Photon Absorption Research Articles

A promising photocathode for green hydrogen generation from sanitation water without external sacrificing agent: silver-silver oxide/poly(1H-pyrrole) dendritic nanocomposite seeded on poly-1H pyrrole film

Abstract A novel photocathode has shown promise for generating green hydrogen from sanitation water at a rate of 50 µmol/h per 10 cm², using waste water as an electrolyte in a three-electrode cell. This photocathode is composed of two layers: a poly(1H-pyrrole) seeding layer topped with a silver-silver oxide/poly(1H-pyrrole) (Ag-Ag2O-P1HP) dendritic nanocomposite. The nanocomposite exhibits broad light absorption up to 660 nm and possesses a bandgap of 1.8 eV. SEM images reveal that the Ag-Ag2O-P1HP nanocomposite consists of well-ordered semi-spherical nanoparticles, with an average size between 80 and 100 nm. These spherical nanoparticles offer a large surface area, which enhances photon absorption and trapping efficiency. Additionally, the crystalline structure is characterized by a small crystal size of 32 nm, further contributing to the material’s efficiency. Hydrogen generation performance was evaluated by measuring the current density (J ph) under white light and monochromatic light, compared to the dark current (J o). The photocathode’s sensitivity was tested using four different monochromatic wavelengths: 540, 440, 340, and 730 nm. The first three wavelengths – 540, 440, and 340 nm – resulted in high J ph values of −0.19, −0.20, and −0.21 mA/cm², respectively, indicating significant hydrogen production. Conversely, the 730 nm wavelength produced a lower J ph value of −0.17 mA/cm², as the energy at this wavelength is insufficient to induce significant bond vibrations, resulting in limited hydrogen production. The high efficiency, combined with the straightforward fabrication of this photocathode, suggests that it could be scaled up as a prototype for industrial hydrogen generation applications.

Factors Affecting the Population of Excited Charge Transfer States in Adenine/Guanine Dinucleotides: A Joint Computational and Transient Absorption Study

There is compelling evidence that the absorption of low-energy UV radiation directly by DNA in solution generates guanine radicals with quantum yields that are strongly dependent on the secondary structure. Key players in this unexpected phenomenon are the photo-induced charge transfer (CT) states, in which an electric charge has been transferred from one nucleobase to another. The present work examines the factors affecting the population of these states during electronic relaxation. It focuses on two dinucleotides with opposite orientation: 5′-dApdG-3′ (AG) and 5′-dGpdA-3′ (GA). Quantum chemistry calculations determine their ground state geometry and the associated Franck–Condon states, map their relaxation pathways leading to excited state minima, and compute their absorption spectra. It has been shown that the most stable conformer is anti-syn for AG and anti-anti for GA. The ground state geometry governs both the excited states populated upon UV photon absorption and the type of excited state minima reached during their relaxation. Their fingerprints are detected in the transient absorption spectra recorded with excitation at 266 nm and a time resolution of 30 fs. Our measurements reveal that in the large majority of dinucleotides, chromophore coupling is already operative in the ground state and that the charge transfer process occurs within ~120 fs. The competition among various relaxation pathways affects the quantum yields of the CT state formation in each dinucleotide, which are estimated to be 0.18 and 0.32 for AG and GA, respectively.

Comparison of the mechanisms of DNA damage following photoexcitation and chemiexcitation

In this review, we compare the mechanisms and consequences of electronic excitation of DNA via photon absorption or photosensitization, as well as by chemically induced generation of excited states. The absorption of UV radiation by DNA is known to produce cyclobutane pyrimidine dimers (CPDs) and thymine pyrimidone photoproducts. Photosensitizers are known to enable such transformations using UV-A and visible light by generating triplet species able to transfer energy to DNA. Conversely, chemiexcitation of DNA is a process related to the formation of high energy peroxides whose decomposition leads to triplet excited species. In practice, both photoexcitation and chemiexcitation produce reactive excited species able to promote some DNA nucleobases to their excited state. We discuss the effect of epigenetic methylation modifications of DNA and the role of endogenous and exogenous photosensitizers on the formation of DNA photoproducts via triplet-triplet energy transfer as well as oxidative DNA damages. The mechanisms of pathogenic pathway involving the generation of CPDs via chemiexcitation (namely dark CPDs, dCPDs) are discussed and compared with photoexcitation considering their spatiotemporal characteristics. Recognition of the multifaceted noxious effects of UV radiation opens new horizons for the development of effective electronically excited quenchers, thereby providing a crucial step toward mitigating DNA photodamage.

Tunable nonlinear optical properties in polyaniline-multiwalled carbon nanotube (PANI-MWCNT) system probed under pulsed Nd:YAG laser

The investigation of the nonlinear optical (NLO) properties of polyaniline (PANI) and polyaniline doped with multi-walled carbon nanotube (PANI-MWCNT) in both solution and film forms was conducted using the open-aperture z-scan approach. A Q-switched resonant Nd: YAG laser with a wavelength of 532nm and two different fluences was utilized in this study. Based on the z-scan experiments, it was observed that the NLO behaviour of PANI and PANI-MWCNT composites exhibited a transition from reverse saturable absorption (RSA) to saturable absorption (SA) when the samples changed from a liquid to a film state. Two photon absorption (TPA) and thermally induced nonlinear scattering are the main mechanisms behind the RSA behaviour of the materials in solution form. The reason for SA behaviour of these materials in film form is attributed as the ground-state free electron bleaching in the conduction band due to the increased laser intensity. Due to increased structural disorder and the defect states or trap levels created by the dopants in the PANI system, the NLO properties of the PANI-MWCNT composite in both solution and film forms have significantly improved compared to those of pure PANI. Urbach tail analysis and carbon cluster determination revealed the presence of defect states in the composites system. The composite between PANI and MWCNT was verified using Fourier transform infrared (FTIR) spectroscopy. The functional elements present in the composites are verified by X-ray photoelectron spectroscopy. The NLO parameters of the samples, viz., the nonlinear absorption coefficient (β), the imaginary part of the nonlinear, and susceptibility χi(3) the figure of merit (FOM) of PANI-MWCNT, exhibited a notable enhancement in their values over PANI. Moreover, the PANI-MWCNT film demonstrated superior SA performance and the PANI-MWCNT solution demonstrated better OL performance compared to that of the PANI film and solution respectively. Also the effects of dopant induced structural modifications and lattice disorder on the NLO behaviour of these materials are correlated with the obtained NLO parameters. The tunable NLO properties accomplished by controlling the structural phase and dopant-induced defects enhance the possibility of these nanostructures for applications in optical limiting, optical switching, optical modulation, optical pulse compression and laser pulse narrowing.

Improving the efficiency of polymer solar cells based on chitosan@PVA@rGO composites via gamma-irradiated treatment of rGO nanoparticles

Polymer solar cells (PSCs) are growing as attractive contenders for renewable energy technologies given their low cost, adaptability, and environmental sustainability, rendering them valuable in combating climate change. Interestingly, this work investigates the augmentation of photon absorption and overall efficiency in low-cost, effective active layers (ALs) via gamma irradiation treatment, thereby raising the number of active absorption sites. For the first time, novel Chitosan@PVA@rGO (CPG) composite sheets were created as AL materials and treated to varied dosages of in-situ gamma irradiation (0, 10, 20, 30, and 40 KGy) to optimize their microstructural and physicochemical characteristics. The processed ALs were subjected to comprehensive tests, which included J–V variable evaluation as well as evaluations of microstructure, porosity, morphology, contact angle, optical characteristics, and electrochemical impedance spectroscopy (EIS). The findings reveal that the composites' surface properties got better gradually as gamma irradiation dosages grew; peak performance was reached at 30 KGy (75.9 % apparent porosity and roughness parameter Ra = 6.22 μm). Extended gamma irradiation resulted in increased DSSC efficiency, which reached 6.85 % after 10 KGy and 7.63 % after 20 KGy. High-energy gamma photons boosted mobility and decreased resistive limits by reducing carrier recombination and facilitating charge carrier movement inside CPG compounds. This increased the longevity and charge transfer efficiency of the solar cell. After 30 KGy alteration, the CPG AL's optimized efficiency of 8.78 % and Jsc of 20.23 mA/cm2 indicate a 44.3 % improvement in efficacy over the pristine material. The insertion of oxygen-enriched free radicals into the CPG structure is responsible for the improvement in photovoltaic efficiency because it creates continuous pathways for fast electron transport. This work provides an innovative perspective on the use of heteroatom-doped ALs in PSCs by highlighting the benefits of co-doping and regulated heteroatom species.

Temporal Pound–Rebka experiment as gravitational Aharonov–Bohm effect

One of the classical tests of general relativity is the precision measurements by Pound and Rebka of red-shift/blue-shift of photons in a gravitational field. In this essay, we lay out a temporal version of the Pound–Rebka experiment. The emission and absorption of photons occurs at different times, rather than at different spatial locations as in the original Pound–Rebka experiment. This temporal Pound–Rebka experiment is equivalent to a gravitational Aharonov–Bohm Effect and is testable via current or near future satellite experiments.

Constant-force photonic projectile for long-distance targeting delivery

Abstract Optically controllable delivery of microparticles excites interesting research and applications in various fields because of the noninvasive and noncontact features. However, long-distance delivery with a static low-power light source remains challenging. Here, the constant-force photonic projectile (CFPP) is employed to achieve long-distance delivery of microparticles with a low-power laser beam. The CFPP takes advantage of photon absorption to create a constant optical force within a large range, surpassing traditional tweezers. The concept of CFPP has been experimentally corroborated by remote control over micrometer-sized absorptive particles (APs) using a simple tilted focused beam. At the laser focus, strong photon absorption results in a large constant optical force that ejects the APs along the optical axis. Furthermore, the additional thermal convection field, which attracts particles from a distance into the working range of the CFPP, is utilized to collect the unbound APs for reuse. Finally, we demonstrate the concept of drug delivery by transporting a small microparticle onto a host particle at a remote location. The proposed CFPP provides a new perspective for drug delivery and heat-enhanced photodynamic therapy.

Optical and Methanol Sensing Properties of Al-doped ZnO Thin Film

The study investigates the optical and electrical properties of undoped and aluminum (Al)-doped zinc oxide (ZnO) films, focusing on their performance as gas sensors and their potential applications. Optical analysis, conducted using UV-visible spectrophotometry, reveals that 1% Al-doped ZnO films exhibit the highest transmittance of 91%, indicating superior optical clarity and suitability for applications like solar cell electrodes. In contrast, 3% Al-doped ZnO films show significantly lower transmittance due to increased light scattering and photon absorption. The bandgap of ZnO films decreases with higher Al doping concentrations, from 3.3 eV for undoped ZnO to 3.15 eV for 3% Al-doped ZnO, suggesting enhanced electrical conductivity due to reduced bandgap. The extinction coefficient data demonstrate that 2% Al-doped ZnO has the highest extinction coefficient, reflecting improved light absorption and scattering properties. Electrical characterization through I-V curves indicates that 1% Al-doped ZnO films have higher current (121 µA) compared to undoped (431 µA) and higher doping concentrations, attributed to enhanced carrier concentration and mobility. Sensitivity tests show that 2.5% Al-doped ZnO films exhibit the highest sensitivity to methanol vapor, with a significant reduction in resistance compared to 0.5% Al-doped ZnO films. Resistance measurements with varying methanol volumes reveal a rapid decrease upon gas introduction, stabilizing and then increasing as the gas is removed. Sensitivity analysis indicates that 100 µL methanol provides the highest sensitivity (97%) at 60°C, while 2% Al-doped ZnO films show consistent sensitivity at 60 °C and 100 °C, but not at 80 °C.

Ultrathin photonic absorber with wideband polarization independency characteristics using fractal combinations of ring resonators on ZnSe substrate

Ultrathin photonic absorber with wideband polarization independency characteristics using fractal combinations of ring resonators on ZnSe substrate

Photons, Excitons, and Electrons in Covalent Organic Frameworks.

Covalent organic frameworks (COFs) are created by the condensation of molecular building blocks and nodes to form two-dimensional (2D) or three-dimensional (3D) crystalline frameworks. The diversity of molecular building blocks with different properties and functionalities and the large number of possible framework topologies open a vast space of possible well-defined porous architectures. Besides more classical applications of porous materials such as molecular absorption, separation, and catalytic conversions, interest in the optoelectronic properties of COFs has recently increased considerably. The electronic properties of both the molecular building blocks and their linkage chemistry can be controlled to tune photon absorption and emission, to create excitons and charge carriers, and to use these charge carriers in different applications such as photocatalysis, luminescence, chemical sensing, and photovoltaics. In this Perspective, we will discuss the relationship between the structural features of COFs and their optoelectronic properties, starting with the building blocks and their chemical connectivity, layer stacking in 2D COFs, control over defects and morphology including thin film synthesis, exploring the theoretical modeling of structural, electronic, and dynamic features of COFs, and discussing recent intriguing applications with a focus on photocatalysis and photoelectrochemistry. We conclude with some remarks about present challenges and future prospects of this powerful architectural paradigm.

Shrink effects on nanoscale MOS capacitor in visible and NIR spectral Ranges

This research explores the influence of visible and near-infrared light on the electrical characteristics of nanoscale MOS capacitors, examining the effects of light intensity and spectral composition. Photon absorption within the device stimulates an enhancement of the inversion electron layer. A spectral analysis encompassing the ultraviolet to near-infrared range (400–1100 nm) is presented. Research on nanoscale devices of this nature can contribute to a profound understanding of fundamental light-matter interactions at the atomic and molecular scale. This knowledge can pave the way for the development of novel optoelectronic coupled devices, which combine light trigger and electronic functionalities. These devices, when integrated in Photonics Integrated Circuits (PICs), could have applications in areas such as solar cells, photodetectors, and future ultrasmall electronic components.

Two-dimensional P1 approximation (P1-2D) for the Description of the Radiant Field on Cylindrical Solar Photocatalytic Reactors

The local volumetric rate of photon absorption (LVRPA) was formulated by solving the radiative transfer equation (RTE) in polar coordinates with the P1 approximation approach (P1-2D) for the description of the radiant field in cylindrical solar photocatalytic reactors. A general expression of the LVRPA was formulated that can be employed on cylindrical photocatalytic reactors with an incident radiation constant along the reactor length. CPC and tubular photocatalytic reactors were used as reactor models and Lambert's cosine law (irradiance) was considered when using the boundary conditions. Simulations were carried out using the commercial TiO2-P25, its optical properties taken from the literature. The LVRPA was found to decrease exponentially from the reactor wall to its center. literature rate of photon absorption per unit of reactor length (VRPA/H) increased exponentially with the catalyst loading until a value where no significant increase was observed and was found to increase with reactor radius, information that agrees with the literature. The optimum catalyst loading with the CPC reactor was about 0.364 g/L with a reactor radius equal to 1.65 cm similar to that found in the literature when using the six-flux model in two dimensions (SFM-2D). The apparent optical thickness τ_App1 newly formulated with the P1 approximation was introduced for optimization purposes and was found more reliable than the optical thickness τ. This parameter not only removes the dependence of the optimum catalyst loading on the reactor's radius but also its dependence on catalyst albedo. τ_App1 was found about 9.73 and 14.6 for CPC and tubular reactors respectively and provides the optimum catalyst loading and the reactor radius that optimize the radiation absorption inside both reactors.

Thermo-optical analysis of a nanocone based solar absorber for thermophotovoltaic applications

Abstract We investigate the optical and thermal response of a 2D photonic crystal absorber composed of tungsten nanocones, with complete and truncated shapes used in a solar thermophotovoltaic (STPV) system. We explain how the absorption and temperature of the structure are affected by the presence of a protection layer, lens and an emitter. The total efficiency and contribution of thermal emittance of complete nanocone arrays are compared with truncated absorbers. Based on our results, the efficiency of a non-protected nanocone hits 67% at 400 sunlight and the temperature reaches 1350 K. By adding a silica layer on the absorber, the efficiency slightly reduces to 61%. In addition, we observed a reduction in the efficiency of all studied absorbers at higher sunlight concentration factors. Our results also indicate that the thickness of a silica layer on the tungsten substrate does not have a noticeable change in the efficiency. Finally, the deformation of the structure due to surface diffusion is studied. This study paves the way toward a multi-physical analysis of photonic crystal absorbers in STPV systems.

Polypyrrole-bismuth tungstate/polypyrrole core-shell for optoelectronic devices exhibiting Schottky photodiode behavior

A polypyrrole-bismuth tungstate (Ppy-Bi2WO6) core-shell nanocomposite (n-type material) has been developed on a layered Ppy (p-type) base as an efficient light-capturing material exhibiting photodiode behavior. This device demonstrates promising sensitivity for light sensing and captures across a broad spectral range, from near IR to UV. The Bi2WO6/Ppy nanocomposite boasts an optimal bandgap of 2.0 eV, compared to 3.4 eV for Ppy and 2.5 eV for Bi2WO6. The crystalline size of the core-shell composite is approximately 21 nm, emphasizing its photon absorption capabilities. The composite particles, around 100 nm in length, feature a highly porous morphology that effectively traps incident photons. The performance of this optoelectronic device is evaluated using current density (J) measurements under light (Jph) and dark (Jo) conditions. In darkness, the n-p type semiconductor exhibits limited current with a Jo of −0.22 mA cm−2 at 2.0 V. When exposed to white light, the Ppy- Bi2WO6/Ppy device generates hot electrons, achieving a Jph value of 1.1 mA/cm−2 at 2.0 V. It shows a superior responsivity (R) of 6.6 mA/W at 340 nm, gradually decreasing to 6.3 mA/W at 440 nm and 4.2 mA/W at 540 nm, indicating high sensitivity across the UV-Vis spectrum. At 730 nm, the R-value is 2.6 mA/W, highlighting its sensitivity in the near IR region. Additionally, at 340 nm, the device achieves a detectivity (D) value of 0.15 × 10¹⁰ Jones, which decreases with longer wavelengths to 0.14 × 10¹⁰ Jones at 440 nm, 0.9 × 10⁹ Jones at 540 nm, and 0.63 × 10⁹ Jones at 730 nm. With its great stability, low cost, easy fabrication, and potential for mass production, this optoelectronic light sensor and photodiode device holds significant promise for industrial applications as a highly effective optoelectronic device.

Mechanical properties and radiological implications of replacing sand with waste ceramic aggregate in ordinary concrete

The mining of aggregates for the production of concrete creates ecological problems. In this study, the effect of partially replacing sand as fine aggregate (FA) with waste ceramic tiles (WCT) on the density, compressive strength (CS), specific radioactivity of naturally occurring radioactive materials (238U, 232Th, and 40K), and the radiation shielding competence of concrete was investigated. Ordinary concrete samples consisting of cement, fine aggregate (river sand), coarse aggregate (granite), and water were prepared in 50 mm × 50 mm x 50 mm cubical steel moulds. The samples were coded as C-WCT0, C-WCT5, C-WCT10, C-WCT15, C-WCT20, and C-WCT25, representing concrete samples in which the FA component was replaced by 0, 5, 10, 15, 20, and 25% pulverized WCT, respectively. The CS and density of the samples were determined after 7-, 14-, and 28-day curing periods. The gamma spectrometric method was used to determine the specific activity of 238U, 232Th, and 40K using a hyper pure germanium detector. The photon and neutron shielding parameters of the concrete blocks were calculated with the aid of the EPICS2017 cross-section library and relevant standard formulae. The mean CS for each concrete category increase with curing age. The density of the concrete varied from 2213 kg/m3 to 2488 kg/m3 as the FA replacement level rose to 15%. Using WCT as a partial replacement for FA altered the chemical composition and decreased the specific activities of 238U, 232Th, and 40K, in the concrete samples. C-WCT15 had the best gamma photon and fast neutron absorption features among the concrete samples. The use of WCT as aggregate in concrete production is a sustainable and environmental-friendly way of producing concrete for general civil engineering and shielding applications in medical and other radiation facilities. This study also affirms that using alternative materials with lower specific activity to replace sand is radiologically desirable in reducing the indoor radiation dose of occupants of concrete-based structures. The replacement of 15% sand by WCT produced stronger, radiologically safer, and more effective radiation absorbing concrete.

Investigating the impact of ITO substrates on the optical and electronic properties ofWSe2monolayers.

Two-dimensional (2D) materials, particularly transition metal dichalcogenides (TMDCs), have gathered significant attention due to their interesting electrical and optical properties. Among TMDCs, monolayers of WSe2exhibit a direct band gap and high exciton binding energy, which enhances photon emission and absorption even at room temperature. This study investigates the electronic and optical properties of WSe2monolayers when they are mechanically transferred to indium tin oxide (ITO) substrates. ITO is a transparent conducting electrode (TCE) used in many industrial opto-electronic applications. Samples were mechanically transferred under ambient conditions, consequently trapping an adsorbate layer of atmospheric molecules unintentionally between the monolayer and the substrate. To reduce the amount of adsorbates, some samples were thermally annealed. Atomic force microscopy (AFM) confirmed the presence of the adsorbate layer under the TMD and its partial removal after annealing. X-ray photoelectron spectroscopy (XPS) confirmed the presence of carbon species among the adsorbates even after annealing. Photoluminescence (PL) measurements show that WSe2remains optically active on ITO even after annealing. Moreover, the luminescence intensity and energy are affected by the amount of adsorbates under the WSe2monolayer. Scanning Tunnelling Spectroscopy reveals that the TMD monolayer is n-doped, and that its band edges form a type I band alignment with ITO.. Surface potential measurements show a polarity change after annealing, indicating that polar molecules, most likely water, are being removed. This comprehensive study shows that a TCE does not quench WSe2luminescence even after a prolonged thermal annealing, although its optical and electronic properties are affected by unintentional adsorbates. These findings provide insights for better understanding, controlling, and design of 2D material heterostructures on TCEs.

Spatially selective actuation of liquid-crystalline polymer films through two-photon absorption processes

Soft materials that respond to external stimuli are promising candidates for next-generation actuators with human-friendly nature1,2. Among various stimuli to induce strain, light offers spatial selectivity, which allows versatile motion of a continuous body. However, spatial selectivity of photoactuation has been limited in two dimension due to the predominant absorption of photons by chromophores near a light source in accordance with Beer-Lambert law. Here, we report the deformation of crosslinked liquid-crystalline polymer films triggered by two-photon absorption. The films containing azotolane moieties show photoinduced deformation upon irradiation with fs laser pulses through two-photon absorption. The direction of photoinduced bending is controlled by depth-selective excitation with a focused laser beam. Furthermore, the mode of deformation is transformed from bending to twisting by irradiating spots near an edge of the film. Inhomogeneous photoirradiation with high spatial selectivity allows an infinite variation of three-dimensional motions even apart from preprogrammed behavior, which would be advantageous especially in application to microactuators.

Functional Nano-Metallic Coatings for Solar Cells: Their Theoretical Background and Modeling

We have collected theoretical arguments supporting the functional role of nano-metallic coatings of solar cells, which enhance solar cell efficiency via by plasmon-strengthening the absorption of sun-light photons and reducing the binding energy of photoexcitons. The quantum character of the plasmonic effect related to the absorption of photons (called the optical plasmonic effect) is described in terms of the Fermi golden rule for the quantum transitions of semiconductor-band electrons induced by plasmons from a nano-metallic coating. The plasmonic effect related to the lowering of the exciton binding energy (called the electrical plasmonic effect) is of particular significance for metalized perovskite solar cells and is also characterized in quantum mechanics terms. The coupling between plasmons in nanoparticles from a coating with band electrons in a semiconductor substrate significantly modifies material properties (dielectric functions) both of the particles and the semiconductor, beyond the ability of the classical electrodynamics to describe.

Charge Diffusion and Repulsion in Semiconductor Detectors.

Semiconductor detectors for high-energy sensing (X/γ-rays) play a critical role in fields such as astronomy, particle physics, spectroscopy, medical imaging, and homeland security. The increasing need for precise detector characterization highlights the importance of developing advanced digital twins, which help optimize the design and performance of imaging systems. Current simulation frameworks primarily focus on modeling electron-hole pair dynamics within the semiconductor bulk after the photon absorption, leading to the current signals at the nearby electrodes. However, most simulations neglect charge diffusion and Coulomb repulsion, which spatially expand the charge cloud during propagation due to the high complexity they add to the physical models. Although these effects are relatively weak, their inclusion is essential for achieving a high-fidelity replication of real detector behavior. There are some existing methods that successfully incorporate these two phenomena with minimal computational cost, including those developed by Gatti in 1987 and by Benoit and Hamel in 2009. The present work evaluates these two approaches and proposes a novel Monte Carlo technique that offers higher accuracy in exchange for increased computational time. Our new method enables more realistic performance predictions while remaining within practical computational limits.

Intraband transitions at a CsPbBr3/GaAs heterointerface in a two-step photon upconversion solar cell

Two-step photon upconversion solar cells (TPU-SCs) based on III–V semiconductors can achieve enhanced sub-bandgap photon absorption because of intraband transitions at the heterointerface. From a technological aspect, the question arose whether similar intraband transitions can be realized by using perovskite/III–V semiconductor heterointerfaces. In this article, we demonstrate a TPU-SC based on a CsPbBr3/GaAs heterointerface. Such a solar cell can ideally achieve an energy conversion efficiency of 48.5% under 1-sun illumination. This is 2.1% higher than the theoretical efficiency of an Al0.3Ga0.7As/GaAs-based TPU-SC. Experimental results of the CsPbBr3/GaAs-based TPU-SC show that both the short-circuit current JSC and the open-circuit voltage VOC increase with additional illumination of sub-bandgap photons. We analyze the excitation power dependence of JSC for different excitation conditions to discuss the mechanisms behind the enhancement. In addition, the observed voltage-boost clarifies that the JSC enhancement is caused by an adiabatic optical process at the CsPbBr3/GaAs heterointerface, where sub-bandgap photons efficiently pump the electrons accumulated at the heterointerface to the conduction band of CsPbBr3. Besides the exceptional optoelectronic properties of CsPbBr3 and GaAs, the availability of a CsPbBr3/GaAs heterointerface for two-step photon upconversion paves the way for the development of high-efficiency perovskite/III–V semiconductor-based single-junction solar cells.