{"title":"Kinetic inductance parametric converter","authors":"M. Khalifa, P. Feldmann, J. Salfi","doi":"10.1103/physrevapplied.22.024025","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024025","url":null,"abstract":"Parametric converters are parametric amplifiers that mix two spatially separate nondegenerate modes and are commonly used for amplifying and squeezing microwave signals in quantum computing and sensing. In Josephson parametric converters, the strong localized nonlinearity of the Josephson junction limits the amplification and squeezing, as well as the dynamic range, in current devices. In contrast, a weak distributed nonlinearity can provide higher gain and dynamic range, when implemented as a kinetic inductance (KI) nanowire of a dirty superconductor, and has additional benefits such as resilience to magnetic field, higher-temperature operation, and simplified fabrication. Here, we propose, demonstrate, and analyze the performance of a KI parametric converter that relies on the weak distributed nonlinearity of a Nb-Ti-N KI nanowire. The device utilizes three-wave mixing induced by a dc current bias. We demonstrate its operation as a nondegenerate parametric amplifier with high phase-sensitive gain, reaching two-mode amplification and deamplification of approximately 30 dB for two resonances separated by 0.8 GHz, in excellent agreement with our theory of the device. We observe a dynamic range of <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo>−</mo><mn>108</mn></math> dBm at 30 dB gain. Our device can significantly broaden applications of quantum-limited signal processing devices including phase-preserving amplification and two-mode squeezing.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"22 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matteo Castellani, Owen Medeiros, Reed A. Foster, Alessandro Buzzi, Marco Colangelo, Joshua C. Bienfang, Alessandro Restelli, Karl K. Berggren
{"title":"Nanocryotron ripple counter integrated with a superconducting nanowire single-photon detector for megapixel arrays","authors":"Matteo Castellani, Owen Medeiros, Reed A. Foster, Alessandro Buzzi, Marco Colangelo, Joshua C. Bienfang, Alessandro Restelli, Karl K. Berggren","doi":"10.1103/physrevapplied.22.024020","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024020","url":null,"abstract":"Decreasing the number of cables that bring heat into the cryostat is a critical issue for all cryoelectronic devices. In particular, arrays of superconducting nanowire single-photon detectors (SNSPDs) could require more than <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mn>10</mn><mn>6</mn></msup></math> readout lines. Performing signal-processing operations at low temperatures could be a solution. Nanocryotrons, superconducting nanowire three-terminal devices, are good candidates for integrating sensing and electronics on the same technological platform as SNSPDs in photon-counting applications. In this work, we demonstrate that it is possible to read out, process, encode, and store the output of SNSPDs using exclusively superconducting nanowires patterned on niobium nitride thin films. In particular, we present the design and development of a nanocryotron ripple counter that detects input voltage spikes and converts the number of pulses to an <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>N</mi></math>-digit value. The counting base can be tuned from 2 to higher values, enabling higher maximum counts without enlarging the circuit. As a proof of principle, we first experimentally demonstrate the building block of the counter, an integer-<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>N</mi></math> frequency divider with <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>N</mi></math> ranging from 2 to 5. Then, we demonstrate photon-counting operations at 405 nm and 1550 nm by coupling an SNSPD with a two-digit nanocryotron counter partially integrated on chip. The two-digit counter can operate in either base 2 or base 3, with a bit-error rate lower than <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mn>2</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math> and a count rate of <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mn>10</mn><mn>7</mn></msup><mspace width=\"0.2em\"></mspace><msup><mrow><mrow><mi mathvariant=\"normal\">s</mi></mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. We simulate circuit architectures for integrated readout of the counter state and we evaluate the capabilities of reading out an SNSPD megapixel array that would collect up to <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mn>10</mn><mn>12</mn></msup></math> counts per second. The results of this work, combined with our recent publications on a nanocryotron shift register and logic gates, pave the way for the development of nanocryotron processors, from which multiple superconducting platforms may benefit.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"28 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Laloy-Borgna, L. Vovard, A. Rohfritsch, L. Wang, J. Ngo, M. Perier, A. Drainville, F. Prat, M. Lafond, C. Lafon, S. Catheline
{"title":"Magnetic microelastography for evaluation of ultrasound-induced softening of pancreatic cancer spheroids","authors":"G. Laloy-Borgna, L. Vovard, A. Rohfritsch, L. Wang, J. Ngo, M. Perier, A. Drainville, F. Prat, M. Lafond, C. Lafon, S. Catheline","doi":"10.1103/physrevapplied.22.024024","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024024","url":null,"abstract":"Pancreatic ductal adenocarcinoma is a devastating disease with very low survival rates 5 years after diagnosis. The main reason for this dismal prognosis is the thick stroma which both protects tumor cells from drug penetration and supports tumor development. Ultrasound inertial cavitation is a promising treatment with potential for stromal disruption, enhancing tumor cells’ sensitivity to chemical agents and biomodulators. Our goal was to develop a dedicated microelastography setup allowing us to measure the elasticity of <i>in vitro</i> tumor models called spheroids. In a second step, the impact of cavitation treatment on their mechanical properties was assessed. A transcranial magnetic stimulation clinical device was used to induce shear waves in the spheroids containing magnetic nanoparticles. Using an inverted optical microscope, particle imaging velocimetry, and noise correlation algorithms, the shear wave velocity, indicative of the medium’s elasticity, could be measured. Shear waves generated by the magnetic pulse inside the spheroids were detected and their velocity was measured using noise correlation elastography. This allowed the estimation of the spheroids’ elasticity. Cavitation treatment softened them significantly, and the impact of the exposure conditions and the spheroids’ composition have been studied. In the future, such a method could be used to monitor cavitation treatments. In addition, since it is now well established that mechanical constraints and elasticity play an important role in tumor growth, it is of great interest to measure the elasticity of tumor models to better understand the mechanisms of tumor growth.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"74 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elizabeth Robertson, Luisa Esguerra, Leon Meßner, Guillermo Gallego, Janik Wolters
{"title":"Machine-learning optimal control pulses in an optical quantum memory experiment","authors":"Elizabeth Robertson, Luisa Esguerra, Leon Meßner, Guillermo Gallego, Janik Wolters","doi":"10.1103/physrevapplied.22.024026","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024026","url":null,"abstract":"Efficient optical quantum memories are a milestone required for several quantum technologies, including repeater-based quantum key distribution and on-demand multiphoton generation. We present an efficiency optimization of an optical electromagnetically induced transparency (EIT) memory experiment in a warm cesium vapor using a genetic algorithm and analyze the resulting wave forms. The control pulse is represented either as a Gaussian or free-form pulse and the results from the optimization are compared. We see an improvement factor of 3(7)% when using optimized free-form pulses. By limiting the allowed pulse energy in a solution, we show an energy-based optimization giving a 30% reduction in energy, with minimal efficiency loss.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"75 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wenhai Liang, Shuman Du, Renjing Chen, Chengru Wu, Xiong Shen, Peng Wang, Jun Liu, Ruxin Li
{"title":"Power-in-bucket enhancement in tiled-aperture coherent beam combining through inducing spatial chirp","authors":"Wenhai Liang, Shuman Du, Renjing Chen, Chengru Wu, Xiong Shen, Peng Wang, Jun Liu, Ruxin Li","doi":"10.1103/physrevapplied.22.024018","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024018","url":null,"abstract":"Spatial gaps between sub-beams in high-peak-power lasers with tiled-aperture-based coherent beam combining (TACBC) give rise to relatively strong sidelobes and impair the power in bucket (PIB) at far field<b>.</b> To address the aforementioned issue, spatial chirp is employed in this paper to fill the gaps and further enhance PIB. With two sub-beams, both simulations and experiments indicate that spatial chirp can boost PIB by 1.8 times at a gap-beam width ratio of 0.2. The same enhancement is observed in simulations even when four sub-beams are considered. To put it briefly, the spatial-chirp-assisted TACBC approach holds the potential in boosting focal intensity during constructing tens to hundreds of petawatt (PW) lasers.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"6 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anthony D’Addario, Johnathan Kuan, Noah F. Opondo, Ozan Erturk, Tao Zhou, Sunil A. Bhave, Martin V. Holt, Gregory D. Fuchs
{"title":"Stroboscopic x-ray diffraction microscopy of dynamic strain in diamond thin-film bulk acoustic resonators for quantum control of nitrogen-vacancy centers","authors":"Anthony D’Addario, Johnathan Kuan, Noah F. Opondo, Ozan Erturk, Tao Zhou, Sunil A. Bhave, Martin V. Holt, Gregory D. Fuchs","doi":"10.1103/physrevapplied.22.024016","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024016","url":null,"abstract":"Bulk-mode acoustic waves in a crystalline material exert lattice strain through the thickness of the sample, which couples to the spin Hamiltonian of defect-based qubits such as the nitrogen-vacancy (N-<i>V</i>) center defect in diamond. This mechanism has previously been harnessed for unconventional quantum spin control, spin decoherence protection, and quantum sensing. Bulk-mode acoustic wave devices are also important in the microelectronics industry as microwave filters. A key challenge in both applications is a lack of appropriate operando microscopy tools for quantifying and visualizing gigahertz-frequency dynamic strain. In this work, we directly image acoustic strain within N-<i>V</i> center-coupled diamond thin-film bulk acoustic wave resonators using stroboscopic scanning hard x-ray diffraction microscopy at the Advanced Photon Source. The far-field scattering patterns of the nanofocused x-ray diffraction encode strain information entirely through the illuminated thickness of the resonator. These patterns have a real-space spatial variation that is consistent with the bulk strain’s expected modal distribution and a momentum-space angular variation from which the strain amplitude can be quantitatively deduced. We also perform optical measurements of strain-driven Rabi precession of of the N-<i>V</i> center spin ensemble, providing an additional quantitative measurement of the strain amplitude. As a result, we directly measure one of the six N-<i>V</i> spin-stress coupling parameters, <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>b</mi><mo>=</mo><mn>2.73</mn><mo stretchy=\"false\">(</mo><mn>2</mn><mo stretchy=\"false\">)</mo></math> MHz/GPa, by correlating these measurements at the same spatial position and applied microwave power. Our results demonstrate a unique technique for directly imaging ac lattice strain in micromechanical structures and provide a direct measurement of a fundamental constant for the N-<i>V</i> center defect spin Hamiltonian.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"36 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C.K. Safeer, Paul S. Keatley, Witold Skowroński, Jakub Mojsiejuk, Kay Yakushiji, Akio Fukushima, Shinji Yuasa, Daniel Bedau, Fèlix Casanova, Luis E. Hueso, Robert J. Hicken, Daniele Pinna, Gerrit van der Laan, Thorsten Hesjedal
{"title":"Magnetization dynamics driven by displacement currents across a magnetic tunnel junction","authors":"C.K. Safeer, Paul S. Keatley, Witold Skowroński, Jakub Mojsiejuk, Kay Yakushiji, Akio Fukushima, Shinji Yuasa, Daniel Bedau, Fèlix Casanova, Luis E. Hueso, Robert J. Hicken, Daniele Pinna, Gerrit van der Laan, Thorsten Hesjedal","doi":"10.1103/physrevapplied.22.024019","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024019","url":null,"abstract":"Understanding the high-frequency transport characteristics of magnetic tunnel junctions (MTJs) is crucial for the development of fast-operating spintronics memories and radio frequency devices. Here, we present the study of a frequency-dependent capacitive current effect in <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Co</mi><mi>Fe</mi><mi mathvariant=\"normal\">B</mi></mrow><mo>/</mo><mrow><mi>Mg</mi><mi mathvariant=\"normal\">O</mi></mrow></math>-based MTJs and its influence on magnetization dynamics using a time-resolved magneto-optical Kerr effect technique. In our device, operating at gigahertz frequencies, we find a large displacement current of the order of mA, which does not break the tunnel barrier of the MTJ. Importantly, this current generates an Oersted field and spin-orbit torque, inducing magnetization dynamics. Our discovery holds promise for building robust MTJ devices operating under high current conditions, also highlighting the significance of capacitive impedance in high-frequency magnetotransport techniques.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"2 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bright spatially coherent beam from carbon-nanotube fiber field-emission cathode","authors":"Taha Y. Posos, Jack Cook, Sergey V. Baryshev","doi":"10.1103/physrevapplied.22.024017","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024017","url":null,"abstract":"Large-area carbon-nanotube (CNT) cathodes made from yarns, films, or fibers have long been promising as next-generation electron sources for high-power rf and microwave-vacuum-electronic devices. However, experimental evidence has highlighted that spatial incoherence of the electron beam produced by such cathodes impeded the progress toward high brightness CNT electron sources and their practical applications. Indeed, typically large-area CNT fibers, films, or textiles emit stochastically across their physical surface at large emission angles and with large transverse spread, meaning large emittance and hence low brightness. In this work, using high-resolution field-emission microscopy, we demonstrate that conventional electroplating of hair-thick CNT fibers followed by a femtosecond laser cutting, producing an emitter surface, solves the described incoherent emission issues extremely well. Strikingly, it was observed that the entire (within the error margin) cathode surface of a radius of approximately <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mn>75</mn><mspace width=\"0.2em\"></mspace><mtext fontfamily=\"times\">μ</mtext><mtext>m</mtext></math> emitted uniformly (with no hot spots) in the direction of the applied electric field. The normalized cathode emittance, i.e., on the fiber surface, was estimated as 26-<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mtext>nm</mtext><mspace width=\"0.2em\"></mspace><mtext>rad</mtext></math> with brightness of <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo>></mo><msup><mn>10</mn><mn>16</mn></msup><mspace width=\"0.2em\"></mspace><mtext>A</mtext><mo>/</mo><mrow><msup><mtext>m</mtext><mn>2</mn></msup><mspace width=\"0.2em\"></mspace><msup><mtext>rad</mtext><mn>2</mn></msup></mrow></math> (or <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo>></mo><msup><mn>10</mn><mn>7</mn></msup><mspace width=\"0.2em\"></mspace><mrow><mi mathvariant=\"normal\">A</mi></mrow><mspace width=\"0.2em\"></mspace><msup><mrow><mi mathvariant=\"normal\">m</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><mspace width=\"0.2em\"></mspace><msup><mi>sr</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup><mspace width=\"0.2em\"></mspace><msup><mrow><mi mathvariant=\"normal\">V</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>) estimated for pulsed-mode operation.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"75 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Randy Lafler, Mark L. Eickhoff, Scott C. Newey, Yamil Nieves Gonzalez, Kurt E. Stoltenberg, J. Frank Camacho, Mark A. Harris, Denis W. Oesch, Adrian J. Lewis, R. Nicholas Lanning
{"title":"Two-way quantum time transfer: a method for daytime space-Earth links","authors":"Randy Lafler, Mark L. Eickhoff, Scott C. Newey, Yamil Nieves Gonzalez, Kurt E. Stoltenberg, J. Frank Camacho, Mark A. Harris, Denis W. Oesch, Adrian J. Lewis, R. Nicholas Lanning","doi":"10.1103/physrevapplied.22.024012","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024012","url":null,"abstract":"High-precision remote clock synchronization is crucial for many classical and quantum network applications. Evaluating options for space-Earth links, we find that traditional solutions may not produce the desired synchronization for low Earth orbits and unnecessarily complicate quantum networking architectures. Demonstrating an alternative, we use commercial off-the-shelf quantum photon sources and detection equipment to synchronize two remote clocks across our free-space testbed utilizing a method called two-way quantum time transfer (QTT). We reach picosecond-scale timing precision under very lossy and noisy channel conditions representative of daytime space-Earth links and software-emulated satellite motion. This work demonstrates how QTT is potentially relevant for daytime space-Earth quantum networking and/or providing high-precision timing in GPS-denied environments.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"2 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Edward Butler-Caddle, K.D.G. Imalka Jayawardena, Anjana Wijesekara, Rebecca L. Milot, James Lloyd-Hughes
{"title":"Distinguishing carrier transport and interfacial recombination at perovskite/transport-layer interfaces using ultrafast spectroscopy and numerical simulation","authors":"Edward Butler-Caddle, K.D.G. Imalka Jayawardena, Anjana Wijesekara, Rebecca L. Milot, James Lloyd-Hughes","doi":"10.1103/physrevapplied.22.024013","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.024013","url":null,"abstract":"In perovskite solar cells, photovoltaic action is created by charge transport layers (CTLs) either side of the light-absorbing metal halide perovskite semiconductor. Hence, the rates for desirable charge extraction and unwanted interfacial recombination at the perovskite-CTL interfaces play a critical role for device efficiency. Here, the electrical properties of perovskite-CTL bilayer heterostructures are obtained using ultrafast terahertz and optical studies of the charge carrier dynamics after pulsed photoexcitation, combined with a physical model of charge carrier transport that includes the prominent Coulombic forces that arise after selective charge extraction into a CTL, and cross-interfacial recombination. The charge extraction velocity at the interface and the ambipolar diffusion coefficient within the perovskite are determined from the experimental decay profiles for heterostructures with three of the highest-performing CTLs, namely <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mtext>C</mtext><mn>60</mn></msub></math>, PCBM and Spiro-OMeTAD. Definitive targets for the further improvement of devices are deduced: fullerenes deliver fast electron extraction, but suffer from a large rate constant for cross-interface recombination or hole extraction. Conversely, Spiro-OMeTAD exhibits slow hole extraction but does not increase the perovskite’s surface recombination rate, likely contributing to its success in solar cell devices.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"14 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141949375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}