPs) are promising active materials suitable for highly efficient solar cells, photodetectors, light-emitting diodes, and sensors. In this study, methylammonium lead iodide (MAPbI3) thin sheets (TSs) were synthesized as OMHPs using both hybrid vapor-solution method for optical study and anti-solvent solution method for the photodetector. π-Conjugated polyelectrolyte (π-CPE), such as poly(9,9-bis(4′-sulfonatobutyl)fluorene-alt-1,4-phenylene) potassium (FPS-K), was spin-coated on the MAPbI3 TS, and functionalized gold nanoparticles (Au-NPs) were hybridized. The laser confocal microscope photoluminescence (PL) intensity of the MAPbI3 TS was significantly enhanced after hybridization with Au-NPs/FPS-K, owing to the passivating effect of the FPS-K and the generation of extra-photoexcited charges by local surface plasmon resonance (LSPR) coupling with Au-NPs. These results were supported by the variation in the exciton lifetime measured from the time-resolved PL decay curves. The photocurrent of the MAPbI3 photodetector increased up to 1.1 × 104 times, and the photoresponsivity (R) and photodetectivity (D*) increased by 70 and 13 times, respectively, with the hybridization of Au-NPs/FPS-K. The highest D* of the Au-NPs/FPS-K/MAPbI3 photodetector was measured to be 7.5 × 1010 Jones at 735 nm excitation. The power and wavelength dependencies of R and D* for the MAPbI3 photodetector were also significantly improved by the Au-NPs/FPS-K hybrid. These results support the development of high-performance perovskite photodetectors utilizing LSPR coupling with the π-CPE layer.

High photoresponsivity in CH3NH3PbI3-XClx perovskite vertical field effect photo transistors

The synthesis of organic-inorganic hybrid perovskites has greatly facilitated the development of high-performance optoelectronic devices such as photovoltaics, light-emitting diodes, lasers, and photodetectors. We report a CH3NH3PbI3-xClx vertical-structure field-effect phototransistor (VFEPT) using Au/Ag NWs as transparent source electrode (TSE) and exhibiting wideband absorption in the 380 to 800 nm range. Due to the ultra-short channel (78 nm) of VFEPT, multiple circulating holes in laser-induced electron-hole pairs, thus achieving excellent photoconductivity. We further tested the photoelectric performance of VFEPT, which showed that the device had the responsivity (R) is 82.99A/W, the external quantum efficiency (EQE) is 3.3 × 104% and the specific detectivity (D*) is 1.86 × 1012 Jones at VG = -2V, VSD = −5V. When VG = 2.5 V, VSD = 5 V, R reaches 109.15 A/W, EQE reaches 3.3 × 104% and D* reaches 2.45 × 1012 Jones. Organic-inorganic hybrid perovskites provide a new approach for high-performance vertical-structured ultra-short channel perovskite photodetectors.